The Lipid-lowering Effect And Possible Mechanism Of Apobec-1 Recombinant Adenovirus In Nephropathy Rabbits

ObjectiveTo observe the effect of liver acquired expression of apolipoprotein B editing catalytic polypeptide-1 (apobec-1) on blood lipid metabolism, Hepatic apobec-1, Hepatic apolipoprotein B48 (apoB48), Hepatic low density lipoprotein receptor (LDLR), and Hepatic low density lipoprotein receptor related protein (LRP) in nephropathy rabbits and to explore the lipid-lowering effect and possible mechanism.MethodsThe 30 healthy ordinary level male six months old new Zealand rabbits (approximately 1000-2000g) were randomly divided into three groups:sham operation group(n=10), nephropathy group(n=10), and apobec-1 treatment group(n=10) and fed in Metabolic cage. Adapt feeding for one week, the nephropathy group and apobec-1 treatment group were anesthetized with 30%pentobarbital of 30mg/KG by Intraperitoneal injection, then underwent left nephrectomy under sterile condition; The sham operation group was only explored to renal capsule, not resect the left kidney. One week later, adriamycin (4mg/KG) was used to construct the nephropathy model by ear vein injection in nephropathy group and apobec-1 treatment group, whereas the sham operation group was injected with physiological saline in equal amount. The eleventh week after operation, apobec-1 recombinant adenovirus (1×1013 Virus/KG) was injected by ear vein in apobec-1 treatment group, whereas the sham operation group also was injected with physiological saline in equal amount. The twelfth week after operation, all rabbits were sacrificed. Right kidney, liver, blood and 24 hour urine were left after Fasted for 12 hours, and then were sent to detect.24 hour urinary protein (24UPr) was detected by biuret colorimetric assay. Albumin (Alb), blood urea nitrogen (BUN), creatinine (Cr), total cholesterol(TC), total triglyceride(TG) and high density lipoprotein(HDL-C) was detected by enzymic method. Very low density lipoprotein(VLDL-C) and low density lipoprotein(LDL) were estimated by the Friedewald formula; Serum apolipoprotein B100(apoB100) and apolipoprotein B48(apoB48) were detected by radioimmunoassay. The removed kidneys were fixed by 10% neutral formalin after dried with filter paper, and then the renal pathology were observed by HE staining. The removed livers were clipped some tissue to set in EP tube, then preserved in-80℃ low temperature refrigerator, and expression of liver Apobec-1,ApoB48,LDLR and LRP were observed by Western blot in last. The band of Western blot was analyzed by relevant optical density. Then through the relevant optical density ratio of β-actin to reflect the expression of each protein indirectly. The date was displayed in x±s. Single factor analysis was used by SPSS 13.0 statistical software and pairwise comparison was used by the SNK-q test, the test of criterion of α=0.05.Results1. Comparison of blood and urine indexes of each group In the three groups, the difference of 24UPr,Alb,BUN,Cr,TC,TG,VLDL-C,LDL-C, ApoB100 and ApoB48 all have Statistical significance(P<0.05). Compared with the sham operation group, nephropathy group showed that 24UPr, BUN, Cr, total cholesterol (TC), total triglyceride (TG), very low density lipoprotein (VLDL-C), low density lipoprotein (LDL-C), apolipoprotein B100 (ApoB100) were increased(P<0.05), Alb was decreased(P<0.05), while HDL-C and ApoB48 had nothing change. Compared with nephropathy group, Apobec-1 treatment group showed that TC, TG, VLDL-C, LDL-C, ApoB100, ApoB48 were decreased(P<0.05), while 24UPr、Alb、BUN、Cr、HDL-C had nothing change. Compared with the sham operation group, Apobec-1 treatment group showed that 24UPr, BUN, Cr were increased(P<0.05), Alb, ApoB48 were decreased(P<0.05), while TC、TG、VLDL-C、LDL-C、HDL-C、ApoB100 had nothing change.2. Kidney pathological changes The renal tissue structure of sham operation group had nothing abnormal. The renal tissue structure of nephropathy group and Apobec-1 treatment group showed that renal tissue cell was hypertrophy and arranged in disorder; the glomerular capsule wall was thickening and some places had visible adhesions; renal interstitial was broadening, have a large number of matrix and inflammatory cell and some places had visible focal glomerular necrosis.3. Each group of hepatic Apobec-1, ApoB48,LDLR and LRP protein expression incomparison Compared with the sham operation group, nephropathy group showed that the expression of LDLR was down-regulated (P<0.05), the expression of LRP was up-regulated (P<0.05), while the expression of Apobec-1 and ApoB48 had nothing change. Compared with nephropathy group and the sham operation group, Apobec-1 treatment group showed that the expression of LDLR was down-regulated (P<0.05,P<0.01), while the expression of Apobec-1,ApoB48 and LRP was up-regulated (P<0.01).Conclusion1. When liver acquired expression of Apobec-1 in hyperlipidemia of nephrotic syndrome apobec-1 recombinant adenovirus, it play a certain lipid-lowering effect, and arrive in normal level.2. When nephropathy rabbits were infected by apobec-1 recombinant adenovirus, it make the expression of Apobec-1 in liver, then increase the synthesis of ApoB48-lipoprotein, and play a certain lipid-lowering effect.3. When liver acquired expression of apobec-1 in hyperlipidemia of nephrotic syndrome by apobec-1 recombinant adenovirus, it can up-regulation of LRP, accelerate the elimination of apoB48-lipoproteins, and play a certain lipid-lowering effect.