Silybin reduces obliterated retinal capillaries in experimental diabetic retinopathy in rats.

Silybin has been previously reported to possess anti-inflammatory properties, raising the possibility that it may reduce vascular damage in diabetic retinopathy. Present study was designed to investigate this potential effect of silybin and its underlying mechanisms in experimental diabetic retinopathy. Diabetes was induced with streptozotocin (STZ) plus high-fat diet in Sprague-Dawley rats, and silybin was administrated for 22 weeks after the induction of diabetes. Histochemical and immunofluorescence techniques were used to assess the obliterated retinal capillaries, leukostasis, and level of retinal intercellular adhesion molecule-1 (ICAM-1). Western blot was performed to quantitate the expression of retinal ICAM-1. Results showed that silybin treatment significantly prevented the development of obliterated retinal capillaries in diabetes, compared with vehicle treatment. In addition, leukostasis and level of the retinal ICAM-1 were found to decrease considerably in silybin-treated diabetic groups. In conclusion, these results indicate that silybin reduces obliterated retinal capillaries in experimental diabetes, and the recovered retinal vascular leukostasis and level of ICAM-1 at least partly contributes to the preventive effect of silybin.