Protection of photoreceptors by intravitreal injection of the Y‑27632 Rho‑associated protein kinase inhibitor in Royal College of Surgeons rats

  • Authors:
    • Ting Zhang
    • Yantao Wei
    • Xintong Jiang
    • Jingming Li
    • Suo Qiu
    • Shaochong Zhang
  • View Affiliations

  • Published online on: June 3, 2015     https://doi.org/10.3892/mmr.2015.3889
  • Pages: 3655-3661
Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )
Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )


Abstract

Retinitis pigmentosa (RP) is an inherited retinal disease, which is characteristic by degeneration of the rod and cone photoreceptors. The present study aimed to assess the protective effects on photoreceptors of intravitreal injection of Y‑27632, a specific inhibitor of Rho‑associated protein kinase (ROCK), in a Royal College of Surgeons (RCS) rat model. Different concentrations of Y‑27632 (1‑50 mM) were administered by intravitreal injection into the RCS rats. The effects of Y‑27632 were recorded using electroretinography (ERG), measuring the thicknesses of the retinal outer nuclear layer (ONL) and examination of apoptotic markers using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and western blot analysis. Treatment of the eyes with Y27632 at 10 or 50 mM, led to a 30% increase in a‑ and b‑wave amplitudes in ERG, and an increase in ONL thickness by 10%, compared with the 1 mM Y‑27632‑treated and vehicle (phosphate‑buffered saline; PBS)‑treated groups. In addition, eyes treated with 10 mM Y27632 exhibited a 90% decrease in TUNEL‑positive cells, accompanied by decreased protein expression levels of active caspase 3 and Bax by 50%, and a 90% increase in the ratio of Bcl‑2/Bax, compared with the PBS‑treated groups. These data suggested that Y‑27632 protected retinal function by inhibiting the apoptosis of photoreceptor cells in the RCS rat model. The present study demonstrated for the first time, to the best of our knowledge, to report the use of Y‑27632 for protection against RP in an RCS rat model. Y‑27632 may be a potential candidate for the treatment of human RP.

Introduction

Retinitis pigmentosa (RP) describes a group of inherited retinal diseases, characterized by the progressive loss of photoreceptors, resulting in night blindness and visual field constriction (1). The worldwide prevalence of RP is ~1/4,000, which affects >1 million individuals. The family of disease that are pheno-typically recognized as RP consists of >150 genotypically distinct entities (2). Despite the different genotypes, the loss of vision in RP is associated with the death of photoreceptor cells. Previous studies have indicated that apoptosis is the dominant mechanism of photoreceptor death in Royal College of Surgeons (RCS) rats, which are one of the animal models of RP (3,4). Portera-Cailliau et al (5) suggested that retinal degeneration may be slowed by interfering with apoptotic mechanisms. Therefore, therapeutic strategies, which target a common mechanism of photoreceptor death among a multitude of genotypes may offer a broad clinical application for the treatment of RP.

It has been well-documented that the small GTP-binding protein, Rho, contributes to the regulation of neurite outgrowth (68) and apoptosis (9) in neuronal cells. In addition, Rho-associated protein kinase (ROCK), one of the key effectors of Rho, is involved in growth factor signaling (10,11), the regulation of apoptosis (12) and cell survival (13). These proteins are abundantly expressed in various types of cell (14), including those in the retina (1517). Previous reports have demonstrated that the activation of RhoA, one of the Rho family GTPases, can induce retinal degeneration (18). The intravitreal administration of HA-1077 or Y-27632, which are specific ROCK inhibitors, has been observed to improve retinal function in a mouse model of Huntington's Disease with progressive retinopathy (19), and to rescue retinal ganglion cells in rat models of diabetes and transient retinal ischemia (18). The present study hypothesized that the photoreceptor degeneration in RP may be treated by intravitreal administration of Y-27632, via the inhibition of apoptosis in RCS rats. This is the first time, to the best of our knowledge, that Y-27632 that has been used for RP in RCS rat models.

Materials and methods

Animal model

A total of 20 male and 20 female dystrophic RCS rats (rdy+p+; 21 days-old), obtained from the Third Military Medical University (Xian, China) were used in the present study. The rats were housed in cages (one rat/cage), maintained in standard conditions (room temperature 23±2C; relative humidity 60±10%; 12 h light/dark cycle), and were fed a standard laboratory diet with ad libitum access to water. Prior to all experiments, the ocular surface integrity was examined by slit-lamp microscope (OMS-85; Topcon, Tokyo, Japan). At the point of intravitreal injection, development of the rods and cones in the rats had been completed (20) and electroretinograph (ERG) responses were normal amplitudes (21). The rats were anesthetized and sacrificed by intraperitoneal injection of 10% chloral hydrate (China Otsuka Pharmaceutical Co., Ltd., Tianjin, China), following which the eyes were immediately enucleated. The animals were maintained and treated in accordance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research and the present study was approved by the animal ethics committee of Zhongshan Ophthalmic Center, Sun Yat-sen University (Guanzhou, China; approval no. ID:2012-12).

Experimental design

A total of 40 RCS rats were used for ERG recording and measurements of the ONL thickness. The rats were divided into four groups (n=10 in each group): 1 mM Y27632 intravitreal injection, 10 mM Y27632; 50 mM Y27632 and phosphate-buffered saline (PBS) control groups. A total of 20 RCS rats were used for terminal deoxynucleotidyl transferase-mediated biotinylated-dUTP nick-end labeling (TUNEL) assays and to determine the expression levels of active caspase 3, Bax and Bcl-2. These rats were divided into two groups (n=10 in each group): A 10 mM Y27632 and a PBS (1 µl) control group.

Y-27362 administration

The dosage effects of Y-27632 (Wako Pure Chemicals Industries, Ltd., Osaka, Japan) on the morphology and function of the retina were assessed by injecting 1, 10 or 50 mM Y-27632 into the vitreous (0.1, 1 and 5 mM final concentrations, respectively, on day 21 (n=10). The doses were selected based on the successful neuroprotection of retinal ganglion cells, demonstrated using a dose of 100 nmol/eye, which was equal to the final concentration of 1 mM used in the present study (18,22). The inhibitory effects of Y-27632 on the apoptosis of the photoreceptor were analyzed by injecting 10 mMY-27632 on day 21 (n=10) (20). Each concentration of Y-27632 was diluted in PBS to the same final volume (1 µl) for the intravitreal injection. The control group was intravitreally injected with 1 µl PBS, instead of Y-27632 (n=10).

Intravitreal injections were performed under an operating microscope (OPMI VISU 200; Carl Zeiss AG, Oberchoken, Germany), using a microsyringe (Hamilton, Reno, NV, USA) with a 30-gauge needle (Hamilton). The needle was inserted ~1 mm behind the corneal limbus.

ERG recording

The ERG recording was performed on day 28, according to Mandal et al (23). ERGs were monitored using a Neuropack α electophysiological recorder (Nihon Kohden Corp., Tokyo, Japan). Briefly, following 12 h dark adaptation under dim red light, the animals were anesthetized by intramuscular administration of a mixture of 100 mg/kg ketamine and 10 mg/kg xylazine (Shenyang Sinqi Pharmaceutical Co., Ltd., Shenyang, China). The pupils were dilated with 0.5% tropicamide (Shenyang Sinqi Pharmaceutical Co., Ltd.) and body temperature was maintained at ~37°C with a heating pad (Beijing Gaoshiyuanwang Technologies Co., Ltd., Beijing, China). ERGs were recorded from each eye using a gold loop electrode (Beijing Gaoshiyuanwang Technologies Co., Ltd.) on the corneal surface, maintained with Lacrigel lubricating ointment (Laboratoires Europhta, Monaco). A reference electrode was attached to the shaven skin on the head and a ground electrode was clipped to the animal skin of the tail. The amplitudes of a-wave and b-wave were measured from the average of three responses by a set of three flashes of stimulation, using two flash intensities, 1,000 and 2,000 cd·s/m2.

Measurement of the ONL thickness

Following the ERG recording, the animals were sacrificed by carbon dioxide asphyxiation. The animal's eyes were removed, fixed with 4% paraformaldehyde and embedded in paraffin. Sections (5 µm thick) of eyeballs were cut along the vertical meridian through the optic nerve head. The sections were dewaxed with xylene, rehydrated with anhydrous ethanol and stained with hematoxylin and eosin (Sigma-Aldrich, St. Louis, MO, USA). The ONL thickness was measured under a light microscope (Axioplan2; Carl Zeiss Meditec, Inc., Jena, Germany). Measurements were made at 300 µm intervals in nine defined areas, starting at the optic nerve, and extending toward the superior and inferior ora serrata, according to LaVail et al (24). The ONL thickness measurements were averaged within each group to provide a single value for statistical analysis.

TUNEL assay

A TUNEL assay was performed to detect apoptosis on the cryosections of the rat eyes using the in situ Cell Death Detection TMR Red kit (Roche Diagnostics, Indianapolis, IN, USA). For staining of the sections, the samples were permeabilized for 2 min in cold PBS, containing 0.1% Triton X-100 and were subsequently incubated at 37°C in the TUNEL reaction mix, which contained nucleotides and terminal deoxynucleotidyl transferase (TdT). Incubation in the absence of the TdT enzyme was performed as a negative vehicle control. The sections were subsequently mounted (VECTASHIELD mounting medium with DAPI; Vector Laboratories, Inc., Burlingame, CA, USA), and visualized by confocal microscopy (LSM510; Carl Zeiss AG). The apoptotic index of the ONL was calculated as the number of TUNEL-positive nuclei / number of photoreceptor cell nuclei, as previously described by Kyger et al (25).

Western blot analysis

The rat retinas were dissected using a surgical microscope and lysed in buffer, containing 1 M Tris-HCl (pH 7.5), 1% Triton X-100, 1% nonidet P-40, 10% sodium dodecyl sulfate, 0.5% sodium deoxycholate, 0.5 M EDTA, 10 µg/ml leupeptin, 10 µg/ml aprotinin, and 1 mM phenylmethylsulfonyl fluoride. The retinal protein concentrations were determined using a bicinchoninic acid assay (Pierce Biotechnology, Inc., Rockford, IL, USA). The retinal proteins (25 µg) were separated using SDS-PAGE and transferred onto a polyvinylidine difluoride filter membrane (Millipore, Bedford, MA, USA). The membranes were then blocked with skimmed milk at room temperature for 2 h. Subsequently, the membrane was incubated with primary polyclonal antibodies against active caspase 3 (anti-mouse; 1:1,000; Santa Cruz Biotechnology, Inc., Dallas, TX, USA), Bcl-2 (anti-mouse; 1:1,000; Sigma-Aldrich), Bax (anti-rabbit; 1:1,000; Cell Signaling Technology, Inc., Danvers, MA, USA) or β-actin (anti-mouse, 1:1,000; Santa Cruz Biotechnology, Inc.) at 4°C overnight. The membrane was subsequently incubated with goat-anti-rabbit or goat-anti-mouse conjugated horseradish peroxidase secondary antibody (1:2,000; Southern-Biotech, Birmingham, AL, USA) for 2 h at room temperature. The membranes were visualized using an enhanced chemiluminescence system (Pierce Biotechnology, Inc.).

Statistical analyses

One-way analysis of variance, followed by Bonferroni's multiple-comparison test was used for statistical analyses. The data are expressed as the mean ± standard error of the mean. Statistical analyses were conducted using SPSS version 16.0 (SPSS Inc., Chicago, IL, USA). P<0.05 was considered to indicate a statistically significant difference.

Results

Protective effect of Y-27632 on the retinal function of RCS rats

To investigate the effect on the retinal function of intravitreal injection of Y-27632, the present study analyzed the scotopic mixed rod-cone ERG a- and b-wave amplitudes 1 week following injection. Treatment with 10 or 50 mM Y-27632 significantly increased the a- and b-wave amplitudes by ~30%, compared with the 1 mM Y-27632-treated and control groups (P<0.01). However, no significant changes were observed between the 1 mM Y-27632-treated and control groups (P>0.05), or between the 10 mM and 50 mM Y-27632-treated groups (P>0.05; Fig. 1A–C).

Protective effect of Y-27632 on the ONL thickness of RCS rats

The present study then investigated whether retinal morphology was altered following Y-27632 injection by analyzing the ONL thickness. No significant differences were observed in the ONL thickness between the control and 1 mM Y-27632-treated eyes, however, the ONL thicknesses in the 10 and 50 mM Y-27632-treated eyes were significantly higher than those in the control and 1 mM Y-27632-treated eyes 1 week post-injection. No significant differences were observed between the ONL thicknesses of the eyes in the 10 and 50 mM Y-27632 groups (Fig. 2A and B). According to these findings, the dosage of 10 mM Y-27632 was used as the minimum and effective concentration in the subsequent experiments.

Protective effect of Y-27632 on photoreceptor apoptosis in RCS rats

To determine whether Y-27632 affected the apoptosis of photoreceptors in RCS rats, in situ labeling using a TUNEL assay was performed in the retinal tissues of the rats. An abundance of TUNEL-positive cells (red) were detected in the retina of the control group 1 week post-injection. However, the number of TUNEL-positive cells in the 10 mM Y-27632-treated eyes was markedly lower. In each group, the TUNEL-positive cells were present only in the ONL. The administration of 10 mM Y-27632 significantly decreased the apoptosis of photoreceptors compared with the PBS-injected control group (P<0.01), as shown in Fig. 3A and B).

Y-27632 increases the protein expression of Bcl-2 and decreases the protein expression levels of caspase 3 and Bax in RCS rats

The present study investigated the effect of Y-27632 on the expression levels of caspase 3, Bax and Bcl-2 in the RCS rat retina via western blot analysis. The protein expression levels of active caspase 3 and Bax in the 10 mM Y-27632-treated retinas markedly decreased 1 week post-injection. However, administration of 10 mM Y-27632 markedly increased the protein expression of Bcl-2. Furthermore the Bcl-2/Bax ratio in the 10 mM Y-27632-treated retinas was 10-fold higher than that in the PBS-treated retinas (Fig. 4A and B). The difference in levels of active caspase 3, Bax and Bcl-2, and the Bcl-2/Bax ratio were statistically significant between the 10 mM Y-27632-treated and PBS-treated groups (P<0.01; Fig. 4C–F).

Discussion

Previous studies have demonstrated that RhoA is sufficient to induce the neuronal excitotoxic pathway, which indicates that Rho is an essential component of the excitotoxic neuronal cell death pathway (26). It is understood that treatment with Y-27632 inhibits neurodegeneration in models of huntingtin degradation (27,28), Parkinson's disease (29) and Alzheimer's disease (30). In addition, a previous study demonstrated that HA-1077, or Fasudil, which is another selective inhibitor of ROCK, is an efficacious therapeutic molecule that slows the progression of photoreceptor degeneration (19). Furthermore, it has been reported that Y26732-supplemented culture media reduces dissociation-induced apoptosis in vivo and in vitro. Koyanagi et al (31) revealed that Y26732 rescues transplanted neural precursor cells from apoptosis in a mouse transplantation model. Claassen et al (32) also demonstrated that supplementation of cell culture media with 10 µM Y-26732 efficiently reduced apoptosis and increased the survival and proliferation of dissociated human embryonic stem cell-derived neural progenitor cells in vitro. Collectively, these findings suggested that Y-26732 can be used for the treatment of degeneration of photoreceptors in RP.

The present study demonstrated that intravitreal injection of the Y-27632 ROCK inhibitor prevented photoreceptor degeneration in RCS rats. Human RP can be diagnosed by changes in ERG. In the scotopic flash ERG, the a-wave primarily represents the mixed function of cones and rods, and the b-wave predominantly reflects light-induced depolarization of ONL bipolar cells, but may be altered by the activity of other cells, including the responses of Müller cells (33). The present study demonstrated significant preservation of a- and b-wave amplitudes in the ERG assays in the retinal tissues of rats treated with 10 and 50 mM Y-27632 1 week post-injection. In addition, the numbers of cells in the ONL in the 10 and 50 mM Y-27632-treated groups were significantly higher, compared with those in the 1 mM-treated and the vehicle-injected eyes. The present study also demonstrated that no preservation of photoreceptors occurred in the 1 mM Y-27632-treated group, whereas 10 and 50 mM Y-27632 did preserve the photoreceptors. These findings indicated that, for the preservation of photoreceptors in RCS rats, 10 or 50 mM Y-27632 provided an effective dose. Therefore, a minimum and effective concentration of 10 mM Y-27632, was used in the subsequent experiments.

These findings were supported by the effect on the apoptosis of photoreceptors. Apoptosis is the predominant mechanism of photoreceptor degeneration in RCS rats (4). As described previously in RCS rats (34), the photoreceptor outer segments are irregularly aligned, with vacuolation in the inner segments and TUNEL-positive cells in 50% of the outer retinal layers on day 30 (4). The observations in the present study using PBS-injected RCS rats were consistent with these findings. By contrast, when 10 mM Y-27632 was administered intravitreally, the number of TUNEL-positive cells (red) in the outer retina was significantly reduced.

A number of studies have suggested that activation of the caspase family is important in the execution of apoptotic events (35,36). The activation of caspase-like proteases is important in the apoptosis of photoreceptors in RCS rats (37). In the present study, western blot analysis revealed that the expression of active caspase 3 in the retina of the RCS rats was decreased following treatment with 10 mM Y-27632. The Bcl-2 family of proteins, consisting of pro-apoptotic Bax and anti-apoptotic Bcl-2 members, is important in the regulation of neuronal apoptosis. Apoptosis can be inhibited by the inhibition of the expression of the apoptosis-associated genes, including Bax, or by the overexpression of Bcl-2 (38,39). Previous studies have demonstrated that Bax is upregulated in photoreceptors and Bcl-2 was not downregulated in RCS rat retinas on day 28 compared with day 21 (40). The role of the Bcl-2 family in the apoptotic process of photoreceptors remains to be elucidated (41). The present study demonstrated that the protein expression of Bcl-2 and the ratio of Bcl-2/Bax were increased, while the protein expression of Bax was reduced in the 10 mM Y-27632-treated retinas compared with the PBS-treated retinas on day 28. Taken together, these findings indicated that Y-27632 may inhibit the apoptosis of photoreceptors via a caspase-dependent pathway in the RCS rat, and the Bcl-2 family may be involved in this process.

In conclusion, the present study demonstrated that a single intravitreal injection of Y-27632 had a significant protective effect on photoreceptor degeneration, morphologically and functionally, by inhibiting the apoptosis of photoreceptors in the RCS rat retinas. Therefore, the intravitreal administration of Y-27632 is a potential candidate as a novel therapeutic strategy for photoreceptor degeneration, including RP. However, further investigation of the underlying mechanisms of Y-27632 on photoreceptor protection is required to improve the efficiency of protection for clinical therapeutic use.

Acknowledgments

This study was supported by grants from the National Natural Science Foundation of China (no. 81170866) and the Guangdong Science and Technology Plan Project (no. 2012B031800380).

References

1 

Dryja TP and Li T: Molecular genetics of retinitis pigmentosa. Hum Mol Genet. 4(Spec No): 1739–1743. 1995.PubMed/NCBI

2 

van Soest S, Westerveld A, de Jong PT, Bleeker-Wagemakers EM and Bergen AA: Retinitis pigmentosa: defined from a molecular point of view. Surv Ophthalmol. 43:321–334. 1999. View Article : Google Scholar : PubMed/NCBI

3 

Travis GH: Mechanisms of cell death in the inherited retinal degenerations. Am J Hum Genet. 62:503–508. 1998. View Article : Google Scholar : PubMed/NCBI

4 

Tso MO, Zhang C, Abler AS, et al: Apoptosis leads to photoreceptor degeneration in inherited retinal dystrophy of RCS rats. Invest Ophthalmol Vis Sci. 35:2693–2699. 1994.PubMed/NCBI

5 

Portera-Cailliau C, Sung CH, Nathans J and Adler R: Apoptotic photoreceptor cell death in mouse models of retinitis pigmentosa. Proc Natl Acad Sci USA. 91:974–978. 1994. View Article : Google Scholar : PubMed/NCBI

6 

Arakawa Y, Bito H, Furuyashiki T, et al: Control of axon elongation via an SDF-1alpha/Rho/mDia pathway in cultured cerebellar granule neurons. J Cell Biol. 161:381–391. 2003. View Article : Google Scholar : PubMed/NCBI

7 

van Galen EJ and Ramakers GJ: Rho proteins, mental retardation and the neurobiological basis of intelligence. Prog Brain Res. 147:295–317. 2005. View Article : Google Scholar

8 

Woo S and Gomez TM: Rac1 and RhoA promote neurite outgrowth through formation and stabilization of growth cone point contacts. J Neurosci. 26:1418–1428. 2006. View Article : Google Scholar : PubMed/NCBI

9 

Dubreuil CI, Winton MJ and McKerracher L: Rho activation patterns after spinal cord injury and the role of activated Rho in apoptosis in the central nervous system. J Cell Biol. 162:233–243. 2003. View Article : Google Scholar : PubMed/NCBI

10 

Burridge K and Wennerberg K: Rho and Rac take center stage. Cell. 116:167–179. 2004. View Article : Google Scholar : PubMed/NCBI

11 

Ali TK, Al-Gayyar MM, Matragoon S, et al: Diabetes-induced peroxynitrite impairs the balance of pro-nerve growth factor and nerve growth factor and causes neurovascular injury. Diabetologia. 54:657–668. 2011. View Article : Google Scholar

12 

Linseman DA and Loucks FA: Diverse roles of Rho family GTPases in neuronal development, survival and death. Front Biosci. 13:657–676. 2008. View Article : Google Scholar

13 

Aznar S and Lacal JC: Rho signals to cell growth and apoptosis. Cancer Lett. 165:1–10. 2001. View Article : Google Scholar : PubMed/NCBI

14 

Ridley AJ: Rho family proteins: coordinating cell responses. Trends. Cell Biol. 11:471–477. 2001. View Article : Google Scholar

15 

Yonemura S, Hirao-Minakuchi K and Nishimura Y: Rho localization in cells and tissues. Exp Cell Res. 295:300–314. 2004. View Article : Google Scholar : PubMed/NCBI

16 

Kitaoka Y, Kitaoka Y, Kumai T, et al: Involvement of RhoA and possible neuroprotective effect of fasudil, a Rho kinase inhibitor, in NMDA-induced neurotoxicity in the rat retina. Brain Res. 1018:111–118. 2004. View Article : Google Scholar : PubMed/NCBI

17 

Mitchell DC, Bryan BA, Liu JP, et al: Developmental expression of three small GTPases in the mouse eye. Mol Vis. 13:1144–1153. 2007.PubMed/NCBI

18 

Al-Gayyar MM, Mysona BA, Matragoon S, et al: Diabetes and overexpression of proNGF cause retinal neurodegeneration via activation of RhoA pathway. PLoS One. 8:e546922013. View Article : Google Scholar : PubMed/NCBI

19 

Li M, Yasumura D, Ma AA, et al: Intravitreal administration of HA-1077, a ROCK inhibitor, improves retinal function in a mouse model of huntington disease. PLoS One. 8:e560262013. View Article : Google Scholar : PubMed/NCBI

20 

Huang YM, Yin ZQ, Liu K and Huo SJ: Temporal and spatial characteristics of cone degeneration in RCS rats. Jpn J Ophthalmol. 55:155–162. 2011. View Article : Google Scholar : PubMed/NCBI

21 

Sauvé Y, Lu B and Lund RD: The relationship between full field electroretinogram and perimetry-like visual thresholds in RCS rats during photoreceptor degeneration and rescue by cell transplants. Vision Res. 44:9–18. 2004. View Article : Google Scholar

22 

Hirata A, Inatani M, Inomata Y, et al: Y-27632, a Rho-associated protein kinase inhibitor, attenuates neuronal cell death after transient retinal ischemia. Graefes Arch Clin Exp Ophthalmol. 246:51–59. 2008. View Article : Google Scholar

23 

Mandal MN, Patlolla JM, Zheng L, et al: Curcumin protects retinal cells from light-and oxidant stress-induced cell death. Free Radic Biol Med. 46:672–679. 2009. View Article : Google Scholar : PubMed/NCBI

24 

LaVail MM, Sidman RL and Gerhardt CO: Congenic strains of RCS rats with inherited retinal dystrophy. J Hered. 66:242–244. 1975.PubMed/NCBI

25 

Kyger M, Worley A and Adamus G: Autoimmune responses against photoreceptor antigens during retinal degeneration and their role in macrophage recruitment into retinas of RCS rats. J Neuroimmunol. 254:91–100. 2013. View Article : Google Scholar :

26 

Satoh S, Utsunomiya T, Tsurui K, et al: Pharmacological profile of hydroxy fasudil as a selective rho kinase inhibitor on ischemic brain damage. Life Sci. 69:1441–1453. 2001. View Article : Google Scholar : PubMed/NCBI

27 

Bauer PO and Nukina N: Enhanced degradation of mutant huntingtin by rho kinase inhibition is mediated through activation of proteasome and macroautophagy. Autophagy. 5:747–748. 2009. View Article : Google Scholar : PubMed/NCBI

28 

Bauer PO, Wong HK, Oyama F, et al: Inhibition of Rho kinases enhances the degradation of mutant huntingtin. J Biol Chem. 284:13153–13164. 2009. View Article : Google Scholar : PubMed/NCBI

29 

Rodriguez-Perez AI, Dominguez-Meijide A, Lanciego JL, Guerra MJ and Labandeira-Garcia JL: Inhibition of Rho kinase mediates the neuroprotective effects of estrogen in the MPTP model of Parkinson's disease. Neurobiol Dis. 58:209–219. 2013. View Article : Google Scholar : PubMed/NCBI

30 

Petratos S, Li QX, George AJ, et al: The beta-amyloid protein of Alzheimer's disease increases neuronal CRMP-2 phosphorylation by a Rho-GTP mechanism. Brain. 131:90–108. 2008. View Article : Google Scholar

31 

Koyanagi M, Takahashi J, Arakawa Y, et al: Inhibition of the Rho/ROCK pathway reduces apoptosis during transplantation of embryonic stem cell-derived neural precursors. J Neurosci Res. 86:270–280. 2008. View Article : Google Scholar

32 

Claassen DA, Desler MM and Rizzino A: ROCK inhibition enhances the recovery and growth of cryopreserved human embryonic stem cells and human induced pluripotent stem cells. Mol Reprod Dev. 76:722–732. 2009. View Article : Google Scholar : PubMed/NCBI

33 

Mojumder DK, Sherry DM and Frishman LJ: Contribution of voltage-gated sodium channels to the b-wave of the mammalian flash electroretinogram. J Physiol. 586:2551–2580. 2008. View Article : Google Scholar : PubMed/NCBI

34 

Nakayama AY, Harms MB and Luo L: Small GTPases Rac and Rho in the maintenance of dendritic spines and branches in hippocampal pyramidal neurons. J Neurosci. 20:5329–5338. 2000.PubMed/NCBI

35 

Peng Y, Zhang J, Xu H, He J, Ying X and Wang Y: Neuroprotective effect of protease-activated receptor-2 in the hypoxia-induced apoptosis of rat RGC-5 cells. J Mol Neurosci. 50:98–108. 2013. View Article : Google Scholar

36 

Wu X, Jin W, Liu X, et al: Cyclic AMP response element modulator-1 (CREM-1) involves in neuronal apoptosis after traumatic brain injury. J Mol Neurosci. 47:357–367. 2012. View Article : Google Scholar : PubMed/NCBI

37 

Katai N, Kikuchi T, Shibuki H, et al: Caspaselike proteases activated in apoptotic photoreceptors of Royal College of Surgeons rats. Invest Ophthalmol Vis Sci. 40:1802–1807. 1999.PubMed/NCBI

38 

Hafezi F, Steinbach JP, Marti A, et al: The absence of c-fos prevents light-induced apoptotic cell death of photoreceptors in retinal degeneration in vivo. Nat Med. 3:346–349. 1997. View Article : Google Scholar : PubMed/NCBI

39 

Shimizu S, Eguchi Y, Kamiike W, Matsuda H and Tsujimoto Y: Bcl-2 expression prevents activation of the ICE protease cascade. Oncogene. 12:2251–2257. 1996.PubMed/NCBI

40 

Katai N, Yanagidaira T, Senda N, Murata T and Yoshimura N: Expression of c-Jun and Bcl-2 family proteins in apoptotic photoreceptors of RCS rats. Jpn J Ophthalmol. 50:121–127. 2006. View Article : Google Scholar : PubMed/NCBI

41 

Chen J, Flannery JG, LaVail MM, Steinberg RH, Xu J and Simon MI: bcl-2 overexpression reduces apoptotic photoreceptor cell death in three different retinal degenerations. Proc Natl Acad Sci USA. 93:7042–7047. 1996. View Article : Google Scholar : PubMed/NCBI

Related Articles

Journal Cover

September-2015
Volume 12 Issue 3

Print ISSN: 1791-2997
Online ISSN:1791-3004

Sign up for eToc alerts

Recommend to Library

Copy and paste a formatted citation
x
Spandidos Publications style
Zhang T, Wei Y, Jiang X, Li J, Qiu S and Zhang S: Protection of photoreceptors by intravitreal injection of the Y‑27632 Rho‑associated protein kinase inhibitor in Royal College of Surgeons rats. Mol Med Rep 12: 3655-3661, 2015
APA
Zhang, T., Wei, Y., Jiang, X., Li, J., Qiu, S., & Zhang, S. (2015). Protection of photoreceptors by intravitreal injection of the Y‑27632 Rho‑associated protein kinase inhibitor in Royal College of Surgeons rats. Molecular Medicine Reports, 12, 3655-3661. https://doi.org/10.3892/mmr.2015.3889
MLA
Zhang, T., Wei, Y., Jiang, X., Li, J., Qiu, S., Zhang, S."Protection of photoreceptors by intravitreal injection of the Y‑27632 Rho‑associated protein kinase inhibitor in Royal College of Surgeons rats". Molecular Medicine Reports 12.3 (2015): 3655-3661.
Chicago
Zhang, T., Wei, Y., Jiang, X., Li, J., Qiu, S., Zhang, S."Protection of photoreceptors by intravitreal injection of the Y‑27632 Rho‑associated protein kinase inhibitor in Royal College of Surgeons rats". Molecular Medicine Reports 12, no. 3 (2015): 3655-3661. https://doi.org/10.3892/mmr.2015.3889