To Study The The Damage Of Podocyte And Glomerulosclerosis Progressive Process In The Puromycin Nephritis Rat Model

Objective: To study the podocyte damage playing an impotant role in the glomerularsclerosis progressive process from clinical, pathological, and podocyte relative proteinsexpressions by using puromycin aminonucleoside nephropathy model (PAN).Mehtods: Male adult Sprague-Dawley (SD) rats, weight at200-250g were divided intotwo groups, control and PAN. PAN rats received a single intravenous injection via tail veinwith PAN at15mg/100g of body weight; and control rats was injected by equal amount of0.9%NS. The clinical and pathological parameters were analyzed at4and8days for acutelesions evaluation, and at4、14and20weeks for the chronic renal injuries evaluation.The ratswere executed at4weeks,14weeks and20weeks and kidneys were taken out and embeddedin paraffin for making the slices.The slices were stained using PAS andimmunohistochemistry methods, and Glomerular areas and Glomerulosclerosis index weremeasured and anlysized by using PAS staining iIn high magnification. Finaly, theexpression of nephrin and WT1were stained and anlysized by using immunohistochemistrystaining and semi-quantitative analysisResults:1. Urinary protein (UP) excretion in the PAN group increased significantly,peaking at8days, then decreased at4weeks; it’s however increased again significantly at14and20weeks. At the8days, serum total protein (TP) and Alb was significantly decreased,and TC and TG were significantly increased in PAN group. The glomerulosclerosis index(GSI) was6.21%,25.35%and30.49%respectively at4、14and20weeks in the PAN group.It is significantly high percentage than the control rat. The Scr was significantly increased in PAN group at20weeks. The systolic BP in PAN group was significantly high at4,14and20weeks.2.The mean size of glomerular area in PAN rats did not have significant changes at4weeks comparing with control rats；the mean size of GA in the PAN rats is significantlybigger than it in the control group at14weeks (They mean area:522.36±13.04μm2vs469.20±8.16μm2，P<0.01); but the Mean size of GA in the PAN rats is significantly smallerthan it in the control group at20weeks (They mean area:438.59±12.11μm2vs492.69±58.24μm2，P<0.001), there was the negative correlation between glomerular area (GA) andglomerulosclerosis index (GI) at20weeks, the r-value is-0.82.3. The expression of nephrin isslightly decreased in PAN group in4weeks, a partially decline and disappeard（Themeans:8.23±0.875vs10.23±1.256，P<0.001）; there is no expression of nephrin in segmentalsclerosis in14weeks（The means:7.58±0.712vs9.74±1.234，P<0.001）, and in the sclerosisglomerular in20weeks（The means:6.08±1.342vs7.88±0.924，P<0.001）, compared with thecontrol group showed significant differences.4. The expression of WT-1is no significantdifferences in4weeks, compared with the control（The means:10.11±1.557vs10.14±2.022，P>0.05）. The expression of WT-1in PAN group was decreased in14weeks （Themeans:6.8±1.887vs9.02±1.732, P<0.001）, was remarkably decreased more in20weeks（Themeans:4.43±1.007vs7.34±1.216，P<0.001）. The numbers of podocyte were decreased withabove time course.Conclusion：1. The PAN rats model is successfully built up: there is a typical nephroticsyndrome on the8days and a CKD process to the glomerulosclerosis from4weeks to14and20weeks;2. there is negative correlation between glomerulosclerosis index and glomerulararea in the chronic progressive process..3. The expressions of nephrin and WT-1are droppedaccording the time course, especially in20weeks. Both of them indicate the degree ofdamage of function and structure of podocytes and the number losing of podocyte. Therefore,the podocyte damage and number losing are relative to the glomerular sclerosis.