Does FK506 reduce the size of the watershed area after vascular injury of the sciatic nerve

Aim: FK506 (also known Tacrolimus, Prograf) is an immunosuppressant drug which is used to prevent rejection after organ transplantation. Although there are several studies on neuroprotective effect of FK506 on brain ischemia, few reports on effects of FK506 after peripheral nerve ischemia have been reported. In the present study, we examined the size of watershed area after stripping of the epineurial vessels and studied the effect of FK506 on reduction of the size of watershed area. Materials and Methods: Forty-eight adult female rats were used and randomly divided into four groups as control, sham, FK506-treated and vehicle-treated. In FK506-treated and vehicle-treated groups epineurial vessels around the sciatic nerve (vasa nervorum) were stripped. Additionally, FK506-treated group were received subcutaneous injection of 5 mg/kg FK506. Percent of watershed area (100 × total watershed areas / total nerve area) after stripping and FK506 treatment was calculated. Results: We found no significant difference in comparison of the total size of watershed areas in FK506 and vehicle-treated groups or even the percent of the watershed area in both groups. Conclusions: We think that this study will be helpful to understand neuroprotective effect of FK506 and will give an insight into sparing of the nerve fibers from vascular injuries of the peripheral nerve.