Expression Of CD36 And CPT-1 On Cardiomyocytes After The Acute Period Following High Level Spinal Cord Injury In Rats

Objectives To observe the expression of fatty acid transporter(CD36)and carnitine acyltransferase 1(CPT-1)on cardiomyocytes after acute period following high level spinal cord injury(SCI)in rats,and preliminary to discuss the role of fat acid metabolism in cardiomyocytes after high level spinal cord injury.Methods 1.Thirty-six healthy male Sprague-Dawley rats,weighing 250-300 g,were randomly divided into six groups(n = 6): the control check group(CK group),the sham-operation control group(Sham group),4h after high spinal cord injury group(SCI 1 group),12 h after high spinal cord injury group(SCI 2 group),24 h after high spinal cord injury group(SCI 3 group)and 48 h after high spinal cord injury group(SCI 4 group);2.The rats in the group of SCI were treated by a modified Allen's combat method.The postoperative features were investigated and recorded and the myocardium tissue was taken at each time point for the further test;3.Transmission electron microscopy is used to assess ultrastructure in the myocardium;4.The contents of CD36 and CPT-1 in cardiomyocytes were detected by Western blot assay;5.Expression of CD36 in cardiomyocytes was detected by fluorescence quantitative PCR.Results 1.In SCI groups,the spinal cord became gray immediately,the activity decreased after operation,the lower limbs were paralyzed,the respiration was shallow and fast,the food intake was decreased,the spontaneous urination and defecation are disappeared.The rats in Sham group were normal after operation;2.The results of transmission electron microscope showed that the myocardial structure of Sham group was still perfect.Compared with CK group,there were no significant abnormalities.In SCI groups,myocardial myofilament dissolution,extracellular reticular stent structure collapse,submembrane lysosome aggregation and mitochondrial structure destruction were observed.3.The contents of CD36 and CPT-1 in cardiomyocytes of SCI groups increased at first and then decreased,and the contents in SCI 1 group were significantly higher than those in Sham group(P<0.05),and those in SCI 4 group were lower than those in SCI 4 group.Compared with Sham group,there was significant difference(P<0.05),but there was no significant difference between SCI 2 group and SCI 3 group and Sham group.4.The results of PCR showed that there was no significant difference in the expression of CD36 mRNA between Sham group and CK group(P>0.05).The expression of CD36 mRNA of cardiomyocytes in SCI groups increased at first and then decreased.The expression in SCI 1 group was significantly higher than that in Sham group(P<0 05),and decreased in SCI 4 group,which was significantly lower than that in Sham group(P<0 05),but there was no significant difference between SCI 2 group and SCI 3 group compared with Sham group.Conclusions 1.The ultrastructural changes of myocardial cells appeared in acute phase after high spinal cord injury in rats,suggesting the existence of myocardial injury.2.The abnormal expression of CD36 and CPT-1 in acute phase after high spinal cord injury in rats suggests that the fatty acid metabolism pathway is disordered,which may be an important mechanism of myocardial injury caused by energy metabolism disorder of cardiomyocytes after acute period following high level spinal cord injury.