Ischemic and hemorrhagic stroke are the two primary types of stroke, each with distinct pathogenesis and clinical presentations (Fig. 1). From a pathophysiological perspective, ischemic stroke occurs when cerebral blood flow is compromised due to arterial occlusion or stenosis, resulting in cerebral ischemia (10). By contrast, hemorrhagic stroke develops from cerebrovascular rupture that causes intracranial bleeding (1). These stroke subtypes also exhibit distinct temporal progression patterns: Ischemic stroke typically manifests with progressive symptom onset, while hemorrhagic stroke presents abruptly. Neuroimaging serves as the diagnostic cornerstone for differentiating between these two cerebrovascular events. Ischemic stroke typically involves areas of cerebral infarction, indicating the presence of tissue damage due to inadequate blood flow. By contrast, patients with hemorrhagic stroke exhibit cerebral hemorrhage or hematoma, highlighting the presence of bleeding within the brain. Complications also vary between the two types of stroke. Hemorrhagic stroke can give rise to complications such as increased intracranial pressure, cerebral edema and rebleeding. These complications are relatively rare in patients with ischemic stroke (19,20).

There are several commonalities between ischemic stroke and hemorrhagic stroke (21). First, both types of stroke present with similar symptoms, such as the sudden onset of a headache, impaired consciousness, limb paralysis and speech impairment. These symptoms serve as key indicators of neurological deficits. Second, both stroke types share several strategies for prevention and treatment. In the acute phase, anticoagulation therapy is often employed to prevent further clot formation or bleeding. Additionally, controlling blood pressure and blood glucose levels is crucial for managing the aftermath of both types of stroke. Rehabilitation, including physical and speech therapy, is also a common approach to aid in the recovery of motor skills and language abilities. These shared pathophysiological features underscore the necessity for an integrated, multidisciplinary strategy encompassing prevention, acute intervention and long-term rehabilitation in managing both ischemic and hemorrhagic stroke (19,20).

Both types of stroke trigger an inflammatory response as part of the body's natural defense mechanism. When a stroke occurs, the body responds by sending immune cells to the damaged area to clear out the damaged tissue and begin the healing process (22-24). Inflammation is a natural response to this injury, but it can cause further damage to brain tissue through the release of harmful chemicals and enzymes. These pathophysiological processes may elevate thrombotic risk and induce vasoconstriction, thereby compromising cerebral perfusion. Furthermore, inflammatory cascades promote fibrotic scar formation (25), which impedes post-stroke neuroplasticity and functional recovery. While inflammation modulation constitutes a critical therapeutic target in stroke management, the inflammatory profiles exhibit both shared and distinct characteristics between ischemic and hemorrhagic stroke subtypes.

Both stroke subtypes share a common inflammatory cascade characterized by early activation of resident immune cells (microglia and astrocytes), which secrete proinflammatory mediators, including cytokines and chemokines (26). These signaling molecules recruit circulating leukocytes to the injury site, notably neutrophils, monocytes and various T cell subsets (27). Neutrophils exacerbate tissue damage through the release of reactive oxygen species and proteolytic enzymes (28). Monocytes subsequently differentiate into macrophage populations with distinct functional phenotypes (29).

The inflammatory responses in different stroke subtypes diverge in their primary origins. In ischemic stroke, inflammation predominantly stems from the ischemic core, where hypoperfusion-induced tissue necrosis releases damage-associated molecular patterns that activate the innate immune system (30). By contrast, in hemorrhagic stroke, blood in the brain parenchyma acts as an irritant and directly triggers inflammation (23). Second, the duration of inflammation is not the same. In ischemic stroke, the inflammatory response occurs in two phases: An acute phase, which starts immediately after the onset of ischemia, and a delayed or secondary phase, which occurs hours to days later. In hemorrhagic stroke, the inflammatory response is more acute and immediate, as bleeding into the brain tissue rapidly triggers the release of inflammatory molecules. Third, inflammatory cells have different activation patterns. Ischemic stroke is characterized by infiltrating immune cells, such as neutrophils and monocytes, into ischemic brain tissue (24). Hemorrhagic stroke elicits a distinct inflammatory response characterized by substantial erythrocyte extravasation and hemoglobin release. These blood components drive neuroinflammation through two primary mechanisms: Iron-mediated oxidative stress and direct activation of resident and infiltrating immune cells (31).

Macrophages play a pivotal role in orchestrating inflammatory responses (32), with their functional polarization between classically activated (M1) and alternatively activated (M2) phenotypes being crucial for immune homeostasis (33,34). M1 macrophages, characterized by their proinflammatory properties, mediate inflammatory initiation and perpetuation through the secretion of cytokines, including TNF-α, IL-1β and IL-6. These cells perform essential immunological functions such as microbial phagocytosis, pathogen elimination and cellular debris clearance. Current therapeutic strategies for stroke emphasize modulating excessive M1-mediated neuroinflammation to prevent secondary neurological damage, reflecting the established clinical consensus.

M2 macrophages represent an alternatively activated phenotype that mediates tissue regeneration and inflammatory resolution. These immunoregulatory cells secrete anti-inflammatory cytokines, including IL-10 and TGF-β, while promoting key reparative processes such as extracellular matrix remodeling, neovascularization and efferocytosis. Their polarization is primarily driven by IL-4 and IL-13 secreted from T helper (Th)2 lymphocytes, eosinophils and basophils (35). Emerging evidence has demonstrated that M2 polarization significantly attenuates cerebral infarct volume and enhances neurological recovery in stroke models (36). Therapeutic induction of M2 phenotype can be accomplished through multiple strategies, including pharmacological interventions (statins and minocycline) or adoptive transfer of M2-polarized macrophages (37-41). Given their neuroprotective and reparative properties, targeted modulation of macrophage polarization toward the M2 phenotype offers considerable therapeutic potential for stroke treatment.

The aforementioned description illustrates the characterization of inflammation in both types of stroke. Although inflammation in the acute phase causes cellular damage, it is also crucial for cellular debris removal. Modulating the duration of the M1 and M2 phases is crucial to prevent prolonged damage and to promote nerve repair and regeneration.

IL-27 is a heterodimeric cytokine composed of p28 and EBI3 subunits that belongs to the IL-6/IL-12 superfamily (42). This immunoregulatory cytokine serves as a crucial modulator of both the adaptive and innate immune responses. Produced primarily by activated antigen-presenting cells, particularly macrophages and dendritic cells, IL-27 exerts pleiotropic effects on multiple lymphocyte populations, including natural killer (NK), B and T cells (43,44).

The IL-27 receptor is a heterodimeric complex composed of two distinct subunits: Glycoprotein 130 (gp130) and IL-27 receptor α (IL-27Rα) (45-47). IL-27Rα serves as the ligand-specific binding component, while gp130 functions as a shared signal-transducing subunit utilized by multiple cytokines (46). The IL-27Rα subunit demonstrates high-affinity binding to IL-27, initiating downstream signaling upon ligand engagement. Following IL-27 binding, IL-27Rα recruits gp130 to form a functional receptor complex. This activated receptor triggers multiple intracellular signaling cascades, most notably the PI3K-AKT, MAPK and JAK-STAT pathways, ultimately regulating diverse biological processes, including immune responses and inflammatory reactions (48-50) (Fig. 2).

IL-27 has context-dependent immunomodulatory properties, exhibiting both pro-inflammatory and anti-inflammatory effects based on the specific immune microenvironment (51,52). The present study focused particularly on IL-27's regulatory effects on macrophage polarization. In vitro analyses have demonstrated that IL-27 treatment upregulates M1 macrophage markers, including nitric oxide synthase 2 and IFN-γ (53). Notably, in a murine inflammatory bowel disease model, while colonic epithelial cells and intact crypts showed no response to IL-27, tissue-resident macrophages displayed significant reactivity (53). Mechanistic studies have revealed that IL-27 enhances macrophage antiviral activity via phosphorylated STAT1 activation (54,55). In a separate acute lung injury-sepsis model, adipose-derived mesenchymal stem cell (ADMSC) exosomes attenuated inflammation and its sequelae, an effect that was paradoxically reversed by recombinant IL-27 administration (56). Further in vitro experiments showed that ADMSC-derived exosomes suppressed LPS-induced IL-27 secretion from macrophages (56,57). Notably, a comparative cellular study revealed species-specific responses: IL-27 exerted minimal effects on murine macrophages but significantly modulated human macrophages through STAT1/TLR pathway activation, resulting in decreased IL-10 production and pro-inflammatory activation. This response was rapidly terminated by LPS via p38-mediated inhibition of IL-27 signaling (57).

Beyond its role in promoting M1 polarization, IL-27 is capable of downregulating characteristic M2 markers (IL-10 and arginase-1) while inhibiting the secretion of anti-inflammatory cytokines (IL-13 and IL-4) (57-60). However, these observations primarily stem from single-factor experimental systems. In physiological contexts, macrophage polarization is dynamically regulated through complex interactions among multiple mediators. A previous study by Rückerl et al (61) revealed that IL-4, IL-10 and IL-27 collectively orchestrated macrophage activation via sequential upregulation of WSX-1 and IL-4Rα receptors on alternatively activated macrophages.

Notably, IL-27 exhibits distinct immunomodulatory properties in inflammatory microenvironments following tissue injury. In a murine peritonitis model, IL-27 administration significantly reduced peritoneal fluid concentrations of the chemokines MCP-1/CCL2, KC/CXCL1 and MIP-1α/CCL3, while simultaneously inhibiting neutrophil mobilization from bone marrow, ultimately attenuating innate immune-mediated inflammation (62). In a previous study on a combined alcohol-burn injury model, gut-specific IL-27 downregulation could be therapeutically reversed, with exogenous IL-27 promoting intestinal epithelial proliferation, suppressing proinflammatory cytokines and enhancing IL-10 production, thus collectively restoring intestinal barrier homeostasis (63). Further mechanistic insights emerged from a rat spondyloarthritis study, where recombinant IL-27 ameliorated disease progression by selectively inhibiting IL-17/TNF-producing CD4⁺ T cells (64). This finding was corroborated by cellular coculture experiments showing IL-27's dual capacity to suppress Th17 responses (reducing IL-17 production) while promoting regulatory responses (enhancing IL-10 secretion) in conventional dendritic cell-CD4⁺ T cell interactions. These collective findings highlight the therapeutic potential of IL-27 as a multifunctional immunomodulator capable of resolving inflammation across diverse pathological contexts.

IL-27 generally exhibits pleiotropic effects on T cell subsets, promoting CD8⁺ T and Th1 cell activation, while facilitating the differentiation of type 1 regulatory and follicular helper T cells. Conversely, it suppresses the functional responses of regulatory T (Treg), Th17, Th9 and Th2 cell populations (44,65-70). However, existing literature presents some contradictory findings regarding these immunomodulatory effects (71-73). The precise mechanisms underlying IL-27-mediated T cell regulation in post-stroke conditions remain to be fully elucidated, as T cell differentiation dynamics are influenced by microenvironmental cues. This knowledge gap highlights the need for further mechanistic investigations to elucidate the context-dependent actions of IL-27 in stroke pathophysiology.

Post-stroke neuroinflammatory responses trigger significant upregulation of IL-27 expression in the brain parenchyma, as demonstrated in multiple experimental stroke models (74-76). Clinical evidence further supports the diagnostic potential of IL-27, with serum IL-27α levels showing promise as a predictive biomarker for ischemic stroke occurrence (77). Notably, in patients undergoing emergency endovascular treatment for large vessel occlusion, circulating IL-27 levels were found to correlate with both infarct volume and development of post-ischemic cerebral edema (18). These findings collectively suggest that IL-27 may serve as both a pathophysiological mediator and clinically relevant biomarker in cerebrovascular events.

While existing studies have established that brain injury induces IL-27 upregulation, conclusive evidence for its neuroprotective effects remained elusive until recent preclinical investigations. Emerging data from animal models strongly support IL-27's therapeutic potential in stroke management. In cerebral ischemia-reperfusion models, IL-27 administration demonstrated neuroprotection by activating the gp130/STAT3 signaling pathway to attenuate neuronal apoptosis (16) and modulating cytokine balance through downregulation of proinflammatory mediators (TNF-α, IL-1β and MCP-1), while upregulating anti-inflammatory factors (IL-10 and TGF-β). Notably, in rodent models of hemorrhagic stroke, elevated IL-27 levels were observed in both CNS and peripheral circulation following brain injury (17). Mechanistic studies revealed that IL-27 exerted its beneficial effects through regulating bone marrow neutrophil maturation, suppressing the production of proinflammatory and cytotoxic substances, and promoting the expression of iron-chelating molecules critical for hematoma resolution (17). These multifaceted actions collectively contribute to reduced cerebral edema, enhanced hematoma clearance and improved neurological outcomes (16,17).

Beyond its implications in stroke, emerging evidence underscores IL-27's neuroprotective and regenerative capacities across various neurological disorders. In multiple sclerosis, IL-27 exhibits dual anti-inflammatory and immunomodulatory effects by suppressing Th17 cell differentiation while promoting Treg cell development, positioning it as both a neuroprotective agent and therapeutic candidate (78,79). Conversely, reduced IL-27 levels in patients with Parkinson's disease are associated with neuroinflammation and cognitive decline, although its precise pathogenic role requires further investigation (80). Experimental studies on autoimmune encephalomyelitis have revealed that intrathecal delivery of IL-27-expressing lentiviral vectors attenuates neuroinflammation through two distinct mechanisms: i) Suppressing GM-CSF production in CD4⁺ T cells; and ii) upregulating PD-L1 expression in both CNS-resident and infiltrating myeloid cells (81,82). Retinal degeneration models have further demonstrated IL-27's protective effects, showing increased arginase-1⁺ neuroprotective microglia in the photoreceptor layer alongside elevated IL-27 levels, which collectively enhance photoreceptor survival (83). Additional findings have indicated that IL-27 reduces photoreceptor apoptosis while decreasing retinal concentrations of proinflammatory mediators (IL-12, IL-18 and CCL22) (84). Furthermore, vascular regeneration plays a crucial role in poststroke recovery. Notably, IL-27 promotes the endothelial differentiation of cardiac stem cells (85), suggesting potential angiogenic properties. However, direct evidence for IL-27-mediated cerebrovascular regeneration post-stroke remains to be established. Collectively, these studies highlight IL-27's multifaceted role in stroke pathophysiology, encompassing immunomodulation, neuroprotection and tissue repair. Future research should focus on elucidating the molecular mechanisms underlying these diverse functions of IL-27 in order to fully exploit its therapeutic potential in stroke management.

Recent preclinical studies have established the therapeutic potential of IL-27 in stroke management. Luo et al (16) demonstrated that intraperitoneal administration of recombinant mouse IL-27 (10 µg/kg/day), initiated within 30 min post-middle cerebral artery occlusion (MCAO) and continued daily for 7 days, significantly attenuated ischemia-reperfusion injury. Similarly, Zhao et al (17) reported that intravenous IL-27 treatment (50 ng/kg) initiated 30 min after intracerebral hemorrhage (ICH), followed by subcutaneous administration for 6 consecutive days, improved functional outcomes in ICH models. Emerging evidence has suggested that IL-27 exhibits synergistic effects when combined with other therapeutic modalities. Particularly promising are combination therapies with immune checkpoint inhibitors (anti-PD-1/PD-L1), vaccine-based approaches and vitamin D supplementation (86-88). These findings suggest that combinatorial treatment strategies incorporating IL-27 may represent a novel therapeutic paradigm for stroke. Future clinical translation should focus on optimizing these combination protocols to maximize neuroprotection while minimizing potential side effects.

PANoptosis is a newly identified mode of programmed cell death that activates a series of cellular death processes, such as pyroptosis, apoptosis and necroptosis, initiating potent inflammatory responses after ischemic stroke (89,90). Prior studies demonstrated that activating the TLR4/NF-ĸB signaling pathway induces multiple pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6 (91,92). These pro-inflammatory cytokines trigger cell death by binding to their respective receptors and activating downstream signal transduction (93). Caspase-8 is a PANoptosome component scaffold that regulates the three cell death pathways (pyroptosis, apoptosis and necroptosis) (94). Earlier reports have indicated that the binding of TNF-α to TNFR1 activates caspase-8 and triggers cell death (95). As aforementioned, IL-27 can attenuate inflammation after stroke. Thus, based on the TLR4/NF-ĸB/TNF-α pathway, future studies focused on inflammation-PANoptosis are needed to investigate how IL-27 improves post-stroke.

Ischemic stroke is usually accompanied by neuroinflammation, which is related to unsuitable activation of Nod-like receptor protein 3 (NLRP3) (96). Research has demonstrated that reactive oxygen species (ROS) play a key role in exacerbating the expression of NLRP3 inflammasome, which triggers an inflammatory response that can promote neuronal damage post-stroke. Mitochondrial autophagy, termed mitophagy, involves removing disrupted mitochondria and maintaining cellular homeostasis (97). Upon ischemic injury, mitochondria dysfunction leads to the production of plenty amounts of ROS and reduced clearance. As several studies have reported, obstruction of the mitophagy process results in the insufficient degrading of damaged mitochondria and facilitates the onset of neuroinflammation (98-101). Recent studies found that PTEN-induced kinase 1 and Parkin regulate mitophagy, which is important in attenuating inflammation by cleaning damaged mitochondria (98,99). Sufficient mitophagy will decrease the amounts of pro-inflammatory cytokines, which are the crucial mediators of neuroinflammation after cerebral ischemia (100,101). The previous findings indicated that IL-27 effectively inhibits the inflammatory response by modulating the ROS/NF-ĸB/NLRP3 axis in lung carcinogenesis (102). However, IL-27 mediates mitophagy and inhibits inflammation following cerebral ischemia remains uncovered.

Exosomes, nanoparticles and engineered cells stand out as the main approaches for targeted brain delivery, each with strengths and weaknesses (124). Nanoparticles excel with their potential for large-scale manufacturing and customizable surface modifications, enabling the fine-tuning of size and shape to enhance drug delivery efficacy. They also offer precise control over the release kinetics of medications, accommodating a broad spectrum of drugs, from hydrophilic to lipophilic. However, nanoparticle-based therapies face several limitations, including rapid clearance by the immune system, potential immunogenicity and toxicity, and difficulties in achieving tissue- or cell-specific targeting (125). Consequently, regulatory oversight for nanomedicine is stringent, underscoring the need for meticulous safety and efficacy assessments.

Engineered cells represent a highly promising drug delivery platform, particularly induced pluripotent stem cells and other stem cell types such as totipotent stem cells, unipotent stem cells (126). These modified cells function as sophisticated therapeutic systems, capable of serving as 'living drug factories' that provide sustained therapeutic molecule production while responding to specific microenvironmental cues for controlled drug release. However, this approach has its challenges. The intricacies of cellular manipulation and genetic engineering can be daunting and engender ethical considerations. The host's physiological environment may compromise the cells' survival, proliferation and efficacy post-implantation, and there is the ever-present risk of triggering immune reactions or being eliminated by the immune system (127). Thus, despite their vast potential, the path to clinical realization for engineered cells is fraught with considerable complexity.

Beyond the aforementioned methods, exosomes stand out as a potent candidate for drug delivery. These engineered cellular systems exhibit several therapeutic advantages, including precise tissue targeting capability, low systemic toxicity profiles, diminished immunogenic potential and the capacity to overcome critical biological barriers such as the BBB (128). Additionally, they can transport various bioactive molecules, including proteins, lipids, RNA and DNA. The innate targeting abilities of exosomes, particularly those originating from specific cells, can be significantly amplified through surface modifications, employing techniques of genetic engineering or chemical approaches. However, this delivery method has its challenges. The intricate process of exosome isolation and purification demands considerable resources and sophistication, and their capacity to carry drugs is modest compared with that of other delivery systems (129). Additionally, the state of the donor cells can influence the biogenesis and secretion of exosomes. These complexities highlight the challenges that must be addressed to fully realize the clinical potential of exosomes.

From a translational perspective, while nanoparticle and cellular therapies have reached relative maturity, exosomes exhibit superior safety profiles and targeting precision. Consequently, exosomes may be considered as the optimal delivery vehicle for IL-27. The following section will focus on the strategic implementation of exosome-based delivery systems.

Despite the numerous benefits of IL-27 as a protein-based therapeutic agent, it is crucial to acknowledge its associated limitations. Foremost among these is the substantial cost associated with protein-based medications, including production, transportation and preservation expenses.

IL-27 is considered to be a cytokine, and, in previous research, it did not cause significant toxicity or tissue damage (130). The therapeutic potential of IL-27 is further supported by its demonstrated low toxicity in animal models, which may be attributed to its limited induction of IFN in vivo (131). While IL-27 itself exhibits excellent tolerability with minimal toxicity, recombinant protein formulations may potentially trigger immune responses, leading to allergic reactions and impaired immune tolerance. Recent studies have explored adeno-associated virus (AAV) vectors for IL-27 delivery, demonstrating several advantages (86,132). First, AAV-IL-27 effectively suppresses tumor cell proliferation while maintaining low toxicity. Second, this approach significantly reduces Tregs without inducing autoimmunity. Third, AAV-IL-27 can be administered either locally or systemically while retaining its biological activity (86,87). These findings suggest that optimizing AAV vector delivery systems and incorporating chemical modifications to reduce immunogenicity may enhance both safety and efficacy, thereby expanding therapeutic applications.

Protein-based therapeutics are characterized by their relatively short plasma half-life and susceptibility to enzymatic degradation in vivo, often requiring repeated administration to maintain clinically effective concentrations. Therefore, it is imperative to explore methodologies that can prolong the half-life of protein drugs and attenuate their release rate. Presently, PEGylation stands out as the predominant technique by enhancing the stability of protein drugs and extending their circulation period via augmenting their additional volume (133). Another viable approach involves modifying the Fc region of protein drugs to extend their half-life within the body (134). Furthermore, refining the structure of protein drugs through alterations in their amino acid sequence or the incorporation of stabilizers can increase their stability. These strategies can be implemented individually or in conjunction, thereby enhancing therapeutic effectiveness and diminishing the need for frequent dosing.

The multifaceted nature of IL-27 in immunomodulation has led to controversy over its tumor-suppressive and tumor-promoting activities (135). The majority of previous studies support that IL-27 exhibits antitumor effects by inducing tumor-specific Th1 and cytotoxic T lymphocyte responses, and directly impeding tumor cell proliferation, survival, invasion and angiogenesis (87,88). However, contradictory findings indicate that IL-27 upregulates the transcription factor nuclear factor IL-3 regulated, which synergizes with T-bet to enhance Tim-3 expression. Previous studies have demonstrated that IL-27 signaling is essential to generate Tim-3⁺ exhausted T cells and to facilitate tumor progression. These observations suggest that IL-27-mediated induction of immune checkpoint molecules, including PD-L1 and Tim-3, may promote tumor immune evasion (136,137). Notably, the recent development of SRF388, an IL-27-targeting monoclonal antibody, represents a remarkable therapeutic advance. By blocking IL-27 receptor engagement, SRF388 enhances antitumor immunity within the tumor microenvironment (138). SRF388 has progressed to phase II clinical trials, indicating a promising avenue for therapeutic intervention. These advancements underscore the need of comprehensively assessing the application scenarios and contraindications of IL-27 before considering its utilization as a therapeutic agent for stroke treatment.

IL-27 exhibits a dual role in immune regulation (139). Initially characterized as a pro-inflammatory cytokine (140,141), IL-27 exhibits canonical inflammatory features, including: i) Signal transduction primarily through the JAK/STAT and MAPK/ERK pathways (141,142); ii) production during effector immune responses (137,143); iii) structural similarity to other pro-inflammatory cytokines (IL-35, IL-23, IL-12 and IL-6) (144,145); and iv) capacity to promote T lymphocyte proliferation and activate NK cells (146). The pro-inflammatory mechanism involves sequential events. Binding to the WSX-1 receptor subunit induces rapid STAT3 phosphorylation within 30 min (144), subsequently driving the production of CXCL-10, which is a key mediator of monocyte-derived pro-inflammatory cytokine release (135,143). Conversely, IL-27 also possesses well-documented anti-inflammatory properties that are context-dependent, including the suppression of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-17 and IL-21) and the concurrent upregulation of immunoregulatory IL-10 production (135,139). While current stroke research predominantly focuses on IL-27's anti-inflammatory effects, emerging evidence have revealed that neutrophils recruited during the pro-inflammatory phase may paradoxically contribute to neuroprotection and axonal regeneration (17,147). These findings highlight the need for further investigation into the complex, biphasic mechanisms of IL-27 in post-stroke recovery.

Human stroke comprises ~85% ischemic and ~10% hemorrhagic cases (148). Current preclinical research utilizes several animal models to study ischemic stroke pathogenesis. Global ischemia models, typically induced by permanent vertebral artery ligation and/or transient bilateral common carotid artery occlusion, present several limitations, including technically challenging surgical procedures, frequent seizure induction and lower clinical relevance compared to that of focal ischemia models (149).

Focal ischemia models, particularly MCAO, are superior in replicating human stroke pathophysiology by showing a distinct ischemic penumbra analogous to human stroke, large reproducible infarct volumes and realistic ischemia-reperfusion injury dynamics. However, MCAO models exhibit notable differences from human stroke, including frequent hypothalamic damage (which is rare in humans), inability to simulate thrombolytic reperfusion hemodynamics and infarct volumes (21-45% of ipsilateral hemisphere) that model malignant infarction (39% in humans) rather than typical stroke (4-14% hemisphere involvement) (149,150).

The photothrombotic stroke model offers distinct advantages for investigating cellular and molecular mechanisms of neurodegeneration, neuroprotection and neuroregeneration. However, this model presents several limitations when compared to human ischemic stroke pathology, including pronounced edema formation, minimal penumbral region and inability to replicate ischemia-reperfusion dynamics (149).

The thromboembolic model represents another approach to studying transient focal cerebral ischemia. This technique involves arterial occlusion through either exogenous thrombin administration or injection of macrospheres/microspheres into the internal carotid artery. While clinically relevant to human stroke mechanisms, this model suffers from poor reproducibility in terms of infarct location, size and ischemic duration (149).

Collectively, these experimental models contribute valuable insights into stroke pathophysiology. However, the translational gap remains notable, with numerous therapeutics demonstrating efficacy in animal models but failing to show comparable benefits in human clinical trials. This discrepancy likely derives from two key factors: i) Oversimplified pathophysiology of current animal models compared to the complexity of human stroke and ii) inadequate preclinical evaluation methods that poorly predict clinical outcomes. Addressing these limitations through improved model systems and more rigorous translational paradigms represents a critical need in stroke research.