[Effects of low-G preconditioning on contractive ability of left ventricle and contents of endothelin and prostacycline in myocardium of rats after repeated +10 Gz stress].
OBJECTIVE
To further test the protective effect of low-G pre-conditioning on +Gz stress induced cardiac damage.


METHODS
Forty-two male Wistar rats were randomly divided into 3 groups (n=14 for each group): group A (+1 Gz group), group B (+10 Gz group) and group C (low-G pre-conditioning group). The rats in group B were exposed to five +10 Gz plateaus of 30 s with 1 min intervals at +1 Gz, 3 times a week, for 3 weeks; while group A were only submitted to +1 Gz for 5 min. The rats in group C were exposed to +2 Gz for 5 min about 1 h prior to +10 Gz stress. All the animals were decapitated in the next day after the last centrifuge run and function of the isolated working hearts and contents of endothelin and prostacycline in the myocardium were observed.


RESULTS
Compared with the control, a significant decrease of left ventricular systolic pressure (LVSP) and increase of myocardial contents of endothelin in rats were observed after repeated +10 Gz exposure; but low-G pre-conditioning could remarkably elevate the LVSP and reduce the myocardial endothelin level in rats after repeated +10 Gz stress.


CONCLUSIONS
Low-G pre-conditioning has a significant protective effect on contractive ability of the left ventricle and secretion function of the vascular endothelium in rat heart after high G stress.
Medical Division, Peking University, Beijing, China.
Feng-Ying
FY
Fu
Hao
H
Zhan
Zheng
Z
Zhang
Tong
T
Li
Yi-Mei
YM
Xin
Si-Huang
SH
Wei
D000054:Acceleration; D000818:Animals; D002498:Centrifugation; D016232:Endothelins / Q000378:metabolism; D004730:Endothelium, Vascular / Q000502:physiology; D011464:Epoprostenol / Q000378:metabolism; D018471:Hypergravity; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D016276:Ventricular Function / Q000502:physiology*
D016232:Endothelins; D011464:Epoprostenol