Effects of Taurine on Myocardial cGMP/cAMP Ratio, Antioxidant Ability, and Ultrastructure in Cardiac Hypertrophy Rats Induced by Isoproterenol - Advances in Experimental Medicine and Biology - page 202

Chapter 21
Effects of Taurine on Myocardial cGMP/
cAMP Ratio, Antioxidant Ability,
and Ultrastructure in Cardiac Hypertrophy
Rats Induced by Isoproterenol
Qunhui Yang , Jiancheng Yang , Gaofeng Wu , Ying Feng ,
Qiufeng Lv , Shumei Lin , and Jianmin Hu
Abstract Taurine is the most abundant free amino acid in the human body and
accounts for more than 50% of the total amino acid pool in the mammalian heart. To
investigate the preventive effects of taurine on cardiac hypertrophy in rats, myocar-
dial injury was established by hypodermic injection of isoprenaline (ISO) (10 mg/
kg d) for 7 days. The preventive effects of taurine (100 mg/kg d, 200 mg/kg d, and
300 mg/kg d, i.p) on heart coefficient; ultrastructure of cardiac muscle; the levels of
creatine kinase heart isoenzyme (CK-MB), cAMP, and cGMP; and antioxidant abil-
ity were investigated. The results showed that taurine could significantly prevent the
increase of heart coefficient induced by ISO. Compared with the model group,
100 mg/kg and 200 mg/kg taurine significantly decrease the levels of cAMP and
cGMP, while 300 mg/kg taurine could significantly decrease the levels of cAMP in
myocardium, and all the three concentrations of taurine could significantly increase
the ratio of cGMP/cAMP. The level of serum CK-MB was significantly increased
by ISO; 200 mg/kg taurine could significantly decrease it, but 100 mg/kg and
300 mg/kg taurine had no significant effect. As for the antioxidant ability, ISO
administration could significantly increase the myocardial level of MDA but had no
significant effects on the myocardial levels of SOD, GSH, GSH-Px, and T-AOC.
However, taurine administration could significantly decrease the myocardial level
of MDA and increase the levels of GSH and T-AOC compared with the model
group. The serum levels of SOD, GSH-Px, GSH, and T-AOC were significantly
reduced by ISO administration, but the level of MDA showed no significant changes
compared with the control group. Taurine administration could significantly increase
the serum levels of SOD, GSH-Px, GSH, and T-AOC and decrease the level of
MDA compared with the model group. All the results indicated that 200 mg/kg
taurine had better effects. The ultrastructure of cardiomyocytes showed that taurine
administration could significantly reverse the injury caused by ISO. In conclusion,
Q. Yang ￿ J. Yang ￿ G. Wu ￿ Y. Feng ￿ Q. Lv ￿ S. Lin ￿ J. Hu ( * )
College of Animal Science and Veterinary Medicine, Shenyang Agricultural University,
Shenyang 110866 , P.R. China
e-mail: [e-mail]