肾病综合征兔肝脏获得性表达apobec-1降脂效应及可能机制

The lipid - lowering effect and possible mechanism of apobec - 1 in nephrotic syndrome rabbits

目的观察肝脏获得性表达apobec-1对肾病综合征（NS）兔血脂代谢及肝脏低密度脂蛋白受体（LDLR）、低密度脂蛋白受体相关蛋白（LRP）表达的影响，探讨Ns兔apobec-1降脂效应及其可能机制。方法30只健康雄性普通级新西兰兔随机分为假手术组、Ns组、apobec-1治疗组，每组10只。Ns组、apobec-1治疗组适应性喂养1周后行左肾切除术，术后1周耳缘静脉注射阿霉素（4mg／kg）构建Ns模型；术后11周apobec-1治疗组耳缘静脉注射apobec-1重组腺病毒（1×10^13病毒颗粒／kg）。术后12周处死所有兔，并摘除右侧肾脏和肝脏，留取血液及24h尿液，检测24h尿蛋白（24UPr）、清蛋白（A1b）、尿素氮（BUN）、肌酐（Cr）、血脂等指标，HE染色观察肾脏病理，Western blot检测肝脏LDLR、LRP蛋白表达水平。结果1．假手术组、Ns组及apobec．1治疗组3组之间比较显示24UPr（F=42．778，P=0．000）、Alb（F=3．819，P=0．034）、BUN（F=6．562，P=0．005）、Cr（F=16．076，P=0．000）、总胆固醇（TC，F=17．531，P=0．000）、三酰甘油（TG，F=6．192，P=0．006）、极低密度脂蛋白（VLDL—C，F=6．192，P=0．006）、低密度脂蛋白（LDL．C，F=34．924，P=0．000）、载脂蛋白B100（ApoB100，F=5．180，P=0．012）、载脂蛋白B48（ApoB48，F=6．161，P=0．006）差异均有统计学意义。2．与假手术组比较，Ns组24UPr、BUN、Cr、TC、TG、VLDL—C、LDL—C、ApoB100明显升高，而Alb明显降低，差异均有统计学意义（P均〈0．05）。3．与Ns组比较，apobec-1治疗组Tc、TG、VLDL—C、LDL．C、ApoB100、ApoB48明显降低，差异均有统计学意义（P均〈0．05）。4．与假手术组比较，apobec．1治疗组24UPr、BUN、Cr明显升高，而Alb、ApoB48明显降低，差异均有统计学意义（P均〈0．05）。5．Western blot结果显示3组之间LRP（F=44．180，P=0．000）、LDLR（F=63．141，P=0．000）差异具有统计学意义，与假手术组、Ns组比较，apobec．1治疗组肝脏LDLR蛋白表达明显下调（P〈0．01、0．05）；LRP蛋白表达明显上调（P均〈0．01）。结论NS肝脏获得性表达apobec-1可通过上调LRP，加速ApoB48-脂蛋白的清除，进而起到一定降脂效应。

Objective To observe the effect of liver acquired expression of apobec - 1 on blood lipid metabolism, hepatic low density lipoprotein receptor （LDLR）, and hepatic low density lipoprotein receptor related protein （LRP） in nephrotic syndrome（NS） rabbits and to explore the lipid - lowering effect and possible mechanism. Methods Thirty healthy ordinary level male new Zealand rabbits were randomly divided into 3 groups：sham operation group （ n = 10） , NS group（ n = 10） , and apobec - 1 treatment group（ n = 10）. Adaptive feeding was given for 1 week, then NS group and apobec - 1 treatment group underwent left nephrectomy, and 1 week later, adriamycin （4 mg/kg） was used to construct the NS model by way of ear vein injection. In the 11 th week after operation, apobec - 1 recombinant adenovirus （ 1 ~ 1013 virus/kg） was injected through ear vein in apobec - 1 treatment group. The 12th week after operation, all rab- bits were sacrificed. Right kidney, liver, blood and 24 hour urine were collected. In 3 groups, 24 hour urinary protein （24UPr） , albumin （Alb） , blood urea nitrogen （BUN） , creatinine （Cr） , blood lipid were detected. Renal pathology was observed by means of HE staining. Expressions of liver LDLR, LRP were observed by using Western blot. Results （ 1 ） There were significant differences among the 3 groups in 24UPr （ F = 42. 778, P = 0. 000） , Alb （ F = 3. 819, P = 0.034）,BUN （F=6.562,P=0.005）,Cr （F=16.076,P=0.000）,total cholesterol （TC） （F=17.531,P= 0. 000 ）, total triglyceride （TG） （ F = 6.192, P = 0.006 ）, very low density lipoprotein （ VLDL - C ） （ F = 6. 192, P = 0.006） ,low density lipoprotein （ LDL - C ） （ F = 34. 924, P = 0. 000 ） and apolipoprotein B100 （ApoB100） （ F = 5. 180,P =0. 012） and apolipoprotein 1348 （ApoB48） （F=6. 161 ,P =0. 006）. （2） Compared with the sham opera- tion group,NS group showed that 24UPr, BUN, Cr,TC,TG, VLDL- C, LDL- C, ApoB100 increased, but Alb decreased, and there was statistical significance （ all P 〈 0.05 ）. （ 3 ） Compared with NS group, apobec - 1 treatment group showed that TC, TG, VLDL - C, LDL - C, ApoB100, ApoB48 decreased, and there were statistical significances （ all P 〈 0.05）. （4） Compared with the sham operation group,apobec- 1 treatment group showed that 24UPr, BUN, Cr increased, but Alb, apolipoprotein 1348 （ ApoB48 ） decreased, there were statistical significances （ all P 〈 0.05 ）. （5） There were significant differences of hepatic protein expression among the 3 groups in LRP（ F = 44. 180, P = 0. 000）, LDLR （F = 63. 141, P = 0. 000）. Compared with the sham operation group and NS group, apobec - 1 treatment group showed that the expression of LRP was up - regulated （P 〈 0.01,0.05 ） , while the expression of LDLR was down - regulated （all P 〈 0.05 ）. Conclusions When liver acquired expression of apobec - 1 in NS, it could up - regulate LRP, accelerate the elimination of ApoiM8 - lipoproteins, and produce a certain lipid - lowering effect.