ABSTRACT
Objective To investigate the influence of Schizandrain B(Sch B)preconditioning in myocardial cells of neonatal rats with hypoxia/reoxygenation (H/R)inj ury, and to explore its possible mechanism.Methods The cultured myocardial cells were divided into control group, model group and 10, 50, 250 mg · L-1 SchB preconditioning groups.All the cells in various groups except control group were cultured in 2 mmol·L-1 Na2 S2 O4 for 2 h,then cultured in normal medium for 18 h to induce myocardial H/R injury.The morphological changes of myocardial cells in various groups were observed under inverted microscope. The survival rates of the myocardial cells in each group were examined by MTT. The activities of lactic dehydrogenase (LDH ), creatine (CK ), superoxide ismutase(SOD),and the (MDA)levels in the cells in various groupswere examined by detection kits. Results Compared with control group,the cells in model group were retracted,arrest or float,the survival rate was decreased significantly (P<0.01),the activities of LDH,CK and MDA level were increased (P<0.01),and the SOD activity was decreased (P<0.01);compared with model group,the cells in Sch B preconditioning groups remained beating,retraction was light,the cell survival rates were significantly increased (P<0.01),the activities of LDH,CK and MDA levels were decreased (P<0.01),and the SOD activities were increased (P<0.05 or P<0.01).Conclusion Sch B has protective effect on myocardial cells with H/R injury in the neonatal rats,which may be associated with anti-oxidative damage.
ABSTRACT
In this paper,heart rate (HR) and heart rate variability (HRV) are extracted from ECG,and the five indexes in both time and frequency domains are analyzed.The result shows that the standard deviation (SDNN) of R-R intervals,the value of total power (TP),the power value of low frequency (LF) of HRV and the value of LF/HF increase obviously,while the power value of high frequency (HF) decreases markedly after fatigue.The physical fatigue level is classified according to the rate of increase and decrease of the indexes above.It is suggested that these five ECG indexes be used to reflect and evaluate the degree of physical fatigue quantitatively.