Study Of The Relationship Between β Integrins And Sepsis Induced Myocardial Injury In Rats

Objective To investigate the changes of the septic rat hearts, the dynamic changes of β integrins in septic rat hearts and its roles in sepsis induced myocardial injury.Methods Sprague-Dawle (SD) rats were randomly divided into two groups:control group and experimental group. Rats in experimental group were injected Escherichia coli endotoxin (LPS)(5mg/kg) intraperitoneally, and were divided into eight sub-groups, according to the time of exposure to LPS (1h,2h,4h,6h,12h,18h,24h,48h). Rats in control group were injected normal saline intraperitoneally. At the corresponding time of points, the hearts were isolated for morphologic pathology and sirius red staining, and cardiac functions, including left ventricular developed pressure (LVDP), left ventricular pressure maximal rate of rise (+dP/dt max), left ventricular pressure the maximum rate of descent (-dP/dtmax), myocardial oxygen consumption index (SPTI*HR) and left ventricular end diastolic pressure (LVEDP) were measured using left ventricular catheterization. Plasma levels of inflammatory cytokines, including TNF-α, IL-1β, and IL-6, were detected using EILSA kits. The expression of β1, P2, P3integrins in myocardium were measured using western blotting and immunohistochemistry.Result Hemodynamic changes occurred in the early stage of sepsis. LVDP,+dP/dt max,-dP/dtmax, SPTI*HR in experimental group decreased significantly, compared with those in control group. While, LVEDP in experimental group increased significantly. Plasma levels of TNF-a, IL-1β and IL-6was significantly increased, and reached the peak2h,6h,4h after LPS injection respectively. Histopathology of the hearts in LPS group shoued vacuolar degeneration, arranged in loose, structural disorder, interstitial collagen fibers decreased. Western Blot and IHC showed that the β1, β2and β3integrins in LPS group compared with control group changed significantly. In experimental group, β1integrin expression significantly increased first, reached a peak at6h, decreased after48h. β2integrin expression increased compared with the control group. While β3integrin expression decreased in experimental group, especially6h after LPS injection.Conclusion There were significant structural and functional changes in sepsis-induced myocardial injury and β integrins involved in the mechanisms of myocardial injury in sepsis rats.