Effect of heat shock protein 70 expression induced by glutamine on vascular hyporeactivity in rats caused by LPS

AIM: To observe the effect of heat shock protein 70(HSP70) expression induced by glutamine on Escherichia coli lipopolysaccharides(LPS)-induced vascular hyporeactivity in rats.METHODS: Twenty four healthy male Sprague-Dawley rats were randomly divided into: the control group (n=8);LPS shock group (n=8);glutamine(Gln) treated group (Gln 0.75 g·kg-1 iv,n=8).6 h after LPS shock,phenylephrine (PE,0.5-2.5 μg·kg-1 ) was applied intravenously to all groups and the percentage increase in mean arterial pressure(MAP) was detected,respectively.The concentration-response curves of aorta rings were obtained by cumulative addition of phenylephrine (PE),and PE Emax,EC50 were calculated.The blood concentration of malondialdehyde (MDA),TNF-α and IL-6 were assayed in all groups 30 min and 360 min after LPS shock,respectively.The expressions of HSP70 from heart and aorta were also assayed after 6 h LPS shock.RESULTS: The MAP level induced by PE significantly decreased by 51.4% in LPS shock group compared with the control (P<0.05).However,PE induced MAP level increased by 17.5% in Gln group compared with LPS shock group (P<0.05).Emax and EC50 to PE were significant reduced in LPS shock group compared with control group (P<0.05),but significantly improved in Gln group (P<0.05).The expressions of HSP70 from heart and aorta were much higher in Gln group than those in LPS shock group (P<0.05).The blood concentrations of TNF-α,IL-6 and MDA were much lower in Gln group than those in LPS shock group.CONCLUSION: Glutamine effectively improves α-adrenergic receptor-mediated vascular reactivity through inducing the expression of HSP 70,reducing inflammatory cytokine release and peroxide biosynthesis in LPS shock.These results suggest that glutamine have potential beneficial therapeutic effect for septic shock patients.