Chronic angiotensin II (Ang II) increases renal oxidative stress in male spontanously hypertensive rats (SHR), but not in female SHR

Abstract

Male SHR are more sensitive to Ang II‐induced increases in blood pressure than females. Ang II‐induced oxidative stress contributes to hypertension in males; less is known regarding Ang II‐induced oxidative stress in females. We hypothesize female SHR have less Ang II‐induced oxidative stress compared to males. 13 week old control and Ang II infused (200 ng/kg/min, 14 day minipump) male and female SHR were studied (n=3–4). The renal cortex was isolated to measure O2·− levels via lucigenin. Males had higher O2·− levels than females (see figure, * indicates p<0.05). Ang II increased O2·− levels in males(+ indicates p<0.05) yet levels were similar in females and female + Ang. Renal cortical NADPH oxidase NOX4 and p22phox subunits, SOD and catalase protein expression were assessed. p22phox expression was comparable in males (4.0±0.2 rdu) and male + Ang (4.0±0.2 rdu), however, Ang II tended to decrease p22phox in females (female: 4.0±0.3 rdu; female + Ang: 3.4±0.1 rdu, p=0.07). Ang II decreased ECSOD expression in males (male: 24±1; male + Ang: 20±1 rdu, p<0.05), with no effect in females (female: 20±2; female + Ang: 22±1 rdu). NOX4, CuZn SOD, MnSOD, and catalase expression were comparable among groups. Ang II infusion increased oxidative stress in male, but not female SHR. We hypothesize that this is related to increased antioxidant potential and lowered NADPH oxidase activity in female SHR with Ang II infusion. Funded by NIH.