Suppression of VEGF and STAT3 by Lipoic acid in Experimental Diabetic Rat Retina

ABSTRACT

PURPOSE: We evaluated whether lipoic acid as antioxidant could inhibit expression of VEGF and STAT3 in experimental diabetic rat retina. METHODS: Diabetes was induced chemically by injection of streptozotocin in 12 rats of 18 Sprague-Dawley rats. After induction of diabetes, lipoic acid was injected into the peritonium in 6 rats. So all rats were divided into 3 groups, normal group (n=6), diabetes mellitus (DM) group (n=6), lipoic acid treated group (n=6). The ocular tissue of the rats were collected on 8 weeks after diabetes induction. Difference of VEGF and STAT3 expression was investigated by immunohistochemistry, RT-PCR, western blot. The change of VEGF and STAT3 in lipoic acid treated group were evaluated in these experimental model. RESULTS: The VEGF and STAT3 expression was elevated in diabetic rat retina. The active form STAT3, phosphorylated STAT3 was also elevated. The VEGF and STAT3 expression in lipoic acid treated group was lower than DM group. CONCLUSIONS: The lipoic acid could inhibit the VEGF and STAT3 expression in diabetic rat retina.