Pyropia yezoensis glycoprotein regulates antioxidant status and prevents hepatotoxicity in a rat model of D-galactosamine/lipopolysaccharide-induced acute liver failure
- Authors:
- Published online on: February 23, 2016 https://doi.org/10.3892/mmr.2016.4932
- Pages: 3110-3114
Abstract
Introduction
Acute liver failure (ALF), which is characterized by coagulopathy and encephalopathy, is associated with a high mortality rate (1,2). ALF may be induced by alcohol, viral hepatitis, bacteria or hepatotoxic drugs (3), and there is currently no available therapy for ALF other than liver transplantation (4).
D-galactosamine (D-GalN) and lipopolysaccharide (LPS) are often used to generate hepatitis test models (5). Animal models are used in hepatoprotective drug screening, and to elucidate the mechanisms underlying clinical liver dysfunction (6). D-GalN induces a loss of uridine triphosphate via the galactose pathway, and inhibits RNA and protein synthesis (7), thus resulting in hepatic necrosis and apoptosis due to metabolic changes (8). LPS activates liver macrophages, which secrete diverse proinflammatory cytokines, thus inducing hepatic necrosis and reducing the production of antioxidant enzymes (9).
The D-GalN/LPS hepatotoxic model induces inflammatory reactions and oxidative stress within the liver (10,11), due to increased inflammation and expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) (12). iNOS has an important role in drug-induced liver injury (13), and COX-2 has an essential role in D-GalN/LPS-induced inflammation (14). Inflammation leads to the production of reactive oxygen species (ROS), including H2O2, O2− and OH− (15). ROS attack polyunsaturated fatty acids in the cell membrane via lipid peroxidation, and trigger various pathological states, including oxidative stress (16).
Mitogen-activated protein kinases (MAPKs) comprise three major proteins: C-jun NH2-terminal kinase (JNK), p38 MAPK and extracellular signal-regulated kinase (ERK). Phosphorylated MAPK proteins have various roles in oxidative stress and inflammatory diseases (17). In particular, activated JNK has an important role in hepatic injury via activation of the caspase cascade and induction of liver cell necrosis (18).
Pyropia yezoensis is a type of red algae, which has long been considered an important food source in Korea, Japan and China (19). Various previous studies have demonstrated the therapeutic effects of P. yezoensis, including chemoprotec-tive (20), anticancer (21) and anti-inflammatory activities (22). There are currently no studies regarding the antioxidative activities of P. yezoensis glycoprotein (PYGP) against D-GalN/LPS-induced hepatotoxicity. The present study aimed to investigate the anti-inflammatory effects of PYGP against D-GalN/LPS in vivo.
Materials and methods
Preparation of PYGP
P. yezoensis was purchased in 2014 (Suhyup, Seoul, South Korea). P. yezoensis powder (40 g) was diluted with 1 L distilled water and stirred for 4 h at room temperature. The solution was then centrifuged at 3,000 × g and 4°C for 20 min, and vacuum filtered. Triple the volume of ethanol was added to the solution (total quantity of filtrate x 3). After 24 h, the solution was filtered and concentrated using rotary evaporation at 40°C. The concentrated solution was divided into 1.5 ml tubes, freeze-dried, and stored at −70°C until further use.
Experimental animals
Male Sprague-Dawley rats (6 weeks old) were purchased from Samtaco (Osan, South Korea). Animal studies were conducted in accordance with the Animal Ethics Committee of the Pukyong National University (Busan, South Korea). The rats were maintained in the following laboratory conditions: 23±3°C, 12 h light/12 h dark cycle and 50% humidity, with ad libitum access to food and water.
Experimental design
The rats were randomly divided into four groups (n=5/group): Group 1, control rats received distilled water only; group 2, rats received 500 mg/kg/body weight (BW) D-GalN + 10 µg/kg/BW LPS; group 3, rats received 500 mg/kg/BW D-GalN + 10 µg/kg/BW LPS + 150 mg/kg/BW PYGP; and group 4, rats received 500 mg/kg/BW D-GalN + 10 µg/kg/BW LPS + 300 mg/kg/BW PYGP. PYGP was administered orally once a day for 7 days. Hepatotoxicity was induced in the rats by intraperitoneal injection of D-GalN/LPS (Sigma-Aldrich, St. Louis, MO, USA) at a dose of 500 mg/kg/BW D-GalN and 10 µg/kg/BW LPS. The rats were sacrificed under mild ether anesthesia (Duksan Pure Chemicals Co., Ltd., Ansan, South Korea) by decapitation for blood and liver sample collection 6 h after induction of hepatotoxicity.
GOT/GPT measurement
The blood samples were centrifuged at 3,000 × g for 20 min at 4° to collect serum and stored at −20°C until analysis. The activities of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) in the serum samples were determined using an enzymatic analysis kit (Asan Pharmaceuticals, Hwasung, South Korea), according to the manufacturer's protocols. The absorbance was measured at 505 nm using a microplate reader (Benchmark Plus 10730; Bio-Rad Laboratories, Inc., Hercules, CA, USA).
Lipid peroxidation measurements
The liver tissues were added to 1X butyl hydroxyl toluene (Cell Biolabs, Inc., San Diego, CA, USA) and homogenized on ice at 10,000 × g for 5 min to collect the supernatant. According to the Thiobarbituric Acid Reactive Substances (TBARS) Assay kit protocol (Cell Biolabs), 100 µl of sample or malondialdehyde (MDA) standard was added to microcentrifuge tubes and then 100 µl SDS lysis solution was added, mixed thoroughly, incubated for 5 min at room temperature, and 250 µl of TBA reagent added. Each tube was closed, incubated at 95°C for 60 min, removed and then cooled to room temperature in an ice bath for 5 min. All the sample tubes were centrifuged at 842 x g for 15 min, the supernatant removed, 200 µl was transferred, along with 200 µl of MDA standard, to a 96-well microplate compatible with a microplate reader (Benchmark Plus 10730) and the absorbance read at 532 nm.
Antioxidant enzyme measurements
Antioxidant enzyme activities, including catalase (CAT), glutathione (GSH) and glutathione S-transferase (GST), were measured in the liver samples using appropriate kits, according to the manufacturer's protocols (Catalase Assay kit, Glutathione Assay kit and Glutathione S-Transferase Assay kit; all Cayman Chemical Company, Ann Arbor, MI, USA). The absorbance was measured using a microplate reader (Benchmark Plus 10730).
Western blot analysis
Liver tissue samples were homogenized in lysis buffer [150 mM sodium chloride, 50 mM Tris-HCl (pH 7.5), 0.5% sodium deoxycholate, 0.1% sodium dodecyl sulfate (SDS), 1% Triton X-100 and 2 mM ethylenediaminetetra-acetic acid; Intron Biotechnology, Inc., Seongnam, South Korea] containing inhibitors (1 mM Na3 VO4, 1 µg/ml aprotinin, 1 µg/ml leupeptin, 1 µg/ml pepstatin A and 1 mM phenylmethylsulfonyl fluoride; Sigma-Aldrich). Protein concentration was determined using the Bichinchoninic Acid Assay kit (Pierce Biotechnology, Inc., Rockford, IL, USA). Equal protein quantities (20 µg) from each sample were separated by 10–15% SDS-polyacrylamide gel electrophoresis and transferred to a polyvinylidene fluoride membrane (EMD Millipore, Billerica, MA, USA). The membrane was blocked with 1% bovine serum albumin (BSA) in TBST [10 mM Tris-HCl (pH 7.5), 150 mM NaCl and 0.1% Tween 20; USB Corporation, Cleveland, OH, USA]. Subsequently, the membrane was incubated for 4 h at room temperature with the following primary immunoglobulin G antibodies, diluted to 1:1,000 in BSA/TBST: Rabbit anti-rat ERK polyclonal antibody (cat. no. sc-94), rabbit anti-rat phosphorylated (p)-ERK polyclonal antibody (cat. no. sc-7383), mouse anti-rat JNK monoclonal antibody (cat. no. sc-7345), mouse anti-rat p-JNK monoclonal antibody (cat. no. sc-6254), rabbit anti-rat p38 polyclonal antibody (cat. no. sc-7149), mouse anti-rat p-p38 monoclonal antibody (cat. no. sc-7973), mouse anti-rat iNOS polyclonal antibody (cat. no. sc-650), goat anti-rat COX-2 polyclonal antibody (cat. no. sc-1745) and rabbit anti- rat GAPDH polyclonal antibody which served as a loading control (cat. no. sc-25778; all Santa Cruz Biotechnology Inc., Dallas, TX, USA). The membrane was then incubated with peroxidase-conjugated anti-goat (cat. no. 81-1620), anti-mouse (cat. no. 62-6520) and anti-rabbit (cat. no. 65-6120) secondary antibodies (1:10,000; Bethyl Laboratories, Inc., Montgomery, TX, USA) for 1 h at room temperature. Antibody binding was visualized using the Super Signal West Pico Stable Peroxide solution and the Super Signal West Pico Luminol/Enhancer solution (Thermo Fisher Scientific, Inc., Rockford, IL, USA). The signal was developed on Kodak X-ray film (Kodak, Rochester, NY, USA) using a developer and fixer twin pack (Kodak).
Statistical analysis
The results of the present study are presented as the mean ± standard deviation. Data were analyzed using SPSS version 10.0 software (SPSS, Inc., Chicago, IL, USA). Results were validated using analysis of variance and Duncan's multiple range test. P<0.05 was considered to indicate a statistically significant difference.
Results
PYGP suppresses GOT and GPT levels in the serum of D-GalN/LPS-treated rats
GOT and GPT serum levels are important indicators of liver function (23). Injection with D-GalN/LPS elevated the levels of GOT and GPT; however, treatment with 300 mg/kg/BW PYGP significantly reduced these levels (Fig. 1A and B).
Effects of PYGP on D-GalN/LPS-induced oxidative stress and antioxidant enzyme activity
A total of 6 h post-D-GalN/LPS injection, the TBARS levels were determined, which indicate liver tissue lipid peroxidation. As shown in Fig. 2A, TBARS increased significantly following treatment with D-GalN/LPS. Conversely, TBARS levels in the D-GalN/LPS+PYGP 150 and D-GalN/LPS+PYGP 300 groups were markedly decreased. Furthermore, antioxidant enzyme activities were markedly decreased in the D-GalN/LPS group, as compared with in the control group. CAT levels were decreased by ~20%, as compared with the control group. In addition, GST and GSH levels were decreased following D-GalN/LPS treatment, however, levels were restored to control group levels following treatment with PYGP (Fig. 2B–D).
PYGP suppresses D-GalN/LPS-induced MAPK phosphorylation
To investigate whether PYGP was able to modulate MAPK signaling, MAPK protein expression and phosphorylation levels were detected by western blot analysis. The protein expression levels of ERK, JNK and p38 did not differ between the groups. However, the phosphorylation of these proteins increased in the D-GalN/LPS-treated group, as compared with in the control group. In the D-GalN/LPS + PYGP co-treated groups, the phosphorylation levels of these proteins were downregulated (Fig. 3). These results suggest that PYGP may inhibit D-GalN/LPS-induced MAPK phosphorylation.
Effects of PYGP on iNOS and COX-2 protein expression
To confirm the effects of PYGP on inflammation in the rat liver, D-GalN/LPS-induced iNOS and COX-2 protein expression levels were detected. Following treatment with D-GalN/LPS, the protein expression levels were markedly increased; however, treatment with PYGP prior to injection with D-GalN/LPS inhibited D-GalN/LPS-induced iNOS and COX-2 protein expression (Fig. 4). These results indicate that PYGP has an important role in the suppression of D-GalN/LPS-induced iNOS and COX-2 protein expression.
Discussion
Treating rats with a combination of D-GalN and LPS is widely used in studies researching the mechanisms underlying human ALF (24). D-GalN and LPS co-treatment induces greater critical hepatic damage, accompanied by apoptotic and necrotic changes in the liver, which closely resembles human viral hepatitis (25,26). In the present study, administration of D-GalN/LPS increased GOT and GPT serum levels; however, oral administration of PYGP attenuated these levels. These results suggested that D-GalN/LPS was able to induce severe damage to hepatic membranous tissues, and PYGP may prevent this hepatotoxicity.
D-GalN/LPS hepatotoxicity induces ROS production and reduces antioxidant enzyme activity in the liver (27). Furthermore, ROS may cause cell membrane lipid peroxi-dation (28). Oxidative stress is a well-known factor in D-GalN/LPS-induced liver injury. Increased TBARS and conjugated dienes have previously been detected following treatment with D-GalN/LPS (29). In the present study, the levels of TBARS increased in response to D-GalN/LPS treatment; however, co-treatment with D-GalN/LPS and PYGP suppressed hepatic TBARS levels. Antioxidant enzymes, including CAT, GST and GSH are important in D-GalN/LPS hepatotoxicity. CAT catalyzes the dismutation reaction of H2O2, resulting in the formation of H2O and O2 (26). GSH is a substrate of GST, and GST catalyzes the conjugation of GSH with drugs and chemicals (30). In the present study, treatment with D-GalN/LPS significantly reduced the activities of CAT, GST and GSH, as compared with in the control group. Conversely, increased CAT and GST activities, and GSH levels were detected following PYGP treatment. These results suggested that PYGP exerts antioxidative effects against D-GalN/LPS-induced liver injury.
MAPKs comprise ERK, JNK and p38 proteins, which are phosphorylated by D-GalN/LPS (6). These proteins are involved in cell proliferation, differentiation, metabolism, survival and apoptosis (31). In particular, these proteins regulate cytokine production, and the expression of tumor necrosis factor-α and transcription factors (32,33). In the present study, treatment with PYGP significantly suppressed the GalN/LPS-induced phosphorylation of ERK, JNK and p38. These results indicated that GalN/LPS and PYGP co-treatment may reduce MAPK phosphorylation.
Inflammation occurs via various biological pathways. Nitric oxide (NO) production occurs via the iNOS pathway (34); in the cell, increased iNOS protein expression produces large amounts of NO, which increases the prevalence of inflammation (35). In addition, overexpression of NO induces hepatic dysfunction and hepatotoxicity (36). COX-2 is associated with the patho-physiology of inflammatory dysfunction, and the production of prostaglandins and thromboxanes (37), which may lead to hepatic injury (12). In the present study, PYGP pretreatment inhibited GalN/LPS-induced iNOS and COX-2 overexpression.
In conclusion, the present study demonstrated that PYGP may exert protective effects against D-GalN/LPS-induced ALF via inhibition of MAPK phosphorylation and iNOS and COX-2 expression. In addition, PYGP increased the activity of antioxidant enzymes.
Acknowledgments
The present study was supported by the Fishery Commercialization Technology Development Program through the Korean Institute of Planning and Evaluation of Technology in Food, Agriculture, Forestry and Fisheries (iPET) funded by the Ministry of Oceans and Fisheries (grant no. 2012300734).
References
Zhang L, Kang W, Lei Y, Han Q, Zhang G, Lv Y, Li Z, Lou S and Liu Z: Granulocyte colony-stimulating factor treatment ameliorates liver injury and improves survival in rats with D-galactosamine-induced acute liver failure. Toxicol Lett. 204:92–99. 2011. View Article : Google Scholar : PubMed/NCBI | |
Gunning K: Hepatic failure. Anaesthesia & Intensive Care Medicine. 10:124–126. 2009. View Article : Google Scholar | |
Lee WM: Acute liver failure. Semin Respir Crit Care Med. 33:36–45. 2012. View Article : Google Scholar : PubMed/NCBI | |
Matsumoto K, Mizumoto H, Nakazawa K, Ijima H, Funatsu K and Kajiwara T: Hepatic differentiation of mouse embryonic stem cells in a three-dimensional culture system using polyurethane foam. J Biosci Bioeng. 105:350–354. 2008. View Article : Google Scholar : PubMed/NCBI | |
Nakama T, Hirono S, Moriuchi A, Hasuike S, Nagata K, Hori T, Ido A, Hayashi K and Tsubouchi H: Etoposide prevents apoptosis in mouse liver with D-galactosamine/lipopolysaccharide-induced fulminant hepatic failure resulting in reduction of lethality. Hepatology. 33:1441–1450. 2001. View Article : Google Scholar : PubMed/NCBI | |
Chen L, Ren F, Zhang H, Wen T, Piao Z, Zhou L, Zheng S, Zhang J, Chen Y, Han Y, et al: Inhibition of glycogen synthase kinase 3β ameliorates D-GalN/LPS-induced liver injury by reducing endoplasmic reticulum stress-triggered apoptosis. PLoS One. 7:e452022012. View Article : Google Scholar | |
Wang Y, Gao LN, Cui YL and Jiang HL: Protective effect of Danhong injection on acute hepatic failure induced by lipo-polysaccharide and D-galactosamine in mice. Evid Based Complement Alternat Med. 2014:1539022014. View Article : Google Scholar | |
Wilhelm EA, Jesse CR, Roman SS, Nogueira CW and Savegnago L: Hepatoprotective effect of 3-alkynyl selenophene on acute liver injury induced by D-galactosamine and lipopoly-saccharide. Exp Mol Pathol. 87:20–26. 2009. View Article : Google Scholar : PubMed/NCBI | |
Jeong YI, Jung ID, Lee CM, Chang JH, Chun SH, Noh KT, Jeong SK, Shin YK, Lee WS, Kang MS, et al: The novel role of platelet-activating factor in protecting mice against lipopoly-saccharide-induced endotoxic shock. PLoS One. 4:e65032009. View Article : Google Scholar | |
Jin Q, Jiang S, Wu YL, Bai T, Yang Y, Jin X, Lian LH and Nan JX: Hepatoprotective effect of cryptotanshinone from Salvia milt- iorrhiza in D-galactosamine/lipopolysaccharide-induced fulminant hepatic failure. Phytomedicine. 21:141–147. 2014. View Article : Google Scholar | |
Wei L, Ren F, Zhang X, Wen T, Shi H, Zheng S, Zhang J, Chen Y, Han Y and Duan Z: Oxidative stress promotes D-GalN/LPS-induced acute hepatotoxicity by increasing glycogen synthase kinase 3β activity. Inflamm Res. 63:485–494. 2014. View Article : Google Scholar : PubMed/NCBI | |
Huang CC, Lin KJ, Cheng YW, Hsu CA, Yang SS and Shyur LF: Hepatoprotective effect and mechanistic insights of deoxyele-phantopin, a phyto-sesquiterpene lactone, against fulminant hepatitis. J Nutr Biochem. 24:516–530. 2013. View Article : Google Scholar | |
Wen T, Wu ZM, Liu Y, Tan YF, Ren F and Wu H: Upregulation of heme oxygenase-1 with hemin prevents D-galactosamine and lipopolysaccharide-induced acute hepatic injury in rats. Toxicology. 237:184–193. 2007. View Article : Google Scholar : PubMed/NCBI | |
Liong EC, Xiao J, Lau TY, Nanji AA and Tipoe GL: Cyclooxygenase inhibitors protect D-galactosamine/lipopoly-saccharide induced acute hepatic injury in experimental mice model. Food Chem Toxicol. 50:861–866. 2012. View Article : Google Scholar | |
Jaeschke H: Reactive oxygen and mechanisms of inflammatory liver injury. J Gastroenterol Hepatol. 15:718–724. 2000. View Article : Google Scholar : PubMed/NCBI | |
Jaeschke H: Reactive oxygen and mechanisms of inflammatory liver injury: Present concepts. J Gastroenterol Hepatol. 26(Suppl 1): 173–179. 2011. View Article : Google Scholar : PubMed/NCBI | |
Lian LH, Wu YL, Wan Y, Li X, Xie WX and Nan JX: Anti-apoptotic activity of gentiopicroside in D-galactosamine/lipopolysac-charide-induced murine fulminant hepatic failure. Chem Biol Interact. 188:127–133. 2010. View Article : Google Scholar : PubMed/NCBI | |
Wullaert A, Heyninck K and Beyaert R: Mechanisms of crosstalk between TNF-induced NF-kappaB and JNK activation in hepa-tocytes. Biochem Pharmacol. 72:1090–1101. 2006. View Article : Google Scholar : PubMed/NCBI | |
Lee HJ, Kim HC, Vitek L and Nam CM: Algae consumption and risk of type 2 diabetes: Korean National Health And Nutrition Examination Survey in 2005. J Nutr Sci Vitaminol (Tokyo). 56:13–18. 2010. View Article : Google Scholar | |
Choi YH, Kim EY, Mikami K and Nam TJ: Chemoprotective effects of a recombinant protein from Pyropia yezoensis and synthetic peptide against acetaminophen-induced Chang liver cell death. Int J Mol Med. 36:369–376. 2015.PubMed/NCBI | |
Zhang LX, Cai CE, Guo TT, Gu JW, Xu HL, Zhou Y, Wang Y, Liu CC and He PM: Anti-cancer effects of polysaccharide and phycocyanin from Porphyra yezoensis. J Mar Sci Technol. 19:377–382. 2011. | |
Shin ES, Hwang HJ, Kim IH and Nam TJ: A glycoprotein from Porphyra yezoensis produces anti-inflammatory effects in liposaccharide-stimulated macrophages via the TLR4 signaling pathway. Int J Mol Med. 28:809–815. 2011.PubMed/NCBI | |
Maiti R, Jana D, Das UK and Ghosh D: Antidiabetic effect of aqueous extract of seed of Tamarindus indica in streptozotocin-induced diabetic rats. J Ethnopharmacol. 92:85–91. 2004. View Article : Google Scholar : PubMed/NCBI | |
Gilani AH, Yaeesh S, Jamal Q and Ghayur MN: Hepatoprotective activity of aqueous-methanol extract of Artemisia vulgaris. Phytother Res. 19:170–172. 2005. View Article : Google Scholar : PubMed/NCBI | |
Liu LL, Gong LK, Wang H, Xiao Y, Wu XF, Zhang YH, Xue X, Qi XM and Ren J: Baicalin inhibits macrophage activation by lipopolysaccharide and protects mice from endotoxin shock. Biochem Pharmacol. 75:914–922. 2008. View Article : Google Scholar : PubMed/NCBI | |
Vimal V and Devaki T: Hepatoprotective effect of allicin on tissue defense system in galactosamine/endotoxin challenged rats. J Ethnopharmacol. 90:151–154. 2004. View Article : Google Scholar | |
Wang H, Xu DX, Lv JW, Ning H and Wei W: Melatonin attenuates lipopolysaccharide (LPS)-induced apoptotic liver damage in d-galactosamine-sensitized mice. Toxicology. 237:49–57. 2007. View Article : Google Scholar : PubMed/NCBI | |
Bindhumol V, Chitra KC and Mathur PP: Bisphenol A induces reactive oxygen species generation in the liver of male rats. Toxicology. 188:117–124. 2003. View Article : Google Scholar : PubMed/NCBI | |
Lekić N, Cerný D, Hořínek A, Provazník Z, Martínek J and Farghali H: Differential oxidative stress responses to D-galactosamine/lipopolysaccharide hepatotoxicity based on real time PCR analysis of selected oxidant/antioxidant and apoptotic gene expressions in rat. Physiol Res. 60:549–558. 2011. | |
Nordberg J and Arnér ES: Reactive oxygen species, antioxidants and the mammalian thioredoxin system. Free Radic Biol Med. 31:1287–1312. 2001. View Article : Google Scholar : PubMed/NCBI | |
Pearson G, Robinson F, Beers Gibson T, Xu BE, Karandikar M, Berman K and Cobb MH: Mitogen-activated protein (MAP) kinase pathways: Regulation and physiological functions. Endocr Rev. 22:153–183. 2001.PubMed/NCBI | |
Aggarwal BB: Nuclear factor-kappaB: The enemy within. Cancer cell. 6:203–208. 2004. View Article : Google Scholar : PubMed/NCBI | |
Tak PP and Firestein GS: NF-kappaB: A key role in inflammatory diseases. J Clin Invest. 107:7–11. 2001. View Article : Google Scholar : PubMed/NCBI | |
Ishizaki M, Kaibori M, Uchida Y, Hijikawa T, Tanaka H, Ozaki T, Tokuhara K, Matsui K, Kwon AH, Kamiyama Y, et al: Protective effect of FR183998, a Na+/H+ exchanger inhibitor, and its inhibition of iNOS induction in hepatic ischemia-reperfusion injury in rats. Shock. 30:311–317. 2008. View Article : Google Scholar : PubMed/NCBI | |
Xia X, Su C, Fu J, Zhang P, Jiang X, Xu D, Hu L, Song E and Song Y: Role of α-lipoic acid in LPS/d-GalN induced fulminant hepatic failure in mice: Studies on oxidative stress, inflammation and apoptosis. Int Immunopharmacol. 22:293–302. 2014. View Article : Google Scholar : PubMed/NCBI | |
Li R, Yuan C, Dong C, Shunang S and Choi MM: In vivo anti-oxidative effect of isoquercitrin on cadmium-induced oxidative damage to mouse liver and kidney. Naunyn Schmiedebergs Arch Pharmacol. 383:437–445. 2011. View Article : Google Scholar : PubMed/NCBI | |
Serhan CN and Oliw E: Unorthodox routes to prostanoid formation: New twists in cyclooxygenase-initiated pathways. J Clin Invest. 107:1481–1489. 2001. View Article : Google Scholar : PubMed/NCBI |