The comparative effects of estrogen and tacrolimus on crushed sciatic nerve regeneration in male mice: functional and histopathological evaluation.

Some pharmacological agents can be effective for peripheral nerve injuries treatments. Present study was aimed to apply different agents and to compare the nerve regenerative effects following crushed sciatic nerve injuries. Twenty-four adult male mice were conducted in this study. Standard unilateral left side sciatic nerve crush was performed with 2.00 mm width mosquito hemostat forceps. The mice were randomly divided into four groups with the same numbers in each group which received subcutaneously, estrogen (group I), tacrolimus (group II), the combination of estrogen and tacrolimus (group III), and saline 0.90%. Functional recovery, histopathology, and immunohistochemistry (IHC) were performed on days 14 and 28. Walking track analysis on day 14 showed no significant difference between experimental groups, however, they showed significant difference compared to the control group. At the same time, experimental groups showed similar results of inflammatory cell infiltration, axonal edema, and count with significant differences compared to control group. At the end of the study, group I and III showed a significant difference in functional recovery between group II and control. After fourth week significant histopathological difference of axonal count was observed in group III. On day 28, only IHC assessment in group III showed more glial fibrillary acidic protein (GFAP) expression compared to the same group on day 14. This study revealed subcutaneous administration of combined estrogen and tacrolimus could be effective with acceptable results in nerve regeneration.