Objective To investigate the therapeutic effect of Gypenoside L(Gyp-L)on diabetic retinopathy(DR)rats and its effect on the p38 mitogen-activated protein kinase(MAPK)signaling pathway.Methods Rats were divided into 6 groups(n=12):blank group,model group,low,medium,high dose group and combination group.The blank group was normal control rats,and the other groups were DR rat models.Rats in the blank group and model group were intragastrically administered with sodium carboxymethyl cellulose.Rats in the low,medium and high dose group were ga-vaged with 50,100,and 200 mg·kg-1·d-1 of Gypenoside L solution,respectively.Rats in the combination group were gavaged with 200 mg·kg-1·d-1 of Gypenoside L solution,and 2 mg·kg-1·d-1 of p38 MAPK agonist Anisomycin was in-jected into the tail vein.The rats in each group were gavaged with a volume of 2 mL per day for a total treatment period of 4 weeks.After the treatment,fundus photography was performed on the rats in each group,and retinal tissues were stained with hematoxylin and eosin(HE).Fasting blood glucose was measured using a Roche blood glucose meter,and se-rum insulin levels were measured using an ELISA kit.Retinal superoxide dismutase(SOD),catalase(CAT),glutathione peroxidase(GSH-Px),malondialdehyde(MDA),tumor necrosis factor-α(TNF-α),interleukin(IL)-1 β,and IL-6 levels were measured according to the instructions of the kit.Western blot was used to detect the protein levels of p38 MAPK,p-p38 MAPK,p65 nuclear factor-κB(NF-κB),p-p65 NF-κB,inducible nitric oxide synthase(iNOS),and cyclooxygenase(COX-2)in the retina.Results Compared with the model group,the blood glucose level was decreased,the serum insu-lin level was increased,the fundus neovascularization was reduced,the retinal damage was alleviated,the retinal SOD,CAT and GSH-Px levels were increased,the MDA level was decreased,the TNF-α,IL-1β and IL-6 levels were decreased,and the p-p38 MAPK,p-p65 NF-κB,iNOS and COX-2 protein levels were decreased in the low,medium and high dose group(all P＜0.05).Compared with the high dose group,the blood glucose level in the combination group was increased,the serum insulin level was decreased,the fundus neovascularization increased,the retinal damage was aggravated,the ret-inal SOD,CAT and GSH-Px levels were decreased,the MDA level was increased,the TNF-α,IL-1[3 and IL-6 levels were in-creased,and the p-p38 MAPK,p-p65NF-κB,iNOS and COX-2 protein levels were increased(all P＜0.05).Conclusion This study shows that Gypenoside L can reduce inflammation and oxidative stress by blocking the p38 MAPK signaling path-way,thereby playing a role in the treatment of DR.

Objective To investigate the therapeutic effect of Gypenoside L(Gyp-L)on diabetic retinopathy(DR)rats and its effect on the p38 mitogen-activated protein kinase(MAPK)signaling pathway.Methods Rats were divided into 6 groups(n=12):blank group,model group,low,medium,high dose group and combination group.The blank group was normal control rats,and the other groups were DR rat models.Rats in the blank group and model group were intragastrically administered with sodium carboxymethyl cellulose.Rats in the low,medium and high dose group were ga-vaged with 50,100,and 200 mg·kg-1·d-1 of Gypenoside L solution,respectively.Rats in the combination group were gavaged with 200 mg·kg-1·d-1 of Gypenoside L solution,and 2 mg·kg-1·d-1 of p38 MAPK agonist Anisomycin was in-jected into the tail vein.The rats in each group were gavaged with a volume of 2 mL per day for a total treatment period of 4 weeks.After the treatment,fundus photography was performed on the rats in each group,and retinal tissues were stained with hematoxylin and eosin(HE).Fasting blood glucose was measured using a Roche blood glucose meter,and se-rum insulin levels were measured using an ELISA kit.Retinal superoxide dismutase(SOD),catalase(CAT),glutathione peroxidase(GSH-Px),malondialdehyde(MDA),tumor necrosis factor-α(TNF-α),interleukin(IL)-1 β,and IL-6 levels were measured according to the instructions of the kit.Western blot was used to detect the protein levels of p38 MAPK,p-p38 MAPK,p65 nuclear factor-κB(NF-κB),p-p65 NF-κB,inducible nitric oxide synthase(iNOS),and cyclooxygenase(COX-2)in the retina.Results Compared with the model group,the blood glucose level was decreased,the serum insu-lin level was increased,the fundus neovascularization was reduced,the retinal damage was alleviated,the retinal SOD,CAT and GSH-Px levels were increased,the MDA level was decreased,the TNF-α,IL-1β and IL-6 levels were decreased,and the p-p38 MAPK,p-p65 NF-κB,iNOS and COX-2 protein levels were decreased in the low,medium and high dose group(all P＜0.05).Compared with the high dose group,the blood glucose level in the combination group was increased,the serum insulin level was decreased,the fundus neovascularization increased,the retinal damage was aggravated,the ret-inal SOD,CAT and GSH-Px levels were decreased,the MDA level was increased,the TNF-α,IL-1[3 and IL-6 levels were in-creased,and the p-p38 MAPK,p-p65NF-κB,iNOS and COX-2 protein levels were increased(all P＜0.05).Conclusion This study shows that Gypenoside L can reduce inflammation and oxidative stress by blocking the p38 MAPK signaling path-way,thereby playing a role in the treatment of DR.