L-NIL prevents the ischemia and reperfusion injury involving TRL4, GST, clusterin and NFAT5 in mice.

Upon renal ischemia-reperfusion (IR) injury, recruitment of neutrophils during the inflammatory process promotes local generation of oxygen and nitrogen reactive species which, in turn, are likely to exacerbate tissue damage. The mechanism by which iNOS is involved in IR has not been completely elucidated. In this work, the selective iNOS inhibitor L-N6 -(1-iminoethyl)lysine (L-NIL) and the NOS substrate L-Arginine (L-Arg), were employed to understand the role of NOS activity on the expression of particular target genes and the oxidative stress elicited after a 30 min of bilateral renal ischemia, followed by 48h reperfusion in BALB/c mice. The main findings of the present study were that pharmacological inhibition of iNOS with L-NIL during an IR challenge of mice kidney decreased renal injury, prevented tissue loss of integrity, and improved renal function. Several novel findings regarding the molecular mechanism by which iNOS inhibition led to these protective effects: i) a prevention the IR-related increase in expression of TLR4, and its downstream target, IL1b; ii) reduced oxidative stress following the IR challenge; noteworthy, this study shows the first evidence of GST inactivation following kidney IR, a phenomenon fully prevented by iNOS inhibition; iii) increased expression of clusterin, a survival autophagy component; and iv) increased expression of NFAT5 and its target gene AQP-1. In conclusion, prevention of renal damage following IR by the pharmacological inhibition of iNOS with L-NIL was associated with the inactivation of proinflammatory pathway triggered by TRL4, oxidative stress, renoprotection (autophagy inactivation) and NFAT5 signaling pathway.