The protective role of estrogen and its receptors in gentamicin-induced acute kidney injury in rats

Aim: Investigating the impact of 17 beta-Estradiol/estrogen receptors in gentamicin-induced nephrotoxicity. Main methods: Three weeks post-ovariectomy or sham surgery for the Wistar albino female rats, thirty sham rats were randomly grouped (n = 6), received either vehicle or gentamicin; the estrogen receptors down regulator (fulvestrant); gentamicin plus fulvestrant; gentamicin plus the phytoestrogen (genistein). Forty-eight ovariectomized rats were randomly grouped (n = 6), treated with either vehicle or gentamicin; fulvestrant; gentamicin plus fulvestrant; genistein; gentamicin plus genistein; estradiol benzoate; gentamicin plus estradiol benzoate. Just post-treatment termination, the traditional kidney injury biomarkers (serum creatinine and blood urea nitrogen) and novel biomarkers (serum Kidney injury molecule -1, cystatin C, lactate dehydrogenase and, gamma-glutamyl transferase) were determined. Bovine serum albumin labeled with fluorescence isothiocyanate assessed megalin expression/endocytic functionality in the proximal tubules epithelial cells (PTECs). The immunohistochemical investigation for the same-sectioned slides of PTECs assessed the correlation between estrogen receptors a and megalin receptors expression. Histopathological examination of PTECs and subjective scoring system graded the damage markers. Key findings: Estrogen receptor a expression was markedly dimensioned post-ovariectomy, co-localized and inversely correlated to megalin expression. Serum levels of the novel biomarkers were directly proportional to megalin expression in the PTECs and inversely correlated with estrogen receptor a expression. The injury was exaggerated in ovariectomized and intact rats received fulvestrant. Supplementation with estrogen or genistein ameliorated this injury. Significance: Estrogen/estrogen receptors have a protective impact on gentamicin-induced acute kidney injury. Estrogen receptors antagonist exacerbate the injury, and oppositely, estrogens or phytoestrogens improve it.