ABSTRACT
ABSTRACT:Objective To explore the protective effect of the antioxidant N‐acetylcysteine (NAC) on the retinal nerve tissue of early diabetic rats .Methods We randomly divided 60 healthy adult Sprague‐Dawley (SD) rats weighing between 180 g and 220 g into 2 groups:normal control (CON , n=20) and diabetic (DM , n=40) .By intraperitoneal injection of streptozotocin (60 mg/kg) ,the model of diabetic rats was established .The rats were considered diabetic only when they had hyperglycemia (set at ≥16 .7 mmol/L) (32) .The CON group was injected with the same amount of citric acid and sodium citrate buffer solution .After successful model establishment ,the diabetic rats were randomly divided into 1‐month diabetes group and 2‐month diabetes group ,with 16 rats in each group .The left eye of each experimental diabetic rat was set for diabetes control group (D) while the right eye was set as NAC treatment group (NAC) .At 2 weeks of diabetes ,4μL (1 .6μg/μL) of NAC was injected into the vitreous chamber of NAC group and 4μL (0 .01 mmol/L) of PBS was injected into the vitreous chamber of the other diabetic rats .The thickness changes of outer nuclear layer retina was observed by HE ,ultrastructural changes of retinal ganglion cells were observed under the transmission electron microscope ,and the number of retinal ganglion cells was detected by immunofluorescence method .Results At different time points ,retina outer nuclear layer in NAC group was thicker than in D group (P0 .05) .Under the transmission electron microscope ,NAC group had more retinal ganglion cell organelles ,higher electron density of the cytoplasm ,and milder mitochondria swelling than D group .The NAC group did not differ from CON group in the ultrastructure of retinal ganglion cells . NAC group had an increased number of retinal ganglion cells at different time points compared with the D group (P 0 .05) .Conclusion The antioxidant N‐acetylcysteine has a protective effect on the retinal nerve tissue of early diabetic rats .