Influence Of Lycium Barbarum Polysaccharides On Arterial Compliance At High Temperature Of Exhaustive Exercise Rats

Objective The purpose of this study was to evaluate the effect of Lycium barbarumpolysaccharides （LBP） associated with exercise fatigue on arterial compliance at hightemperature in rats. We next explored the possible mechanism of high strength and intensity-induced impaired cardiovascular function in exhaustive swimming rats. Therefore, it can bebetter to provide experimental evidence and theoretical guidance for the further developmentof Lycium barbarum medicinal value.Methods60adult males were selected and divided randomly into4groups （n=10each group）: control sedentary group （CS）; aerobic exercise group （AS）; normal temperatureexhaustive exercise group（ES）; normal temperature exhaustive exercise that received LBPgroup（ES+LBP）; exhaustive exercise group at high temperature（ESH）; exhaustive exercisegroup at high temperature that received LBP（ESH+LBP）.We constructed a four weekswimming exercise protocol in rats, and measured the time until exhaustion, the blood levelsof malondialdehyde （MDA）, super oxide dismutase （SOD）, nitric oxide（NO）, heat shockprotein70（HSP70） and skeletal muscle ATP enzyme activity. The expression levels of eNOSmRNA in aorta rings were detected by real-time quantitative PCR. A tension of aorta ringswas measured to evaluate the response on noradrenaline （NA）-induced contraction.Results The body weight of rats in LBP treated groups were notsignificantly different from that in the normal control group before and after the experiment（P>0.05）. Compare with the group of the exhausted rats, the LBP treated groups weresignificantly prolonged the mean endurance time to exhaustio（nP＜0.01）. LBP treated groups at high temperature is longer than the normal group, but there is no significant differencebetween normal and high temperature that received LBP groups. The exhaustive swimmingexercise significantly increased the vasoconstrictive response to NA compared with the LBPtreated groups （P<0.01）. The contractile responsiveness of exhaustive exercise group at hightemperature that received LBP to NA was significantly lower than that of exhaustive exercisegroup （P<0.01）, while compare with the control sedentary group, exhaustive exercise groupssignificantly increased the vasoconstrictive response to NA （P＜0.01）. Compare withexhaustive exercise group, high temperature exhausted swimming group decreased thevasoconstrictive response to NA, but there was no significant difference （P>0.05）. LBPtreated groups promote increase the activities of SOD, NO and HSP70levels in plasma（P＜0.01）. Compare with the normal temperature exhaustive exercise group and normaltemperature exhaustive exercise that received LBP group, the SOD level of control sedentarygroup is significantly higher, but there is no significant difference among them（P＞0.05）.The SOD activities and content of HSP70in control sedentary group are higher than theexhaustive exercise groups that at normal and high temperature（P＜0.01）. Compare with thegroup of the exhausted rats, the activities of MDA, LD are significantly lower in the LBPtreated groups（P＜0.01）. The MDA activities in control sedentary group are lower than theexhaustive exercise group that at normal and high temperature（P＜0.01）. LBP treated groupsincrease the activities of Ca²⁺-ATP enzyme levels in skeletal muscle（P＜0.01）. And theCa²⁺-ATP enzyme level of control sedentary group is higher than the exhaustive exercisegroups that at normal and high temperature, but there is no significant difference among them（P＞0.05）. LBP treatment group significantly enhanced the expression of eNOS mRNA inthoracic aortas compared with that in the exhaustive exercise groups which at normal andhigh temperature （P<0.01）. The expression of eNOS mRNA in control sedentary group ishigher than the exhaustive exercise groups （P<0.01）.Conclusion LBP can improve the anti-fatigue ability at high temperature of exhaustive swimming exercise rats. In addition, LBP attenuate the contractile responses to NA andimprove the vascular elasticity.