Influence of genetic background and gender on hypertension and renal failure in COX-2-deficient mice

The present study was undertaken to determine whether the severity of renal failure or hypertension in homozygous cyclooxygenase (COX)-2-deficient (COX-2−/−) mice affected by genetic background or gender. COX-2 deletion was introduced into three congenic genetic backgrounds, 129/Sv (129/COX-2−/−), C57/BL6 (C57/COX-2−/−), and BALB/c (BALB/COX-2−/−), by backcrossing the original mixed-background knockout mice with the respective inbred strains for 9 or 10 generations. Evaluation of the severity of hypertension and renal failure was performed in knockout and wild-type mice at the age of 2.5–3.5 mo. Blood pressure measured by tail-cuff plethysmography was significantly elevated in the male 129/COX-2−/− mice (165.8 ± 9.2 vs. 116 ± 5.1 mmHg, P < 0.05), and to a much lesser extent in the female 129/COX-2−/− mice (127.4 ± 3.3 vs. 102.4 ± 3.3), whereas it was unchanged in the C57- or BALB/COX-2−/− mice regardless of gender. Urinary excretion of albumin, determined by EIA, was remarkably increased in the 129/COX-2−...