Role of endogenous nitric oxide in TNF-alpha and IL-1beta generation in hepatic ischemia-repefusion.
In the present study, we examined the role of nitric oxide (NO) in early-response cytokine production by using a rat model of hepatic ischemia-reperfusion (HI/R). The left and median lobes of the liver were subjected to 30 min of ischemia, followed by 4 h of reperfusion. Group I and II rats were sham-operated controls that received saline (vehicle) or N(W)-nitro-L-arginine methylester (L-NAME) (10 mg/kg, iv); group III and IV rats were subjected to HI/R and received vehicle or L-NAME (10 mg/kg, iv, 10 min before reperfusion), respectively. Administration of L-NAME to rats subjected to I/R resulted in a fourfold decrease in plasma NO levels, accompanied by a marked increase of plasma alanine aminotransferase (ALT) activity relative to group III. These changes in group IV were associated with elevation of superoxide generation in ischemic liver lobes by 2.1-fold and circulating leukocyte number by 1.42-fold, compared with group III. Normalized for expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) messenger ribonucleic acid (mRNA), expression of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) mRNA in ischemic liver of group IV was augmented by 207% and 175% compared with Group III. The expression of (iNOS) mRNA was also increased (223%) relative to group III. Moreover, in group IV, plasma TNF-alpha levels at 4 h of reperfusion and IL-1beta levels at 90 min and 4 h of reperfusion were significantly increased compared with group III. No statistically significant changes were observed between groups I and II in plasma ALT activity, plasma NO levels, circulating leukocyte counts, superoxide generation in the ischemic lobes of liver, and plasma TNF-a and IL-1beta concentrations. The observed enhancement of I/R injury by L-NAME is consistent with the hypothesis that endogenous NO down-regulates TNF-alpha and IL1beta generation, thereby decreasing HI/R injury.
Liu
P
P
Department of Cell Biology, University of Medicine and Dentistry of New Jersey, School of Osteopathic Medicine, Stratford 08084, USA.
Xu
B
B
Spokas
E
E
Lai
P S
PS
Wong
P Y
PY
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007375:Interleukin-1 / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D007511:Ischemia / Q000188:drug therapy / Q000378:metabolism*; D007958:Leukocyte Count; D008099:Liver / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009566:Nitrates / Q000097:blood; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D009573:Nitrites / Q000097:blood; D012333:RNA, Messenger; D051381:Rats; D011916:Rats, Inbred F344; D015427:Reperfusion Injury / Q000188:drug therapy / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*
D004791:Enzyme Inhibitors; D007375:Interleukin-1; D009566:Nitrates; D009573:Nitrites; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D013481:Superoxides; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D000410:Alanine Transaminase; D019331:NG-Nitroarginine Methyl Ester