Study Of Protective Effects Of Epigallocatechin Gallate Preconditioning On Myocardial Cells Anoxia/Reoxygenation Injury And Intracellular PI3-K/Akt Signal Pathway

Objective: Establish neonatal rat myocardial cells anoxia/reoxygenation (A/R) injury model. To explore the protective effects and the mechanisms of epigallocatechin gallate (EGCG) preconditioning on neonatal rat myocardial cells A/R Injury. Methods: Cultured myocardial cells of SD neonatal rats(1～3 d), and then randomly divided into three groups after cultured 48 hours: control group, anoxia/ reoxygenation group (A / R group) , EGCE preconditionging group(EGCG+ A / R group). At the end of experiment , measured cell viability and the amount of released lactate dehydrogenase (LDH) by a colorimetric method; Apoptosis of myocardial cells was detected by Annexin-V/PI assays with flow cytometry; The expression of t-Akt and p-Akt protein in cytoplasm were measured by western blotting. Results : 1. The cell viability: the cell viability of A/R group (45.79±3.98%) significantly decreased when compared with that of control group (93.62±3.01%) and EGCG+ A/R group (73.86±4.78%)(p<0.01, respectively); The viability of EGCG+ LY294002+ A/R group(49.62±4.83%)was no significant difference compared with that of A/R group respectively(p>0.05), While the difference between that of EGCG+ A/R group was significant(p<0.01). 2. LDH activity: the activity of LDH in A/R group(31.96±3.12 U/L)significantly increased compared with that in control group(4.06±0.51 U/L()p<0.01);the activity of LDH in EGCG + A/R group (17.46±1.91 U/L) significantly decreased compared with that in A/R group(p<0.01); the activity of LDH was no significant difference between EGCG+ LY294002+ A/R group(29.52±2.62 U/L)and A/R group (p>0.05), While the difference between that of EGCG+ A/R group was significant(p<0.01). 3. Cell apoptosis levels: the apoptosis levels of A/R group(19.32±1.54%)noticeably increased compared that of control group(5.24±0.86%)and EGCG+ A/R group(9.68±1.12%)(p<0.01, respectively); the apoptosis levels of EGCG+ LY294002+ A/R group(17.62±1.48%)was no significant difference compared with A/R group, While compared with EGCG+ A/R group, the the apoptosis levels was significantly decreased(p<0.01). 4. Expression of t-Akt and p-Akt protein: the expression of t-Akt protein was no noticeably difference in all group (p>0.05,respectively). The expression of p-Akt protein in EGCG+ A/R group was significantly increased compared that of A/R group(p<0.01); while the expression of p-Akt protein in EGCG+ LY294002+ A/R group was significantly decreased compared with EGCG+ A/R group(p<0.01). Conclusion: Our research showed that EGCG could protect cardiomyocytes against A/R injury, the antagonist effect on myocardial cells injury induced by A/R was mediated by activation of intracellular PI3K-Akt signal pathway.