The effects of co-administration of pregabalin and vitamin E on neuropathic pain induced by partial sciatic nerve ligation in male rats

This study was performed to evaluate the effect of pregabalin co-administration with vitamin E in Partial Sciatic Nerve Ligation (PSNL)-induced neuropathic pain in rats. Male Wistar rats were randomly allocated as control, sham, and PSNL groups (n = 8). PSNL was induced by tight ligation of the sciatic nerve with a copper wire. On day 14th, the PSNL and sham operated rats received either pregabalin (1, 3, and 30 mg/kg), vitamin E (100 and 200 mg/kg), or their combination intraperitoneally. An antinociceptive effect was evaluated as latency times and Maximum possible Effect Percent (%MPE) using tail-flick test. Locomotor activity was evaluated by open-field test before PSNL surgery and then twice at the 14th days (before and after drug injection). Ligated nerves were removed on the 28th days after surgery for histological examinations. The time course of latency times and %MPE showed significant decrease in PSNL but not in sham and control groups. Pregabalin (3 and 30 mg/kg) and vitamin E (100 and 200 mg/kg) caused significant increases in latency time in PSNL (but not sham) group compared to control group. Vitamin E 200 mg/kg increased significantly %MPE in PSNL group compared to sham group. In addition, the %MPE following combination treatment of pregabalin (30 mg/kg) and vitamin E (100 mg/kg) was significantly higher than both vitamin E and control group. Also combination of pregabalin with 100 mg/kg of vitamin E reversed Wallerian degeneration of sciatic nerve and the inflammatory responses to almost similar to sham group. Pregabalin and vitamin E did not affect locomotor activity. Our results showed antinociceptive effects of both vitamin E and pregabalin alone or in combination in PSNL rats and also neuroprotective properties without affecting locomotor activity.