3-n-butylphthalide (NBP) reduces apoptosis and enhances vascular endothelial growth factor (VEGF) up-regulation in diabetic rats

Objective: The aim of this study was to investigate the protective effect of dl-3-n-butylphthalide (NBP) on chronic brain injury caused by diabetes. Methods: A group of diabetic Sprague-Dawley rats was orally treated with NBP for 6 weeks. In this study, we examined glial reactivity in hippocampus of streptozotocin (STZ)-induced diabetic rats by determining the expression of glial fibrillary acidic protein (GFAP) and CD11b. We also examined anti-apoptosis protein, vascular endothelial growth factor (VEGF) and key apoptosis enzyme, caspase-3, expression by immunohistochemistry. Results: We found that GFAP, CD11b, VEGF (685.1 +/- 35.5cells/mm(2) in diabetic rats versus 320.6 +/- 21.9 cells/mm(2) in control rats, p<0.05, n=5) and VEGF(+)-caspase-3(+) (393.4 +/- 24.2 cells/mm(2) versus 135.8 +/- 12.0 cells/mm(2) in control rats, p<0.05, n=5) immunostaining increased in the hippocampus of diabetic rats; However, treatment with NBP resulted in an obvious reduction of GFAP and CD11b-immunoreactive gliocytes in hippocampus. VEGF expression was up-regulated (837.2 +/- 20.1 cells/mm(2), n=5), while the caspase-3 expression was reduced (240.0 +/- 15.1 cells/mm(2), n=5) in the NBP-treated diabetes mellitus-NBP rats. Conclusion: These results suggest that diabetes causes increased glial reactivity, apoptosis and compensatory VEGF expression, and NBP may have a protective effect for diabetic brain damage through enhancing VEGF expression to inhibit caspase-3 mediated apoptosis.