The Evaluation of Estrogen and Tacrolimus in an Experimental Sciatic Nerve Injury Model Following Bipolar Electrocautery in an Animal Model

Introduction: Iatrogenic peripheral nerve injuries (PNIs) cause neurogenic deficits because of the limited regeneration potential of nerves and scar formation. This study evaluates the effects of tacrolimus and estrogen on sciatic nerve healing following its lesion by bipolar electrocautery in rats. Materials & Methods: Twenty-five mature female Wistar rats were included in this study. The rats were kept under the same photoperiod ۱۲:۱۲ for one week. The rats were divided into five groups as follows: Sham, DW (distilled water), Tacrolimus (Tac), Estrogen (Est), and Tacrolimus + Estrogen (Tac + Est). All rats were anesthetized, and the left sciatic nerve was cauterized by bipolar electrocautery, except for the rats in the sham group. Treatments were given for ۲۸ days after the injury; on day ۲۸, clinical, electrophysiological, and histopathological evaluations were carried out. The Rota-rod performance test, sciatic functional index (SFI), electromyography (EMG) latency, and toe-out angle (TOA) were carried out for evaluation of functional nerve recovery. Finally, the rats were humanly euthanized and samples of sciatic nerve tissue were submitted for histopathological evaluation on day ۲۸. Results: There was no statistically significant difference in SFI (P=۰.۲۴۹) among the groups. In the Rota rod tests, the Est group showed significantly greater motor function improvement compared with the DW (distilled water), Tac, and Est + Tac groups (P<۰.۰۱). Mean EMG latency in the DW group was significantly longer than in the sham (P<۰.۰۰۱), Tac (P=۰.۰۲۳) and Est + Tac (P=۰.۰۱۲) groups. Axonal swelling and inflammatory cell infiltration were less in the Tac, Est, and Est + Tac groups compared with the DW group (P<۰.۰۱). There was no significant difference among the Tac, Est, and Est + Tac groups in EMG latency. Therefore, tacrolimus and estrogen each showed a neuroprotective effect based on histopathological results. Motor function improvement and reduced inflammation were statistically significant in the Est and Tac groups, respectively. Conclusion: The findings of this investigation did not confirm a significant impact of the combination of estrogen plus tacrolimus compared with the estrogen and tacrolimus groups in functional recovery and inflammation.

کلیدواژه ها:

Electrocautery ، Estrogen ، rat ، Sciatic nerve ، Tacrolimus