Protective Effect Of Slit2-Robo4 On The Cardiac Injury Of Rats With Sepsis

Objective:To study the protective effect of Slit2-Robo4 on the cardiac injury of rats with sepsis,providing theory evidence on the treatment of sepsis with medicine.Methods:The rats were randomly divided into six groups.Including sprague dawley rats in control group(ANS),sprague dawley rats with sepsis group(ALPS),sprague dawley rats with Slit2 protein injection group(ASLPS),Robo4-/-rats in control group(RNS),Robo4-/-rats with sepsis group(RLPS),Robo4-/-rats with Slit2 protein injection group(RSLPS).The six groups of the latter were decomposed into seven subgroups according to the time of exposure to Escherichia coli endotoxin(LPS)used in the animal model(2h,4h,6h,12h,24h).Rats in the ANS group and RNS group were injected normal saline intraperitoneally.Rats in the ALPS group and RLPS group were injected Escherichia coli endotoxin(5 mg/kg)intraperitoneally to make sepsis rats model.Rats in the ASLPS group and RSLPS group were preprocessed with Slit2-N before injecting LPS to make sepsis rats model.At the corresponding time of points,observing the general state in health of the rats,and the hearts were isolated for morphologic pathology.Cardiac functions parameter were detected with a ventricular catheter in the left ventricle of rats.The microvascular permeability in the heart were measured using evans blue fluorometric method.Plasma levels of inflammatory cytokines,including TNF-α,IL-1β,and IL-6,were detected by EILSA kits.The distributions of TNF-α,IL-1β,IL-6 and CD51 in the heart were decected by immunohistochemistry.The expression level of SLIT2 and ROBO4 in myocardium were measured using western blotting.According to traditional Chinese medicine theory,from the point of view of the disease and the actual conversion of the two points of view of the actual situation of sepsis rats were observed.Result:There is a high mortality in the ALPS group and RLPS group,histopathology of the heart changed obviously and the microvascular permeability in the heart raised up especially in the 6h compared with ANS group and RNS group(P<0.05),and the left ventricular diastolic and systolic functions decreased significantly(P<0.05).Compared with the control group,the inflammatory cytokines TNF-α,IL-1β,and IL-6 increased significantly(P<0.05),and increased first then decreased.There were significant differences in TNF-α and IL-6 between RLPS group and ALPS group at 2h,IL-1β at 6h and 24h.After injection of Slit2,There is a high mortality in the RSLPS group,and no significant difference wihe RLPS group,histopathology of the heart changed obviously and the microvascular permeability in the heart raised up compared with RNS group and ANS group(P<0.05).TNF-α increased obviously at 2h,and IL-1β,IL-6 increased in the first but declined soon after.There were significant differences in TNF-α at 2h,IL-1β at 6h and 24h,IL-6 at 4h and 6h between RLPS group and ALPS group(P<0.05).There were no significant differences in TNF-α、IL-1β at 4h and 6h,IL-6 at2h and 4h between RSLPS group and RLPS group(P>0.05),but there were statistically significant differences in myocardial tissue(P<0.05).Injection of Slit2 can enhance the expression of Slit2 protein in cardiac tissue,sepsis can increase the expression of Robo4,the difference is statistically significant(P<0.05).There was no significant difference between the two groups in the change of the pathogenesis of sepsis rats(P>0.05).There was statistically significant differences between ASLPS12h group and other groups of the exterior and interior(P<0.05).Conclusion:1.Slit2-N can decrease microvascular permeability in the heart of SD rats,restrain Inflammatory reaction,improve cardiac functions,strengthen protein level of Slit2.These demonstrate Slit2-Robo4 can protect the heart in sepsis.2.Slit2-N can not decrease microvascular permeability in the heart of Robo4-/-rats,It suggests that Slit2 may be involved in the role of Robo4 gene.It also suggests that Robo4 gene may have a protective effect on cardiac function.3.Slit2-N can improve cardiac functionsy of Robo4-/-rats,It suggests that it will be in other ways can improve the cardiac function of Slit2 in addition to Robo4.4.Slit2-N can not inhibit the levels of serum inflammatory cytokines,can partially inhibit the expression of inflammatory factors,but can not inhibit the expression of inflammatory factors after Robo4 gene knockout.It Suggest that the Slit2-Robo4 pathway maybe has a protective effect on myocardial injury.5.Robo4 knockout don’t change the actual pathogenesis change of traditional Chinese medicine with sepsis rats.6.Slit2-N can accelerate the outcome of the disease from the inside out.