Hyperhomocysteinemia-Induced Oxidative Stress Aggravates Renal Damage in Hypertensive Rats

BACKGROUND Hyperhomocysteinemia (HHcy) plays a synergistic role with hypertension in vascular injury; however, the relationship between HHcy and hypertension in renal injury remains unclear. Here, we sought to evaluate the relationship between HHcy and hypertension in the context of renal injury and to elucidate the mechanism of action underlying this relationship. METHODS Wistar Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) were randomized into WKY, WKY + HHcy, SHR, and SHR + HHcy groups. Blood pressure, plasma homocysteine, serum malondialdehyde (MDA), serum superoxide dismutase (SOD), urinary albumin creatinine ratio (UACR), and glomerular filtration rate (GFR) were measured. Renal histopathology and expression levels of NOX2, NOX4, and nephrin in the kidneys were examined. RESULTS The WKY + HHcy and SHR groups exhibited lower serum SOD and GFR levels, relative to the WKY group, along with higher levels of both serum MDA and UACR. Higher mRNA and protein expression levels of NOX2 and NOX4, along with lower expression levels of nephrin, were observed in the kidneys of WKY + HHcy and SHR rats, relative to WKY controls, respectively. Similar effects were observed in the SHR + HHcy group, relative to the SHR group and WKY + HHcy group, respectively. Periodic acid-Schiff staining showed an increase in the glomerular extracellular matrix in the WKY + HHcy and SHR + HHcy groups compared with their respective controls. CONCLUSIONS HHcy appears to synergistically increase hypertensive renal damage by enhancing oxidative stress.