Research On The Effect Of Hyperlipidemia On Choroidal Blood Vessels

PURPOSES To investigate the expression of VEGF and ultrastructure changes in the choroidal blood vessels of hyperlipidemia rabbits,to explore the role of hyperlipidemia in the pathogenesis of CNV in ARMD.METHODS 36 rabbits were divided randomly into 2 groups,normal control group and hyperlipidemia group by feeding respectively standard diet and high cholesterol diet. The ultrastructure changes in the choroidal blood vessels were observed by the transmission electronic microscope and the expression of VEGF was analysed with immunohistochemical method and RT-PCR at 1,2,3 months.RESULTS1.Ultrastructure changes of choroidal blood vessels:No abnormal change was found in the control group.Different degrees of ultrastructural lesion was found in the hyperlipidemia group during the course,the VECs were swollen and discontinuous,the basal membrane was fragmentally thickened,the blood vessels were narrowed and even blocked,the foam cells and lipid were found on the vascular dissepiment.2.Immunohistochemical method showed that the expression of VEGF was weak in normal control group and the difference was statistically nonsignificant among group C1,C2 and C3 (P>0.05).The expression of VEGF was enhanced in hyperlipidemia group and the difference was statistically significant compared group G2,G3 with group C2(P<0.05),C3(P<0.01),nonsignificant compared group G1 with C1 (P>0.05).3.RT-PCR showed that VEGFmRNA was detected in both normal control group and hyperlipidemia group.The expression of VEGFmRNA paralleled to the result of immunohistochemical method.CONCLUSION The lesion in the endothelial cells of choroidal blood vessels and enhanced expression of VEGF caused by hyperlipidemia might lead to CNV.