Prostaglandin E1 Protects Peripheral Nerve In Diabetic Rats Through Preventing Nourishing Vascular Permeability Changes

Objective: This study is to investigate the effects of prostaglandin E1 on microvascular permeability and the expression of VEGF as well as structural and functional changes of peripheral nerve in diabetic rats.Methods: Diabetic model was established in fifty-six Sprague Dawley rats by an intraperitoneal injection of streptozotocin at 65 mg/kg,eight rats dead in the process of modeling.Six rats were randomly selected as normal control, and received intraperitoneal injections of citrate buffer only. Four weeks later, the surviving rats that were confirmed with STZ-induced diabetes mellitus were randomly divided into two groups and intraperitoneally received, once daily, prostaglandin E1 injection at 1.6μg/kg in normal saline, or the same volume of normal saline(diabetic control), respectively. The tailflick threshold temperature and motor nerve conduction velocity(NCV) were tested. The levels of VEGF in serum and sciatic nerve were measured by ELISA and immunohistochemical analysis, respectively. The water content of the sciatic nerve was determined for the evaluation of vascular permeability. Histological and ultrastructure alterations were also examined.Results: Diabetic rats in the control group exhibited a significant increase in tailflick threshold temperature, water content of the sciatic nerve, serum VEGF level and VEGF level in sciatic nerve, and a decrease in sciatic NCV compared with normal rats(P <0.01). Treatment with prostaglandin E1 resulted in similar changes but at a slower rate than those without treatment. Diabetic control rats also showed histological and ultrastructure abnormalities of sciatic nerve, including myelin sheath swelling, decompaction and foam-like changes, and disorderly arranged microfilaments and microtubules in axons; whereas prostaglandin E1 partially protect sciatic nerve with less severe lesions. In T group of rats,sciatic nerve conduction velocity and the corresponding level of serum VEGF show negative correlation;Water content of sciatic nerve and the corresponding level of serum VEGF show positive correlation;sciatic nerve conduction velocity and the corresponding IOD value of immunohistochemistry show negative correlation; Water content of sciatic nerve and the corresponding IOD value of immunohistochemistry show positive correlation.Conclusion: Prostaglandin E1 could protect the peripheral nerve by improving the function of sciatic nerve, reducing the level of VEGF and the vascular permeability of peripheral nerve.