Glutathione peroxidase 4 prevents 12/15 LOX induced renal oxidative cell death and improves renal post Ischemic recovery in Male Spontaneous Hypertensive Rats (SHR)

Abstract

Acute kidney injury (AKI) due to ischemia‐reperfusion (IR) is a serious and frequent complication in hospital setting with high mortality rates. The mechanisms mediating renal IR injury leading to increased risk of later developing cardiovascular and renal diseases in either sex remain poorly understood. Glutathione peroxidase 4 (GPx4) is a negative regulator of 12/15 lipoxygenase (12/15 LOX) and any alteration in 12/15 LOX and GPx4 activity has been reported to contribute to the progression of kidney diseases. The goal of the current study was to test the hypothesis that an imbalance of 12/15 LOX/GPx4 activity in males leads to impaired recovery following IR compared to females. 13‐week‐old male and female SHR were subjected to sham or 30‐minute warm bilateral IR (n=6/group). Additional male SHR were randomized to receive vehicle or the GPx4 activity mimic ebselen (10 mg/kg i.p.; n=5/group) 1 hr prior to sham/IR, 1 day and 3‐day post IR. Blood and urine were collected from all rats 1 and 7 days after IR; kidneys were harvested 7 days post‐IR for biochemical, histological, and Western blot analysis. IR increased plasma creatinine (Pcr) and blood urea nitrogen (BUN) in both male and female SHR compared to respective sham controls at 24 hrs (PIR =0.0001; Psex*IR=0.2). At 7 days post‐IR, Pcr and BUN remained elevated in male SHR but returned to baseline levels in females (Pcr: PIR =0.03; Psex*IR=0.04; BUN: PIR <0.05; Psex*IR=0.05). Histological examination of kidneys 7 days post‐IR showed greater tubular damage (PIR=0.0003, Psex*IR=0.0019) and renal cell death (PIR=0.001; Psex*IR=0.001) in male vs. female SHR. Delayed recovery of renal function in male SHR was associated with activation of renal 12/15 LOX (PIR<0.05; Psex*IR=0.008), reduced renal GPx4 protein expression (PIR=0.05; Psex*IR<0.001), activity (PIR=0.01; Psex*IR=0.0016), and intracellular glutathione (GSH; PIR=0.01; Psex*IR=0.003), and increased lipid peroxidation (PIR=0.008; Psex*IR=0.018) compared to females. Pre‐treatment of male SHR with ebselen significantly reduced 12/15 LOX induced lipid peroxidation (PIR*TxT =0.02), prevented IR‐induced renal cell death (PIR*TxT=0.04) and tubular damage (PIR*TxT=0.02) and improved renal function (Pcr: PIR*TxT =0.027; BUN: PIR*TxT =0.022) compared to vehicle‐treated IR males 7 days post‐IR. In conclusion, our data demonstrate that increased GPx4 activity enhanced renal recovery post‐IR via inhibiting 12/15 LOX induced oxidative renal cell death in male SHR.