Effect Of Atorvastatin On Expression Of COX-2 And CTGF Kidney Of Rats With Unilateral Ureteral Obstruction

Objective:The Rats model of renal interstitial fibrosis was established by unilateral ureteral obstruction(UUO) in this research . Atorvastatin and Celecoxib were given in differential group.The morphological changes of kidney tissue were observed,and expression and variety of the COX-2 CTGF and Col-Ⅰin renal were observed and discussed by immunohistochemistry . Investigate the mechanism of renal interstitial fibrosis of unilateral ureteral obstruction in rats and the effects of atorvastatin on it. This research perhaps explore a experimental theory for preventing chronic kidney disease progress.Methods:60 health male SD rats weighing 180g+20g were numbered and then randomly divided into 4 groups:sham-operated group(A), UUO group(B),UUO with treated Atorvastatin group(C). UUO with treated Celecoxib group(D). All of the rats were allowed free access to food and water 5 days up to 12 hours befor establishing the unilateral ureteral obstructive rat model.All of the rats were anesthetized with 10% Chloral Hydrate(0.9ml+0.1ml)by intraperitoneal injections.A left back incision was made after disinfection and draw off the muscular tissue to expose the left kidney,the left ureter was ligated by 4.0 silk at two points and cut between the ligatures to prevent retrograde urinary infection after being searched along the inferior pole of left kidney.Sham-operated rats only free the ureter,but not ligated From one day before surgery until the day killed, Atorvastatin(10mg·Kg^-1·d^-1,Qd)and Celecoxib(10mg·Kg^-1·d^-1,Qd) were administrated respectively to group C and D,and the same volume of physiological saline was administrated as control.The obstructed left kidneys were harvested after UUO 3,7,and 14 day (n=5 at ecah time point ) and fixed in 4% phosphate-buffered paraformaldehyde , dehydrated by alcohol, transparented by xylene, and embedded by paraffin.Tissue sections at 5μm were obtained.Under the light microscope, pathological changes were observed by using Masson stain to calculate the pathological area of the obstruced kidney.The changes of COX-2,CTGF and Col-Ⅰand their expression in kidney were analyzed by immunohistochemical method.The results of experiment were analyzed semi-quantitatively by the pathological image analysis system. The datas were analyzed by SPSS13.0 statistics software, Pvalue<0.05 was considered to have statistical significance.Results:Gross observation: The shape of kidneys in group A were normal . The obstruction kidneys become bigger in the other groups since the third day after surgery,and the obstruction kidney was bigger than the other one in the same rat.The bigger kidneys were ash red with white,and kidney hydrops appeareded,renal cortex became thinner, renal pelvis expanded, renal calyx and Intra-operative papillary were coppressed.The lesion change were behavier as time went on. the group B were behavier than group C and group D.The renal patholgical change:Masson:The structure of glomeruli and interstitial tubule in kidney of group A were not abnormal, The renal interstitium around tubule were narrow.In UUO group,the renal tubule became expanded from 3 day after surgery.the areas of interstitium and Collagen fibers increased, the above of all pathological changes were more and more seriouos with time of obstruction. Immunohistological staining, the expression of COX-2 (was granular) was in the cytoplasm of tubule epithelial cells and interstitial cells, The percentage of COX-2-positive area in interstitium at day3,7,14 after UUO in group A was (1.33±0.26)%,(2.71±0.29)%,(2.92±0.86)% , and the numbers in group B,C,D respectively were (4.44±0.51)%,(5.89±0.98)%,(22.40±2.50)%,(2.91±0.14)%,(4.54±0.31)%,(9.94±0.78)%,(3.29±0.52)%,(4.50±1.30)%,(12.31±1.46)%. the area of CTGF expression was the same of COX-2, and it was uneven granular. The serious area confluenced lamellar domain. The percentage of CTGF-positive area in interstitium at day3,7,14 after UUO in group A was(1.41±0.10)%,(1.77±0.22)%,(2.17±0.18)%,and the numbers in group B,C,D respectively were(2.80±0.34)%,(4.47±1.78)%,(16.62±2.05)%,(2.46±0.30)%,(3.29± 0.38)%,(5.24±0.67)%,(2.44±0.77)%,(3.40±0.78)%,(7.46±5.72)%. Col-1, seemed linear, expressed renal interstitial,and was also observed in cytoplasm of tubule epithelial cells.the percentage of Col-1-positive area in interstitium at day3,7,14 after UUO in group A was(2.07±0.25)%,(2.46±0.32)%,(2.89±0.89)%, and the numbers in group B,C,D respectively were(3.79±0.27)%,(6.28±0.89)%,(20.46±2.98)%, (3.17±0.19)%,( 4.46±0.14)%,(10.85±0.82)%,(3.26±0.12)%,(4.59±0.14)%,(12.05±1.87)%.Compared these three factors in experiment, It was significant difference between any two of the four groups(P<0.05),only rats between groupC and D revealed constant levels(P>0.05). furthermore, It was significant difference between any two time points except between day 3 and 7 after UUO.Conclusions:(1)The expression of COX-2,CTGF and Col-1 were up-regul in obstruction kidneys in UUO,and were more and more as time went on after UUO. (2).Both Atorvastatin and Celecoxib can make the expression of COX-2,CTGF and Col-1 down-regulation in kidney of UUO rats,postpone fibrosis of renal interstitium.Moreover.Maybe Atorvastatin inhibited CTGF because of down -regulation of COX-2.