PROSTAGLANDIN E1 ALLEVIATES NEUROPATHIC PAIN AND NEURAL DYSFUNCTION FROM ENTRAPMENT NEUROPATHY ASSOCIATED WITH DIABETES MELLITUS

In this report, we present the results of investigation of the effects of prostaglandin E1 (PGE1) on entrapment neuropathy using a diabetic rat. A total of 60 male Sprague-Dawley rats were used in the study. The model of tibial nerve entrapment neuropathy associated with dia-betes mellitus was created by streptozotocin-induced diabetic rats reared in cages with wire grid flooring. Rats were assigned to four groups: nondiabetic (n5 15), untreated diabetic (n5 15), diabetic treated with 30 lg/kg PGE1 (n5 15), and diabetic treated with 100 lg/ kg PGE1 (n515). Pain tests and electrophysiological tests were performed at 0, 2, and 4 weeks, and assessments of gait, histology, and mRNA expression levels were performed at 4 weeks after initiating the PGE1 administration. In the 30 and 100 lg groups, the mechanical withdrawal thresholds measured by pain tests at 4 weeks (36.2616.4 g and 31.76 15.3 g, respectively) and the motor conduction veloc-ity (24.060.2 m/s and 24.46 0.3 m/s, respectively) were significantly higher than the untreated diabetic group (all P<0.05) and lower than the nondiabetic group (all P<0.001). In the gait analysis, the mean intensities in the 30 and 100 lg group (128.06 20.1 a.u. and 109.06 27.8 a.u., respectively) were significantly higher than the untreated diabetic (P<0.01) and were not significantly different from the nondiabetic group (P5 0.81). Fiber density (P5 0.46) and fiber diameter (P5 0.15) did not show any significant differences. PGE1 signifi-cantly decreased nerve growth factor (NGF) mRNA and increased vascular endothelial growth factor (VEGF) mRNA in the tibial nerve (both P<0.01). In conclusion, neurological deteriorations of diabetic rats were alleviated with PGE1, which is associated with inhibition of NGF and enhancement of VEGF at the entrapment site. VC 2014 Wiley Periodicals, Inc. Microsurgery 00:000–000, 2014. Chronic compression or strain on a nerve from pro