Objective To investigate the clearance capacity of cardiac resident macrophages in post-sepsis and its underlying mechanism.Methods A mouse model of sepsis was established using cecum perforation ligation.Thirty male C57BL/6 mice(8 weeks old,weighing 20～25 g)were randomly and equally divided into a sham operation group(sham group)and a model group(sepsis group).Immunofluorescence assay was employed to label the cardiomyocytes and macrophages to observe the apoptosis of cardiomyocytes and the phagocytosis by cardiac resident macrophages.Cardiac resident macrophages were extracted for transcriptomic sequencing to determine the functional changes of the cells after sepsis.Cardiac resident macrophage cell lines were established at the cellular level and served as the normal group(RAC group),and the RAC cells treated with LPS were subjected as the sepsis group(RAC+LPS group).Then the differences in the ability to clear apoptotic cardiomyocytes between the 2 groups were observed.Then DQ-BSA-RED lysosomal activity detection probe,Lyso-Sensor yellow/bule dye,ELISA,and Western blotting were applied to detect the lysosomal function of cardiac resident macrophages,activity and expression of important lysosomal hydrolases,changes in contents and related subunits of vacuolar-type adenosine triphosphatases(V-ATPase).Results Compared with the sham group,the sepsis group had larger number of apoptotic cardiomyocytes(P＜0.05)and increased phagocytosis of cardiomyocytes by cardiac macrophages(P＜0.05).The results of transcriptomic sequencing revealed a significant dysfunction of lysosome-associated functions of cardiac-resident macrophages after sepsis.In in vitro experiments,the RAC+LPS group had a reduced fragmentation capacity of apoptotic cardiomyocytes,reduction in the intensity of yellow fluorescence of lysosomes(P＜0.05),and decrease in lysosomal hydrolase activity(P＜0.05)when compared with the RAC group.In addition,LPS treatment significantly decreased the activity and expression of V-ATPase and its major subunit ATP6V1A in cardiac resident macrophages(P＜0.05).Conclusion Cardiac resident macrophages show reduced clearance of apoptotic cardiomyocytes after sepsis,which may be related to a decrease in the activity of ATP6V1A,an important subunit of its lysosomal V-ATPase,and reduced activity of lysosomal hydrolases.

Objective To observe the improved effect of propofol on vascular hyporeactivity in septic rats and its underlying mechanism.Methods A total of 96 SD rats(12 weeks old,both genders,weighing 200～220 g)were randomly divided into sham group(n=16),sepsis group(n=16,cecal ligation and puncture),propofol group(n=16),propofol+ROCK inhibitor Y-27632 group(n=16),propofol+PKCαinhibitor GO6976 group(n=16),propofol+IP3 inhibitor 2-APB group(n=8)and propofol+gap junction inhibitor metoclopramide sodium(Movens)group(n=8).In vitro vascular ring reactivity and vascular calcium sensitivity were measured to observe the improved effects of propofol on vascular hyporeactivity in septic rats and its relationships with RhoA/ROCK,PKCα,IP3 and cell gap junction.Results Determination of in vitro vascular ring and calcium sensitivity showed that the contractile reactivity to norepinephrine(NE)and to calcium sensitivity were significantly decreased in the arterial rings isolated from the septic rats compared with those from the sham group,with the dose-response curve shifting to the right,and most significant decrease by 51.42％in the superior mesenteric artery(SMA,P＜0.05).Propofol treatment significantly improved the hyporeactivity and calcium sensitivity of the vessels isolated from the septic rats,especially those of the femoral artery with a recovery rate of 89.57％(P＜0.05).In comparison with the propofol group,the dose-response curves of the propofol+Y-27632 group and the propofol+GO6976 group were shifting to right,indicating that Y-27632 and GO6976 could significantly inhibit the amelioration of propofol on calcium sensitivity of SMA in severely septic rats with an inhibitory rate of 146.95％and 88.63％(P＜0.05),respectively.Isolated vascular reactivity measurement demonstrated that Y-27632 and Movens treatment significantly antagonized the ameliorated role of propofol on hyporeactivity of blood vessels from the septic rats with an inhibitory rate of 40.79％and 169.90％(P＜0.05),separately,while no such effect was observed in the propofol+GO6976 and propofol+2-APB groups.Conclusion Propofol treatment can significantly improve vascular hyporeactivity of septic rats,which may attribute to the increase of vascular calcium sensitivity through RhoA/ROCK pathway.