Abstract: Objective  To study the effects of apolipoprotein A5(ApoA5), apolipoprotein C3(ApoC3) and apolipoprotein A5/C3(ApoA5/ApoC3) on the blood lipid level,  occurrence of coronary heart disease (CHD) and the number of CHD branch,  so as to prevent the occurrence and progress of CHD by adjusting the apolipoprotein level.Methods  The age, gender, body mass index(BMI) and smoking status of patients of CHD and nonCHD group  were counted, the total cholesterol (TC), triglyceride(TG), high density lipoprotein (HDL) and low density lipoprotein (LDL) levels of  two groups were measured.The serum levels of ApoA5 and ApoC3 were determined by enzymelinked immunosorbent assay(ELISA), respectively, and ApoA5/ApoC3 ratio was calculated.  Risk factors were stratified according to TG level, and the   differences in ApoA5,  ApoC3,  and ApoA5/ApoC3 ratio  among nonCHD group,  high TG group and normal TG group of CHD group  were compared. The correlations between serum ApoA5,  ApoC3,  ApoA5/ApoC3 ratio and the number of CHD branch and various indexes were studied.Results   There were  statistically significant differences in gender and TG level between two groups (P<0.01). ApoA5 and ApoA5/C3 ratio  of high TG group and normal TG group were obviously lower than those of  nonCHD group,  and the level of ApoC3 of  high TG group was significantly higher than that of nonCHD group (P<0.01).  ApoA5 and ApoA5/C3 ratio  of  high TG group were lower than those of normal TG group,  and ApoC3 of high TG group was significantly higher than that of  normal TG group (P<0.01). Multivariate binary Logistic regression analysis showed that TG was an independent risk factor for the reduction of ApoA5 and ApoA5/C3 levels（OR=0.039，95%CI［0.009，0.157］，Wald 20.641, SE 0.716, P<0.01; OR=0.074，95%CI［0.023，0.134］，Wald 19.650, SE 0.588, P<0.01）,  TG was the independent protective factor for the rise of ApoC3 level(OR=9.084，95%CI［3.054，27.022］，Wald 15.736, SE 0.556, P<0.01); Serum level of ApoA5 and ApoA5/C3 ratio  were negatively correlated with TG,  while the level of ApoC3  was positively correlated with TG. Conclusion  ①Serum ApoA5  level and ApoA5/ApoC3 ratio were negatively correlated with the CHD occurrence, while the level of ApoC3 was positively correlated with CHD occurrence.Serum ApoA5 and ApoC3 were  respectively protective factor  and risk factor for CHD. And ApoA5/ApoC3 ratio reflected the degree of coronary artery lesion to a certain extent and could be used as a basis for estimating the CHD severity. ②TG level was an independent risk factor for the decrease of serum ApoA5 level and ApoA5/ApoC3  ratio,  which was negatively correlated with serum ApoA5  level and  ApoA5/ApoC3 ratio. However,  TG level was a protective factor for the increase of ApoC3 level,  which was positively correlated with ApoC3 level.

Key words: coronary disease, apolipoprotein A5, apolipoprotein C3, apolipoprotein A5/C3 ratio;correlation