Sex Difference in Autoregulatory Responses of Juxtamedullary Afferent Arterioles Following Ischemia‐Reperfusion in Rats

• Published in: The FASEB journal 2022-05, Vol.36 (S1), p.n/a
• Main Authors: Guan, Zhengrong, Feng, Wenguang, Meera, Samia, Moore, Marina
• Format: Article
• Language: English
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fasebj.2022.36.S1.R4130

Renal ischemia‐reperfusion (IR) is a major cause of acute kidney injury (AKI). Renal autoregulation protects the kidney from ischemia at low arterial pressure and hyperperfusion at high arterial pressure. Female rats are more protected against AKI than male rats. We reported that IR impaired autoregulatory behavior of afferent arterioles (AA) in male rats 24 hours and 1‐week post‐IR. We hypothesize that AA autoregulatory control in IR‐induced AKI (IR‐AKI) is better preserved in female rats compared to males. IR was induced in female rats by bilateral renal arterial clamping for 60 minutes followed by reperfusion for 24 hours or 1 week. Autoregulatory responses were assessed using the in vitro blood‐perfused juxtamedullary nephron preparation during step increases in perfusion pressure (PP) from 65 to 170 mmHg at 15 mmHg intervals in sham‐operated and IR rats 24 hours and 1‐week post‐IR. AA from sham rats exhibited pressure‐dependent vasoreactivity. Baseline AA diameter averaged 12.1±1.4 µm in shams (n=3) 24 hours post‐surgery. Diameter increased to 112±2% of baseline when PP decreased from 100 to 65 mmHg and decreased to 70±6% of baseline when PP increased to 170 mmHg (P0.05) of baseline, indicating impaired autoregulation. Shams 1 week post‐IR (n=3) exhibited autoregulatory responses similar to 24‐hour shams. Intriguingly, autoregulatory responses normalized within 1 week in female IR rats (n=3) though these rats still maintained increased urine output over 1 week (P