Inducible nitric-oxide synthase is an important contributor to prolonged protective effects of ischemic preconditioning in the mouse kidney.
Ischemic preconditioning renders the mouse kidney resistant to subsequent ischemia. Understanding the mechanisms responsible for ischemic preconditioning is important for formulating therapeutic strategies aimed at mimicking protective mechanisms. We report that the resistance afforded by 30 min of bilateral kidney ischemia persists for 12 weeks after preconditioning. The protection is reflected by improved postischemic renal function, reduced leukocyte infiltration, reduced postischemic disruption of the actin cytoskeleton, and reduced postischemic expression of kidney injury molecule-1 (Kim-1). The protection is observed in both BALB/c and C57BL/6J strains of mice. Thirty minutes of prior ischemia increases the expression of inducible nitric-oxide synthase (iNOS) and endothelial NOS (eNOS) and the expression of heat shock protein (HSP)-25 and is associated with increased interstitial expression of alpha-smooth muscle actin (alpha-SMA), an indication of long term postischemic sequelae. Treatment with Nomega-nitro-l-arginine (l-NNA), an inhibitor of NO synthesis, increases kidney susceptibility to ischemia. Gene deletion of iNOS increases kidney susceptibility to ischemia, whereas gene deletion of eNOS has no effect. Pharmacological inhibition of NOS by l-NNA or l-N6-(1-iminoethyl) lysine (l-NIL, a specific inhibitor of iNOS) mitigates the kidney protection afforded by 30 min of ischemic preconditioning. Fifteen minutes of prior ischemic preconditioning, which does not result in the disruption of the actin cytoskeleton, impairment of renal function, increased interstitial alpha-SMA, or increased iNOS or eNOS expression, but does increase HSP-25 expression, partially protects the kidney from ischemia on day 8 via a mechanism that is not abolished by l-NIL treatment. Thus, iNOS is responsible for a significant component of the long term protection afforded the kidney by ischemic preconditioning, which results in persistent renal interstitial disease, but does not explain the preconditioning seen with shorter periods of ischemia.
Park
Kwon Moo
KM
Renal Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
Byun
Ji-Yeon
JY
Kramers
Cornelis
C
Kim
Jee In
JI
Huang
Paul L
PL
Bonventre
Joseph V
JV
D000199:Actins / Q000378:metabolism; D000818:Animals; D001120:Arginine / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006360:Heat-Shock Proteins; D019194:Ischemic Preconditioning; D007668:Kidney / Q000098:blood supply* / Q000187:drug effects / Q000201:enzymology* / Q000293:injuries; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D019335:Nitroarginine / Q000494:pharmacology; D015427:Reperfusion Injury / Q000188:drug therapy / Q000201:enzymology / Q000517:prevention & control
D000199:Actins; D004791:Enzyme Inhibitors; D006360:Heat-Shock Proteins; C486113:Hsbp1 protein, mouse; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D019335:Nitroarginine; D001120:Arginine; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496317:Nos2 protein, mouse; C496315:Nos3 protein, mouse