鼠尾草酸对青光眼大鼠视网膜的保护作用及其机制OA

Objective To explore the protective mechanism of carnosic acid(CA)on the retina of glaucomatous rats.Methods Ninety healthy male SPF-grade SD rats were randomly divided into 6 groups according to a random num-ber table,with 15 rats in each group:control group,model group,low-dose CA group(CA-L group),high-dose CA group(CA-H group),high-dose CA combined with recombinant receptor-interacting protein kinase 1(rRIP1)group(CA-H+rRIP1 group),and RIP 1 inhibitor Nec-1 group(Nec-1 group).Except for the control group,rats in all other groups were sub-jected to glaucoma model establishment using the right eye as the experimental eye.After successful model establishment,each group received the following treatment regimens once daily for three weeks:rats in the CA-L group received an intrap-eritoneal injection of 50 mg·kg-1 CA;rats in the CA-H group received an intraperitoneal injection of 100 mg·kg-1 CA;rats in the CA-H+rRIP1 group received an intraperitoneal injection of 100 mg·kg-1 CA along with a tail vein injection of 8 µg·kg-1 rRIP1;rats in the Nec-1 group received an intraperitoneal injection of 0.6 mg·kg-1 Nec-1;rats in the control and mod-el groups were administered an equal volume of normal saline via the same injection method.After the intervention period,the intraocular pressure of the right eye(experimental eye)in rats from each group was measured using a GT600 non-con-tact tonometer.Histological analysis was performed using hematoxylin-eosin(HE)staining;the apoptosis of retinal ganglion cell(RGC)was detected by the TUNEL method;the proportion of IBA1-positive cells was assessed via immunofluorescence staining;and the levels of tumor necrosis factor-α,interleukin-18,and interleukin-1β in retinal tissues of rats from each group were measured by an enzyme-linked immunosorbent assay(ELISA).Thiobarbituric acid was used to measure the ma-londialdehyde(MDA)content in retinal tissues,the hydroxylamine method was employed to detect the superoxide dis-mutase(SOD)activity,and the enzyme coupling method was utilized to measure the glutathione peroxidase(GSH-PX)ac-tivity.Western blot is applied to measure the expression levels of retinal apoptosis-related proteins.Results Compared to the model group,CA intervention significantly reduced intraocular pressure in glaucomatous rats,alleviated retinal his-topathological damage,increased retinal thickness and the number of RGCs,and decreased the RGC apoptosis.In addition,CA upregulated the expression of the microglial activation marker IBA1,lowered the levels of inflammatory factors such as tumor necrosis factor-α,interleukin-1β,and interleukin-18 in the retina,reduced the content of the oxidative product MDA,and enhanced the activity of the antioxidant enzymes such as SOD and GSH-PX.At the molecular level,CA downregulated the expression of the pro-apoptotic protein cleaved caspase-3 and key necroptosis pathway-related proteins including RIP1,RIP3,and phosphorylated mixed lineage kinase domain-like protein(p-MLKL)/MLKL,while upregulating the expression of the brain-derived neurotrophic factor.However,exogenous supplementation of rRIP1 partially reversed the aforementioned protective effects of CA.Conclusion CA may alleviate retinal damage in glaucomatous rats by inhibiting the RIP1/RIP3/MLKL pathway and reducing retinal inflammatory response,oxidative stress,and RGC apoptosis.