Interaction of Sex Hormones and the Renin-Angiotensin System in Ovariectomized Rats Subjected to Ischemia-Reperfusion Induction.

BACKGROUNDS: Ischemia-reperfusion (IR) injuries occur in a variety of clinical conditions, which lead to kidney damage. Most of the tissue damages after IR are due to the activation of the renin-angiotensin system (RAS). Hence, in this study, the interaction of sex hormones and RAS in ovariectomized (OV) rats subjected to IR induction has been studied. MATERIALS AND METHODS: The animals were divided into different groups. Groups 1 (OV + E, OV rat + estradiol) and 2 (OV rat) each one consisted of three separate IR-induced subgroups treated with losartan, angiotensin 1-7 (Ang 1-7), and their combination, Group 3, as control and Group 4, as sham. Next, 72 h after IR, blood samples were collected, the right kidneys were homogenized, and left kidneys were fixed in 10% formalin. RESULTS: Findings show that serum blood urea nitrogen, creatinine, and kidney tissue damage score levels increased significantly with induction of IR (P < 0.05). Mean serum levels of these factors in OV + E groups are higher than those of the OV. The presence or absence of estradiol did not affect the levels of antioxidants in the different groups receiving Los, Ang 1-7, and their combination. Los, Ang 1-7, and their combination reduced serum and kidney malondialdehyde levels in both OV and OV + E groups. CONCLUSION: Estrogen not only fails to improve renal functioning but it can also exacerbate it. While the treatments used in this study, in the absence of estradiol, it had a better effect on kidney damages and improved its functions.