宫内发育迟缓大鼠老年期血脂水平、肝脂肪含量及脂肪特异性蛋白27表达变化

Blood lipid level,liver fat content and expression changes of fat-specific protein 27 in aged intrauterine growth restriction rats

目的观察宫内发育迟缓(IUGR)大鼠老年期血脂水平、肝脂肪含量及脂肪特异性蛋白27(Fsp27)表达变化。方法取IUGR和适于胎龄(AGA)大鼠各8只,分别设为IUGR组和AGA组。两组大鼠予标准配方饲料喂养至12月龄时处死,心腔穿刺采血,用酶法检测血浆LDL-C、TC、游离脂肪酸(FFA)、HDL-C及TG;取肝组织行HE染色,光镜下观察两组大鼠肝脏形态学改变;采用酶法测定肝脏TG和TC;采用逆转录聚合酶链反应法检测肝组织Fsp27 mRNA,采用Western blotting法检测肝组织Fsp27蛋白。结果 IUGR组、AGA组血浆TC分别为(0.57±0.14)、(0.32±0.15)mmol/gprot,LDL-C分别为(7.16±1.08)、(5.32±0.88)mmol/L,HDL-C分别为(3.33±0.54)、(4.47±0.71)mmol/L,TG分别为(2.21±0.23)、(1.66±0.15)mmol/L,FFA分别为(1.46±0.25)、(1.17±0.21)mmol/L,两组比较,P均<0.01。AGA组大鼠肝细胞形态、大小正常,胞质呈均匀红染,细胞内少见脂滴及空泡,而IUGR组大鼠肝细胞胞质内出现大量大小不等的脂滴及空泡。IUGR组、AGA组大鼠肝组织TC分别为(1.41±0.37)、(1.03±0.30)mmol/gprot,TG分别为(2.38±0.39)、(1.81±0.54)mmol/L,两组比较,P均<0.05。IUGR组、AGA组肝组织Fsp27 mRNA相对表达量分别为4.35±1.12、2.37±0.75,Fsp27蛋白相对表达量分别为1.19±0.23、0.69±0.16,两组比较,P均<0.01。结论与AGA大鼠相比,IUGR大鼠老年期血浆TC、LDL-C、TG、FFA水平高,血浆HDL-C水平低,肝组织脂肪含量高,这可能与肝组织Fsp27表达升高有关。

Objective To observe the blood lipid level,liver fat content and the expression changes of fat-specific protein 27（ Fsp27） in the aged intrauterine growth restriction（ IUGR） rats. Methods A total of 8 newborn IUGR rats（ IUGR group） and 8 newborn appropriate-for-gestational-age（ AGA） rats（ AGA group） were breastfed by their mothers and then were fed on normal diet after weaning until the age of 12 months. The morphology of hepatocyte was observed under optical microscopes. We detected the levels of LDL-C,TC,FFA,HDL-C and TG in the plasma as well as TC and TG in the liver tissues by enzymatic method. We also detected the mRNA and protein expression of Fsp27 in the liver tissues by RT-PCR and Western-blotting,respectively. Results In the plasma of IUGR group and AGA group,the serum TC was respectively（ 0. 57 ± 0. 14） and（ 0. 32 ± 0. 15） mmol/gprot,LDL-C was respectively（ 7. 16 ± 1. 08） and（ 5. 32 ± 0. 88）mmol/L,HDL-C was respectively（ 3. 33 ± 0. 54） and（ 4. 47 ± 0. 71） mmol/L,TG was respectively（ 2. 21 ± 0. 23） and（ 1. 66 ± 0. 15） mmol/L,FFA was respectively（ 1. 46 ± 0. 25） and（ 1. 17 ± 0. 21） mmol/L,and significant difference was found between these two groups（ all P〈0. 01）. At the age of 12 months,the morphology and size of hepatocyte was normal and the cytoplasm was homogeneous in AGA rats. The hepatocyte cytoplasm of AGA rats had rare lipid droplets and vacuoles,while the IUGR rats had large unequal-sized lipid drops in cytoplasm. In the liver tissues of IUGR group and AGA group,TC was respectively（ 1. 41 ± 0. 37） and（ 1. 03 ± 0. 30） mmol/gprot,TG was respectively 2. 38 ± 0. 39 and1. 81 ± 0. 54,and significant difference was found between these two groups（ all P〈0. 05）. In addition,the mRNA expression of Fsp27（ 4. 35 ± 1. 12） in the IUGR group was significantly higher than that（ 2. 37 ± 0. 75） of the AGA group as well as the protein expression [（ 1. 19 ± 0. 23） vs（ 0. 69± 0. 16） ]（ all P〈0. 01）. Conclusion Compared with the AGA rats,the aged IUGR rats have higher levels of TC,LDL-C,TG and FFA in blood lipids,lower level of HDL-C and higher liver fat content,which may be associated with the higher expression of Fsp27 in liver tissues.