Dexamethasone pretreatment reduces isoproterenol-induced myocardial injury and the expression of TNF-α

Objective To investigate potential protective effect of glucocorticoid receptor( GR) agonist dexamethasone on isoproterenol-induced myocardial injury and the possible mechanism. Methods The sixteen mice were randomly divided into control( CON) group( n = 4),ISO group( n = 4),Dexamethasone pretreatment( DEX-pre) group( n = 4) and Dexamethasone treatment( DEX) group( n = 4). The mice in CON group and ISO group were given the same amount of 0. 9% sodium chloride and DEX-pre group given dexamethasone( 1. 25 mg / kg) injection by intraperitoneal injection as a pretreatment before treatment 30 minutes. CON group was given the same amount of 0. 9% sodium chloride injection by intraperitoneal injection. ISO group,DEX-pre group and DEX group received 5 mg / kg isoproterenol hydrochloride with daily intraperitoneal injection and continuous 3 days. At the two and three days,dexamethasone( 1. 25 mg / kg) was given after ISO injected 30 minutes in DEX group. Observe the serum ASL,LDH,CK,and CK-MP. Myocardial tissue injury was assessed by HE staining. The expression of TNF-α on serum was detected by ELISA. Results1 Compared with control group,the levels of ASL,LDH and CK was significantly increased; the degree of myocardial injury were greatly deteriorated in ISO group( P 0. 01). The expression of TNF-α on serum was greatly increased( P 0. 05) in ISO group.The expression of TNF-α on serum was significantly reduced( P 0. 01) in DEX-pre group. 2 Compared with ISO group,the levels of ASL and CK was significantly reduced( P 0. 01) and the levels of LDH and CK-MP was reduced( P 0. 05). The degree of myocardial injury were greatly improved( P 0. 01) in DEX-pre group. The expression of TNF-α on serum was significantly reduced( P 0. 01) in DEX-pre group. 3 Compared with ISO group,the levels of ASL,LDH,CK,CK-MP and the degree of myocardial injury weren't significantly difference in DEX group( P 0. 05). The expression of TNF-α on serum was significantly increased( P 0. 01)in DEX group. Conclusion DEX pretreatment has protective effect against ISO-induced myocardial injury. The mechanism might be the changes of inflammatory cytokinesthe.