| Acute myocardial infarction (AMI) is the disease which severely menaces people's health. The key of preventing and curing myocardial ischemic necrosis is to revive the myocardium at risk, improve the tolerance of myocytes to ischemia,decrease the degree of injury.lt is reported that basic fibroblast growth factor (bFGF) , as a cardiopro-tective factor, play a role in the process of myocardial ischemia.bFGF, which widespreads in many kinds of tissues, is a kind of polypeptide growth factor. It is widely located in myocytes and extracellular matrix, When the myocardium suffers ischemia, the expression and production of regional bFGF increase. On one hand, the increased bFGF, as a mitogen, can promote neovasculization, enhance collateral flow, improve blood supply to myocardium at risk; On the other hand, it can reduce the production of oxide free radicals and calcium overload, slow down the depletion of energy reserve ofmyocytes,low down the degree of ischemia-reperfusion injury. So the cardioprotective effect is shown.Recently, lots of research were performed on the influence of bFGF on the myocardium suffering ischemia-reperfusion injury, but the mechanism of the cardioprotection of bFGF is yet not clear, especially whether K (ATP) channels play a role in it is not reported. The objectives of this experiment are to observe the effect of bFGF on the myocardial necrosis induced by isoproterenol in rats, and via the administration of glibenclamide, a specific antagonist of the K (ATP) channels, to examinate if the latter are involved in the cardioprotective effect of bFGF.Method: (1) 40 Wistar rats were randomly allocated into 5 groups: Control group isoproterenol group (ISO group ) bFGF protection group ( bFGF group) bFGF+glibenclamide group ( bFGF+Glib group ) and glibenclamide group ( Glib group ) ,each of which had 8. (2) The animals were handled as follow:Control group:2.5ml saline was injected intraperitoneally while 0.3ml saline through caudal vein, and two dose of mixed saline (each 1ml) , which contained 10% each of absolute ethanol and TweenSO in saline, was injected subcutaneously at 30min and 60min before canal vein injection; (2) ISO group: isoproterenol (ISO:80mg/kg) diluted with saline to 2.5ml was injected intraperitoneally while 0.3ml saline through caudal vein, the administration of the mixed saline was same as that of Control group;(3)bFGF group: the administration of ISO andthe mixed saline was same as that of ISO group,while the saline (0.3ml) which was injected through caudal vein contained 8ug of bFGF;(DbFGF+Glib group: the administration of bFGF and ISO was same as that of bFGF group, while the mixed saline (each 1ml) , which was injected at 30min and 60min before bFGF injection, contained 0.3mg/kg of glibenclamide each; Glib group: the administration of ISO and glibenclamide was the same as that of groups before, while the 0.3ml of saline injected through caudal vein was same as Control group. (3) All animals were anesthetized with 10% chloralhydrate (30mg/kg) intraperitoneally after 24h and blood was sampled from carotid artery. The activity of lactic dehydrogenase(LDH)in serum was detected with LDH kits; The hearts were isolated and cold saline was used to clean the cardiac chamber, Then parts of ventricular muscles were sampled and weighed to measure the contents of calcium and ATP; The myocardium in apex was sampled,stained with HE and examined with microscope,graded pathologically, and the substructure of myocardium was detected with electroscope. (4) Statistics: The data were processed with SPSS 10.0.Results : ( 1 ) The activity of LDH in serum in Control group ISO group bFGF group bFGF+Glib group and Glib group was (5780.75 + 498.55) U/L, (14686.00 + 613.23) U/L (7624.00 + 460.89) U/L, (11919.50 + 752.45) U/L and (14554.00 + 456.45) U/L respectively, The activity of LDH in ISO group was significantly higher than that in Control group (p < 0.05) and bFGF group (p <0.05 ) , and in bFGF+ Glib group, it was significantly higher than that of bFGF...
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