Objective: To observe the effects of repeated + Gz exposures on the apoptosis of myocyte in rats.
Methods: Twelve male Sprague-Dawley rats were randomly divided into three groups: Control group, + 6Gz group and + 10Gz group. The rats of + Gz groups were exposed to + 6Gz for 3 min, + 10Gz for 3 min respectively, 1 b/d, 1 week. Four control rats were kept at the Earth gravity (1G) in the room with the centrifuge. All animals were anaesthetized and anatomies 1 day after the last exposure. Ventricular myocardium was studied by electron microscopy and terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) method.
Results: The apoptosis of myocyte in control group and + 6Gz group were scarcely observed by electron microscopy, while heterochromatin concentration and margination were observed in + 10Gz group. The apoptotic index of myocardium increased significantly in + 6Gz and + 10Gz group compared with that of the control group (P < 0.05) and showed the largest value in the + 10Gz group (P < 0.05).
Conclusion: Repeated + Gz exposures may induce apoptosis in myocyte, and the number of apoptosis in myocyte increases gradually with the increase of G value.