| Objectives①To observe the morphologic change of the kidney tissue of the high-fat-diet rats under light microscope;②To observe the cell apoptosis in the kidney tissue of the high-fat-diet rats;③To observe the change of expression of Bcl-2 and Bax in kidney tissue of the high-fat-diet rats;④To analyze the influence of high-fat diet on kidney tissue of rats by morphometrics.Methods 20 SD male mice were divided into two groups: ten to high-fat-diet group and ten to the controlled group. The controlled group were fed on complete feed in the room temperature and steady humidity, while the high-fat-diet group were given high-fat food (which was made up of 2% cholesterol, 10% lard and 88% basic feeding stuff). After 6 weeks their blood serum was tested, in which the kidney were taken to :①Do Hematoxylin-Eosin(HE) staining;②Measure the apoptosis cells in the kidney tissue by teminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method;③Do immunohistochemical staining;④Calculate the Bcl-2 mesn optical density(MOD), Bax MOD, average diameter of renal corpuscle, average perimeter of renal corpuscle,average diameter of proximal convoluted tubules, average diameter of distal convoluted tubules by computer picture analysis software.Results①The blood serum triglyceride (TG), of high-fat-diet group was evidently higher than the controlled group((0.74±0.09 vs 0.49±0.05); The blood serum total cholesterol (TC) of high-fat-diet group was evidently higher than the controlled group(1.19±0.18 vs 0.92±0.19); while the high density lipoprotein cholesterol(HDL-C) of high-fat diet group was evidently low compared with the controlled group and the difference was significant(P<0.05);②HE staining showed that the structure of kidney tissue was normal. Compared with it, the structure of kidney tissue of the high-fat-diet group had no evident pathological under the light microscope.③The result of the apoptosis test by TUNEL method suggested that there were apoptosis cells with brown nucleolus in both groups. Yet the controlled group had a few and a small amount of apoptosis cells could be seen in the glomerular,and more could be found in the tubular in the high-fat-diet group.Besides, there were also some in renal interstitium.The number of apoptosis cells of controlled group was 3.57±1.38/HP,while that of the high-fat-diet group was 15.45±5.07/HP. The difference was significant(P﹤0.05).④The result of immunohistochemisty staining showed that Bcl-2 and Bax were expressed in both groups, positive reactants were located in cytoplasm and were brown grains. Bax was located mainly in the renal tubular epithelial cells,and a small amount could also be found in glomerular. And Bcl-2 was mainly located in the renal tubular epithelial cells,and a small amount could also be found in glomerular.The number of Bcl-2MOD in the kidney tissue of high-fat-diet group was 0.2450±0.0216, and Bax MOD was 0.2763±0.0912.Compared to Bcl-2 MOD(0.2941±0.0204)and Bax(0.1506±0.3334)MOD of the controlled group, the difference was significant.(P﹤0.05)⑤The morphometric analysis of the kidney tissue suggested that the average diameter of renal corpuscle of high-fat-diet was evidently smaller than that of the controlled group ( 229.5126±37.3912 vs 262.4389±38.5034),the average perimeter of renal corpuscle of the high-fat-diet was evidently smaller than that of the controlled group ( 830.0191±136.0398 vs 974.8371±128.1884),the average diameter of proximal convoluted tubules of the high-fat-diet group was evidently smaller than that of the controlled group, (95.1354±16.1624 vs 102.2602±16.0461),and the average diameter of distal convoluted tubules of high-fat-diet group was evidently smaller than the controlled group. (78.6235±15.6967 vs 89.8674±21.7171). The difference was distinct (P<0.05).Conclusion①The amount of apoptosis in the kidney tissue of the a high-fat-diet rats increased;②The expression of Bcl-2 in the kidney tissue of high-fat-diet rats was weakened while the expression of Bax was reinforced.③The average diameter and the average perimeter of renal corpuscle of kidney tissue decreased.The average diameter of proximal convoluted tubules and distal convoluted tubules of the high-fat-diet rats decreased;④Apoptosis was probably one of the mechanism of toxic injury to the kidney induced by lipid.What's more, the expression of Bcl-2, Bax and Bcl-2/Bax influenced the happening of apoptosis. |
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