[Effects of interval training on calcium transient and contractile function of single ventricular myocyte in myocardial infarction adult rats].

OBJECTIVE

To investigate the effects of interval training on calcium transient and contractile function in ischemic ventricular myocytes of rats with myocardial infarction and their synchronization.

METHODS

Twenty-four male sprague-dawley rats in three years old, were randomly divided into three groups (n=8): sham-operated group(S), sedentary MI group(MI) and MI with interval training group (ME). The MI model was established by ligation of the left anterior descending coronary artery. The rats in ME group started training 1 week after MI operation. The S model was established by threading only without ligation. ME model took one week adaptive training, 10 m/min and 30 min/d, then took subsequently 8-week aerobic interval training: 10 min×10 m/min, then reran the rats with 2 intensities 15 m/min×6 min and 25 m/min×4 min, 1 h/d, 5 d/week. After training 24 hours, the cardiomyocytes of all groups were isolated by using the Langendorff fusion system. The contractile function and calcium transient of single ventricular myocyte in myocardial infarction adult rats were detected by IonOptix. Calcium transients were measured as [Ca2+]i amplitude, departure velocity, ratio, TTB50％, TTP and TTP50%, return velocity and ratio amplitude. PTA, SL, ±dl/dtmax and SL shortening% were tested to evaluate contractility.

RESULTS

Compared with S, the levels of [Ca2+]i amplitude, departure velocity, ratio amplitude and return velocity, SL shortening%, PTA and ±dl/dtmax of MI were decreased(P＜0.01), the levels of TTP, TTP50% and TTB50% of MI were increased(P＜0.01); Compared with MI, the levels of departure velocity, ratio amplitude, return velocity and [Ca2+]i amplitude of ME were increased(P＜0.01), the levels of TTB50%, TTP and TTP50% of ME were decreased(P＜0.01, P＜0.05). The levels of SL shortening%, PTA and ±dl/dtmax of ME were increased(P＜0.01, P＜0.05).

CONCLUSION

Interval training can improve calcium transient and contractile function of single ventricular myocyte in myocardial infarction adult rats.