['The current study was done to determine whether atorvastatin, the HMGCoA (3-hydroxy-3-methylglutaryl CoA) reductase inhibitor, could decrease renal transforming growth factor-beta (TGF-beta) levels in unilateral ureteral obstruction (UUO) and concomitantly affect renal tissue damage in UUO.', 'Atorvastatin (20 mg/kg) was administered to rats 1 day prior to UUO and every day thereafter. Kidneys were harvested at day 14 after UUO. Tissue TGF-beta was measured by bioassay using mink lung epithelial cells. Renal tubular proliferation and apoptosis were detected by immunostaining proliferating cell nuclear antigen and polyclonal antisingle strand DNA antibody, respectively. Fibrosis was assessed by measuring collagen deposition with trichrome stained slides. Interstitial leukocyte was detected by immunostaining CD45.', 'TGF-beta bioassay showed that the obstructed kidney in the control group contained significantly higher TGF-beta than the unobstructed kidney in the control group (mean +/- SD 79.1 +/- 48.5 vs 28.7 +/- 13.7 pg/mg tissue) and atorvastatin significantly decrease tissue TGF-beta in the obstructed kidney (53.4 +/- 37.0 pg/mg tissue). Immunostaining polyclonal antisingle strand DNA antibody demonstrated that the obstructed kidney in the control group has significantly more tubular apoptosis than the unobstructed counterpart (4.8 +/- 2.8 vs 2.1 +/- 1.2 nuclei per high power field) and atorvastatin significantly decreased renal tubular apoptosis in the obstructed kidney (1.1 +/- 0.7 nuclei per high power field). In addition, immunostaining proliferating cell nuclear antigen showed that the obstructed kidney in the atorvastatin group had significantly more renal tubular proliferation than the obstructed kidney in the control group (48.7 +/- 20.8 vs 17.3 +/- 10.6 per high power field). Control obstructed kidney showed significantly more fibrosis, which was also blunted by atorvastatin.'] Does atorvastatin ameliorate renal tissue damage in unilateral ureteral obstruction?