Mehdi Nematbakhsh’s research while affiliated with Isfahan University of Medical Sciences and other places

Background: Renal hemodynamic is influenced by both gender difference and age. Also, the Mas receptor (MasR) as one of the depressor components of the renin-angiotensin system which has more expression in females could postpone some dysfunctions associated with age, although the association between MasR and age in renal vascular responses to angiotensin II (Ang II) in male and female rats was well undefined. Therefore, the current study examined the effects of age and sex on systemic and renal vascular responses to graded doses of Ang II in Wistar rats with or without MasR antagonists (A779). Materials and methods: Anesthetized Wistar male and female rats with two age ranges of 8-12 and 24-28 weeks were exposed to cannulate venous and arterial vessels. After stability, mean arterial pressure (MAP), renal perfusion pressure (RPP), renal vascular resistance (RVR), and renal blood flow (RBF) were measured in response to the infusion of Ang II with or without A779. Results: There were no significant differences in the base values of MAP, RPP, RBF, and RVR between the two genders in both the age ranges of 8-12 and 24-28 weeks. In addition, no significant gender difference was observed in the age ranges of the above mentioned parameters among the groups receiving vehicle or A779. Also, the infusion of vehicle or A779 could not significantly change the base values. On the other hand, the responses of RBF and RVR to Ang II revealed gender differences among 8-12-week groups (P < 0.05) but not in 24-28-week groups, while the blockade of MasR could not influence the responses in the age ranges. Conclusion: It was concluded that age could impress sex difference in RBF and RVR responses to Ang II infusion and that MasR alone could not participate in these responses. In other words, MasR is not active under normal and acutely elevated Ang II levels.

Background and purpose: Renal ischemia/reperfusion (IR) injury is a pathologic phenomenon that caused to increase risk of mortality. The main objective of this study was to investigate the effect of sodium hydrogen sulfide (NaHS) on renal IR injury in male and female rats. Experimental approach: Fifty-eight male and female rats were randomized into 4 groups of control, sham, IR, and IR + NaHS. The IR was performed by 45 min of ischemia by vessel clamping followed by 24 h reperfusion. The NaHS (100 µmol/kg) treatment was applied 10 min prior to IR. Finally, after 24 h of reperfusion, the measurements were performed. Findings/results: The serum levels of blood urea nitrogen, creatinine, tissue level of malondialdehyde, and kidney tissue damage score (KTDS) were increased by IR. Urine volume, creatinine, and urea clearances decreased by IR. NaHS administration improved some parameters in males but exacerbated KTDS and serum markers related to renal function. Conclusions and implications: Our data demonstrated that NaHS didn't protect female rats against renal IR injury. In males, it has null effects or just a few protective effects via antioxidant activity.

Renin angiotensin (RAS), kallikrein kinin (KKS), and sex hormonal systems demonstrate a complex contribution in kidney circulation. This study was designed to investigate the role of angiotensin 1-7 (Ang 1-7) receptor (MasR) and of bradykinin B2 receptor (B2R) in renal blood flow (RBF) response to Ang 1-7 infusion in ovariectomized estradiol treated rats. The ovariectomized rats received intramuscular vehicle (group 1, OV) or estradiol valerate (500 µg/Kg/week) (group 2, OVE) for two weeks. Then each group was divided into two subgroups subjected to receive B2R antagonist (HOE-140, subgroup A), or MasR antagonist (A779) plus HOE-140 (subgroup B). RBF and renal vascular resistance (RVR) responses to graded Ang 1-7 infusion were determined. In condition of B2R alone blocking, RBF response to Ang 1-7 in OVE group was significantly greater than that of OV group (P=0.05), however this response difference was failed by co-blockades of MasR and B2R. Estradiol could promote RBF response to graded Ang 1-7 infusion in the absence of B2R alone, however when both receptors (MasR and B2R) were blocked the role of estradiol was limited. © 2019 Tehran University of Medical Sciences. All rights reserved.