Protective Effects And Mechanism Of Astragaloside â…£ On Primary Cultured Cardiomyocytes Injured By Adriamycin In Newborn Rats

OBJECTIVE: To investigate protective effects and mechanism of astragalosides IV on primary cultured cardiomyocytes in newborn rats injured by adriamycin.METHODS: Adriamycin (ADR) was administered to establish the injury model of primary cultured cardiomyocytes in newborn rats. Primary cultured cardiomyocytes were randomly divided into four groups: control group;ADR group (2 mg/L): cardiomyocytes were incubated with ADR (2 mg/L) for 3 h;AST group (20 mg/L): cardiomyocytes were incubated with AST (20 mg/L) for 4 h;AST+ADR group: ADR (2 mg/L) was administered 1 h after treatment with AST (20 mg/L) and incubated for another 3 h. The activity of lactate dehydrogenase (LDH) in the culture medium was detected. The activity of sarcoplasmic reticulum Ca²⁺-ATPases (SERCA) was also evaluated by determination of Ca²⁺-dependent p-nitrophenyl phosphatase (pNPPase). The mitochondria were labeled by Rhodamine123 fluorescence probe and the fluorescent intensity produced by Rh123 was measured, which reflects changes of mitochondrial membrane potential (MMP, ΔΨm). Western blot was performed to exam expression of Bcl-2/Bax in cardiomyocytes respectively.RESULTS:1. Activity of LDH: Compared with control group, the activity of LDH wasincreased significantly in ADR group (230.2±15.8 vs 107.8±14.0 U/L, P<0.01). Compared with ADR group, the activity of LDH was decreased in AST+ADR group significantly (130.0±25.9 vs 230.2±15.8 U/L, P<0.01). There was no difference in the activity of LDH between AST group, AST+ADR group and control group.2. Activity of SERCA: Compared with control group, the activity of SERCAwas decreased significantly in ADR group (4.9±1.5 vs 8.9±2.3 umol-min"1-g"1pro, P<0.0l). Compared with ADR group, the activity of SERCA was increased in AST+ADR group significantly (7.3±1.9 vs 4.9±1.5 umol-min"1-g"'pro, P<0.0\). There was no difference in the activity of SERCA between AST group, AST+ADR group and control group.3. ATm: Compared with control group, ATm was decreased significantly in ADR group (1.4xl05±0.3xl05 vs 3.0xl05±0.4xl05, PO.01). Compared with ADR group, ATm was increased in AST+ADR group significantly (2.6xl05±0.5xl05 vs 1.4xlO5±O.3xio5, PO.01). There was no difference in the fluorescent intensity between AST group, AST+ADR group and control group.4. Expression of Bcl-2/Bax: The expression of Bax in ADR group was markedly higher than that of control group (108.3 + 8.6 vs 91.3 + 6.3, P<0.05). Compared with control group, the expression of Bcl-2 and the ratio of Bcl-2/Bax in ADR group decreased significantly (82.7 + 8.7 vs 97.5 + 5.1, 0.76 + 0.12 vs 1.07 + 0.23, P<0.05). The expression of Bcl-2 and Bax and the ratio of Bcl-2/Bax were similar in the control group, AST group and AST+ADR group.CONCLUSIONS:Primary cultured cardiomyocytes in newborn rats were protected by AST from injury of adriamycin by decreasing the activity of LDH, increasing the activity of SERCA, preventing the loss of ATm, promoting the expression of Bcl-2 and inhibiting the expression of Bax.