The Expression And Significance Of COX-2 In Macula Densa And Podocyte Of ADPKD

Objective Autosomal dominant Polycystic kidney disease (ADPKD) is one of themost common inherited renal diseases. The incidence is 1:400～1:1,000. It causes 1/10 of all renal failure. Polycystic kidney disease progresses slowly but persistently, and Eventual end-stage renal failure is common. The aim of the present study is to determine the expression of cyclooxygenase-2 (COX-2) in macula densas and podocytes of ADPKD renal tissues, and to research the function of COX-2 in the pathogenesy and progress of ADPKD.Methods Cases were from hospital patients in urinary surgery of ShanDongProvincal from 2006 to2007. 38 samples of patients removed in unroof depressing operation were chosen as cases of experiment group, 22 cases were male, 16 cases were female ,the age were from 35-57, and the mean age was 48. 12 cases of normal renal tissues were chosen as control group.(1) The expression of HIF-1αwas assayed by means of immunohistochemical technique of SABC method. According to the different staining levels, expressions were scored positive, weakly positive and negative. Statistical method was performed to analyze the difference of COX-2 expression between normal renal tissues and Polycystic kidney tissues.(2) All the blood pressure of ADPKD patients were recorded and divided into 2 BP groups: A (systolic pressure 110～159 mmHg or diastolic pressure75～99 mmHg) ,B(systolic pressure≧160 mmHg or diastolic pressure≧ 100 mmHg) . Statistical method was performed to analyze the dependablity between BP and the levels of COX-2 in macula densa.(3) All the glomerular filtration rate of operative side kidney were recorded and divided into 2 GFR groups: A (50ml/min > GFR≧25ml/min) ,B (25ml/min > GFR > 10ml/min). Statistical method was performed to analyze the dependablity between GFR and the levels of COX-2 in podocyte.Results (1) The total positive expressive rate of COX-2 in the macula densa ofnomal kidney tissues was 50%, expression of COX-2 was much higher in the macula densa of human elderly(P < 0.05). The total positive expressive rate of COX-2 in the macula densa of Polycystic kidney tissues was 92.1%, meanwhile, was 100% in podocyte. COX-2 levels in macula densas of PK were higher than those in macula densas of NK(P < 0.05), and the expression of COX-2 in podocyte of PK was much higher than that in podocyte of NK(P < 0.01).(2) In BP groups A and B ,the rates of weakly positive expression were 45.0% and 22.2% respectively, with positive expression were 40.0% and 77.8% respectively. The levels of COX-2 significantly increased with the increase of BP (P < 0.05).(3) In GFR groups A and B , the total positive expression rate of COX-2 in podocyte of PK was 100%, the rates of weakly positive expression were 52.9% and 28.6% respectively, with positive expression were 47.1% and 71.4% respectively. The levels of COX02 significantly increased with the decrease of GFR (P < 0.05).Conclusion (1) The expression of COX-2 in macula densa of NK tissues was in anage-dependent feature, COX-2 was hardly detectable in podocyte of NK tissues by immunohistochemistry staining.(2) In macula densas and podocytes of PK tissues, the expression of COX-2 was significantly increased. There was no evidence that the expression of COX-2 in macula densas of PK tissues was age-dependent.(3) The levels of COX-2 in macula densa show a positive correlation with blood pressure of ADPKD patients. The expression of COX-2 in podocyte show a negative relationship with GFR of operative side kidney. Accordingly, COX-2 might play an important role in the pathogenesy of ADPKD.