Effects of GATA-4-specific RNAi on GATA-4 and cTnI expression in H9c2 cells. H9c2 cells were transfected with siRNA specific to GATA-4 (RNAi) or scrambled RNA (Scr) for 24 hr and then exposed to 30 mmol/L glucose for another 24 hr. Whole cell lysates were isolated for Western blot analysis of GATA-4 (A) and troponin I (B) protein expression. H9c2 cells cultured in regular medium were used as the control (Con). The results are presented as the mean ± SEM (n = 3-5 per group). *P < 0.05, **P < 0.01 as compared with the high glucose-treated group.