Sodium nitroprusside decreased leukotriene C4 generation by inhibiting leukotriene C4 synthase expression and activity in hepatic ischemia-reperfusion injured rats.
The effects of NO on LTC4 generation during hepatic ischemia-reperfusion (I/R) are largely unclear. Sprague-Dawley rats were divided into control, I/R and sodium nitroprusside (SNP, 2.5, 5 and 10 microg/kg/min)+I/R groups. Liver was subjected to I/R injury, saline or SNP administered intravenously. The protein expressions of LTC4 synthesis enzymes including LTC4 synthase (LTC4S), microsomal glutathione-S-transferase (mGST)2 and mGST3 were detected with immunoblotting, the LTC4 synthesis enzymes' activities and LTC4 content were measured by RP-HPLC, the mRNA expressions of inducible nitric oxide synthase (iNOS) and endogenous nitric oxide synthase (eNOS) in liver were measured by RT-PCR. Tissue injuries were assessed by serum ALT and AST and histological changes. Serum NO(2)(-) and liver tissue GSH were also examined. Compared with I/R group, SNP markedly decreased LTC4 content, LTC4S protein and iNOS mRNA levels, and the LTC4 synthesis enzymes' activities (P<0.05), but significantly enhanced eNOS mRNA expression in liver (P<0.05). The decline in serum ALT, AST and NO(2)(-) levels (P<0.05) together with hepatic GSH elevation (P<0.05) in SNP+I/R groups were also observed. LTC4S expression in hepatocytes and sinusoidal endothelial cells in SNP+I/R groups was lower than that in I/R group. But no significant differences in the protein expressions of mGST3 and mGST2 existed between control, I/R and SNP+I/R groups (P>0.05). These results demonstrated that the decline in LTC4 production by SNP treatment during hepatic I/R could be partially resulted from SNP down-regulating the protein expression of LTC4S rather than mGST2 or mGST3 and its inhibiting the LTC4 synthesis enzymes' activities.
Yang
Shu-Long
SL
Institute of Pharmacology-Toxicology and Biochemical Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
Lou
Yi-Jia
YJ
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D004305:Dose-Response Relationship, Drug; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism*; D017997:Leukotriene C4 / Q000096:biosynthesis* / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D008107:Liver Diseases / Q000378:metabolism*; D008297:Male; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000188:drug therapy / Q000378:metabolism*; D013997:Time Factors
D020030:Nitric Oxide Donors; D012333:RNA, Messenger; D009599:Nitroprusside; D017997:Leukotriene C4; D005982:Glutathione Transferase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; C041116:leukotriene-C4 synthase