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

Vazir, Nima; Fattahian, Hamidreza; Jahandideh, Alireza; Mortazavi, Pejman

doi:10.22092/ari.2025.369924.3719

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

Articles in Press

Document Type : Original Articles

Authors

¹ Department of Veterinary Clinical Sciences, SR.C., Islamic Azad University, Tehran, Iran.

² Department of Veterinary Pathobiology, SR.C., Islamic Azad University, Tehran, Iran.

10.22092/ari.2025.369924.3719

Abstract

Iatrogenic peripheral nerve injuries (PNIs) cause neurogenic deficits because of limited regeneration potential of nerve and scar formation. This study evaluates effects of tacrolimus and estrogen on sciatic nerve healing following its lesion by bipolar electrocautery in rat. Twenty-five mature female Wistar rats were included into this study. The rats kept in same photoperiod twelve-twelve for one week. The rats divided into five groups, five in each group as: Sham, DW (distilled water), Tacrolimus (Tac), Estrogen (Est), and Tacrolimus + Estrogen (Tac + Est). All rats anesthetized and sciatic nerve of left sciatic nerve was cauterized by bipolar-electrocautery except of rats in sham group. Treatments were given for 28 days after the injury; on day 28 clinical, electrophysiological, and histopathological evaluations were carried out. 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 killed humanly and sample of sciatic nerve were submitted for histopathological studies on day 28. There did not find significant difference statistically in SFI (p = 0.249) among all groups. On rotarod tests, the Est group showed significant motor function improvement than the DW (distilled water), Tac, and Est + Tac groups (p < 0.01). Mean EMG latency in DW group was significantly longer than sham (p < 0.001), Tac (p = 0.023) and Est + Tac (p = 0.012) groups. Axonal swelling and inflammatory cell infiltration were less in the Tac and Est and Est + Tac groups to DW group (p < 0.01). There was no significant difference among Tac, Est, Est + Tac groups in EMG latency. Therefore, tacrolimus and estrogen solely showed neuroprotective role based on histopathological results. Motor function improvement and less inflammation were significant statistically in Est and Tac groups, respectively. The finding of this investigation did not confirm the significant impact of the combination of estrogen plus tacrolimus in comparison to estrogen group and tacrolimus group in functional recovery and inflammation.

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