Objective:To elucidate the etiology of the impairment of myocardial cells in Keshan disease. Methods:With intracellular microelectrode technique, we observed the electrophysiological changes of the eight groups of rats fed separately:normal, low Se, low Se+high VC, low Cr, low Cr+high VC, low Se+low Cr and low Se+low Cr+high VC fodders. Results:Compared with the control, there was no change in low Cr group. However, in low Se group, RP and APA decreased, APD 50 and APD 90 prolonged. In low Se+low Cr group, APA decreased, APD 50 and APD 90 prolonged significantly. In low Se with high vitamin C groups, though RP still decreased, no change had been detected on APA and APD. Conclusion:It is suggested that Se and Cr deficiency may jointly change the electrophysiological properties of myocardial cells significantly. However, vitamin C may protect myocardial cells against the injury effectively.

Objective: To observe the effects of vitamin C(VC)on the electrophysiological property of myocardial cells of the rats fed with low selenium and high cadmium fodder. Method: Eight groups of rats were fed separately with: normal (2 groups), high Cd, high Cd+high VC, low Se+high Cd, low Se+high Cd+high VC, high Se+high Cd and high Se+high Cd+high VC fodder for 14 w. With intracellular microelectrode technique, the electrophysiological changes of rats were observed. Results:Compared with the control, there were no changes in high Cd+high VC group and in high Se+high Cd+high VC group. However,in high Cd group, RP and APA decreased, APD50 and APD90 prolonged; in low Se+high Cd group ,RP and APA decreased, APD50 and APD90 prolonged significantly; in low Se+high Cd+high VC group and high Se+high Cd group, though RP still decreased, no change had been detected on APA and APD. Conclusion: Se deficiency and simultaneous Cd overabundance may change the electrophysiological properties of myocardial cells of the rats significantly. However, VC may protect myocardial cells against the injury effectively.