Protection of Branched-Chain Amino Acids Against Ischemic Myocardial Injury in Rats

The protective effects of Branched-Chain Amino Acids (BCAA) on ischemic myocardium in rats were studied. Thirty Wistar rats (15 female and 15 male) were rmdomly divided into 3 groups of 10 animals each. Group A: control; group B: isoproternol (ISO); group C: ISO + BCAA. The rats in groups A and B received normal synthetic rat chow while those in group C received BCAA as supplement. After two weeks of dietery treatment, the rats in group A were injected with salinewhile those of groups B and C were injected with ISO which induced acute ischemic myocardial in-jury. After 4 days of injections with either saline or ISO, the rats were sacrified. The activities of lactate dehydrogenase (LDH), glutamic oxaloacetic transaminase (GOT), α-hydroxybutyrate dehy-drogenase (a-HBDH), creatine kinase (CK), pyruvate kinase (PK) in the serum and in the my-ocardium, and the concentrations of potassium (K+ ), magnesium (Mg2+ ), calcium (Ca2+ ) in themyocardium were measured. The results showed that the activities of LDH, GOT, α-HBDH, CK,PK in the serum and in the myocardium were significantly increased in group B. In addition, the concentraions of Ca2+ in the myocardium were significantly increased. However, the concentraions of Mg2+ in the myocardium were substantially decreased while those of K+ in group B were slighily lowered. In the group C animals both the activities of LDH, α-HBDH, PK, CK in the serum and the activities of LDH, GOT, α-HBDH, CK in the mycardium were sighficandy lower than those of the rats in group B, and were not sighficantly different from those of the control group. More signif-icant was the concentrations of Ca2+ in the myocardium of the rats in group C were compeble to those of the control rats but were significantIy lower than those of the rats in group B. It appeared that BCAA was effectively blocking the increase of Ca2+ in the myocardium without talsing the levelof Mg2+. It was concluded that dietary supplement with BCAA provided some protective effects a-gainst ischemic myocardium in rats