ABSTRACT
<p><b>OBJECTIVE</b>To clarify the impact of increased heme oxygenase-1 (HO-1) expression on cardiac function of diabetic rats with myocardial infarction and its mechanism.</p><p><b>METHODS</b>Sixty adult male Wistar rats were randomly divided into five groups (n = 12): sham operation group (sham), diabetes + sham operation group (DM + sham), diabetes + MI group (DM + MI) , diabetes + myocardial infarction + cobalt original porphyrin (CoPP) group (DM + MI + CoPP), diabetes + myocardial infarction + CoPP+ tin porphyrin (SnMP) group (DM + MI + CoPP + SnMP). CoPP 4.5 mg/kg or SnMP 15 mg/kg were administered at the day next to MI operation, for six weeks, once a week. At the 28th week post operation, the echocardiography, left heart via the carotid artery indoor intubation were used to observe the long-term influence of HO-1 inducer (cobalt protoporphyrin, CoPP) and activity of HO inhibitor (tin porphyrin, SnMP) on the indices of left ventricular remodeling and cardiac function after the intervention. Blood glucose (GLU), total cholesterol (TC), C-reactive protein (CRP), serum creatinine (Cr), aminotransferase (ALT) and other indicators were measured. ELISA was used to test interleukin-6 (IL-6), tumor necrosis factor (TNF), nitric oxide (NO), prostacyclin (PGI2), adiponectin, and ultra sensitive CRP (HsCRP) level.</p><p><b>RESULTS</b>HO-1 inducer, CoPP, could ameliorate ± dp/dtmax, left ventricular ejection fraction and left ventricular shortening fraction in diabetic myocardial infarction rats. It could also decrease left ventricular end-diastolic diameter. The serum bilirubin, NO and PGI2 levels, myocardial phosphorylated endothelial nitric oxide synthasee(peNOS), phosphorylated activated protein kinase (pAkt), phosphorylated adenosine monophosphate-activated protein kinase (pAMPK) expression were also significantly elevated, and the serum hs-CRP and TNF levels were significantly inhibited. Compared to inducer group, cardiac function were worse in the inhibitor group.</p><p><b>CONCLUSION</b>Upregulated HO-1 level can improve the endothelial function, inhibite of the inflammatory response and enhance the antioxidant substances in serum bilirubin via peNOS-pAMPK pathway, which effectively inhibit ventricular remodeling and improve the long-term cardiac function after infarction in diabetic rats.</p>
Subject(s)
Animals , Male , Rats , Antioxidants , Metabolism , Bilirubin , Blood , Diabetes Mellitus, Experimental , Heme Oxygenase (Decyclizing) , Metabolism , Myocardial Infarction , Myocardium , Rats, Wistar , Signal Transduction , Up-Regulation , Ventricular Function, Left , Ventricular RemodelingABSTRACT
Ischemia/reperfusion (I/R) injury is the main cause of primary graft dysfunction of liver allografts. Cobalt-protoporphyrin (CoPP)-dependent induction of heme oxygenase (HO)-1 has been shown to protect the liver from I/R injury. This study analyzes the apoptotic mechanisms of HO-1-mediated cytoprotection in mouse liver exposed to I/R injury. HO-1 induction was achieved by the administration of CoPP (1.5 mg/kg body weight i.p.). Mice were studied in in vivo model of hepatic segmental (70 %) ischemia for 60 min and reperfusion injury. Mice were randomly allocated to four main experimental groups (n = 10 each): (1) A control group undergoing sham operation. (2) Similar to group 1 but with the administration of CoPP 72 h before the operation. (3) Mice undergoing in vivo hepatic I/R. (4) Similar to group 3 but with the administration of CoPP 72 h before ischemia induction. When compared with the I/R mice group, in the I/R+CoPP mice group, the increased hepatic expression of HO-1 was associated with a significant reduction in liver enzyme levels, fewer apoptotic hepatocytes cells were identified by morphological criteria and by immunohistochemistry for caspase-3, there was a decreased mean number of proliferating cells (positively stained for Ki67), and a reduced hepatic expression of: C/EBP homologous protein (an index of endoplasmic reticulum stress), the NF-κB's regulated genes (CIAP2, MCP-1 and IL-6), and increased hepatic expression of IκBa (the inhibitory protein of NF-κB). HO-1 over-expression plays a pivotal role in reducing the hepatic apoptotic IR injury. HO-1 may serve as a potential target for therapeutic intervention in hepatic I/R injury during liver transplantation.
