Forskolin attenuates retinal inflammation in diabetic mice

The present study aimed to investigate the effect of forskolin on retinal inflammation under diabetic conditions. C57BL/6 mice were randomly divided into normal control, diabetic control and forskolin treatment groups. The diabetic model was established by intraperitoneal injection of streptozotocin. The forskolin treatment group received intragastrical administration of forskolin for 12 weeks, the other two groups received an equal amount of PBS. At 21 weeks following diabetic induction, an immunoblotting test was conducted to investigate the expression of two inflammatory factors: Intercellular adhesion molecule-1 (ICAM-1) and tumor necrosis factor-α (TNF-α). Glucose concentration was additionally calculated. A leukostasis assay was utilized to compare microvasculature pathological alterations. It was demonstrated that retinal glucose concentration of diabetic control and forskolin treatment were both increased compared with normal control, however the forskolin treatment group was only ~68.06% of the diabetic control due to downregulated glucose transporter 1 expression. The expression of ICAM-1 and TNF-α were upregulated in the forskolin treatment and diabetic control groups compared with the normal control, however these two inflammatory factor expression levels in the forskolin treatment group were ~68.75 and 75.37% of diabetic control. It was additionally observed that there were less adherent leukocytes in retinal microvasculature in the forskolin treatment group compared with diabetic control. All the differences observed were significant. Overall, by means of limiting glucose transport into the retina via forskolin, the retinal environment with lower glucose concentration alleviates the inflammatory response under diabetic conditions.