Résumé
Objective To investigate the effects of selective cyclooxygenase 2 inhibitor on the hyperplasia of parathyroid glands from uremic rats. Methods Sixty-five 5/6-nephrectomized (Nx) and fifteen sham operated rats were assigned to 4 groups: (1)Sham group (n=14):shamoperated +normal phosphate diet (P 0.8％,Ca 1.2％)； (2) Nx-HP group (n=17):Nx+high phosphate(HP) diet (P 1.2％,Ca 1.2％)； (3)Prophylactic COX2 inhibition group (Prey group,n=18):Nx+HP+celecoxib 100 mg· kg-1·d-1 for 3 months； (4)Therapeutic group (Ther group,n=18):Nx+HP+celecoxib 100 mg·kg-1·d-1 starting at the second month of the 5/6 nephrectomy.At the end of 3 month,blood,urine and parathyroid samples were collected.The expressions of COX2 and PCNA were determined by immunohistochemistry,Western blotting and real-time PCR. Results All of the Nx rats fed with high phosphate diet for 3 months manifested progressively increasing serum creatinine,serum iPTH as well as augmentation of parathyroid gland volume,suggesting that secondary parathyroid hyperplasia animal model was established successfully.Celecoxib significantly decreased serum iPTH levels [Sham (34.77±0.83),Nx-HP(100.73±4.35),Prey (87.36±2.18),Ther (87.47±1.76) ng/L,P＜0.05],the size of the parathyroid glands in Nx rats [Sham (0.461±0.089),Nx-HP (2.436±0.372),Prey (0.987±0.254),Ther (1.27±0.305) mm2/kg,P＜0.05] and PCNA expression in PG determined by Western blotting (decreased to 52.91％ in Prev group and 34.68％ in Ther group respectively,P＜0.05).No significant difference was observed between the two COX2 inhibition groups.The levels of COX2 expression in parathyroid gland were greatly increased in three Nx groups compared with that in sham group (2.47-fold in Nx-HP,2.34-fold in Prey group,3.04-fold in Ther group,P＜0.05).COX2 inhibitor had no effects on COX2 expression in PGs.Real-time PCR analysis demonstrated the same trends of mRNA expression of COX2 and PCNA in PGs of rats. Conclusion Selective inhibition of COX2 may help to suppress the hyperplasia of parathyroid glands in uremic rats.