In order to evaluate a possible role of thromboxane A2 (TxA2) in the pathophysiology of chronic glomerular disease, we studied the effect of a 12-wk combined treatment with the thromboxane receptor blocker Daltroban (D) and the thromboxane synthesis inhibitor UK 38485 (UK) on glomerular function and morphology in a rat model of chronic progressive glomerular injury. The glomerular lesion was induced in unilaterally nephrectomized rats by the repeated i.v. injection of an antibody directed against mesangial cells. Control rats were uninephrectomized. Three months after the first antibody injection before D and UK treatment, albuminuria (35.8 +/- 3.6 mg/24 h) and glomerular TxB2 formation (146 +/- 20 pg/mg of protein/min) were significantly higher compared with control values (albuminuria, 14.3 +/- 3.5 mg/24 h; TxB2, 59 +/- 16 pg/mg/min). Six months after antibody, albuminuria in nephritic rats had increased to 135 +/- 17 mg/24 h. In nephritic rats treated with D plus UK, albuminuria (44 +/- 12 mg/24 h), however, was significantly (P less than 0.001) inhibited. Quantitative morphological analysis (glomerular damage index) 6 months after antibody revealed significantly (P less than 0.001) increased glomerular lesions in nephritic rats (0.353 +/- 0.095) compared with that in uninephrectomized controls (0.045 +/- 0.014). The treatment of rats with D and UK significantly (P less than 0.001) reduced the glomerular damage index (0.101 +/- 0.004) in nephritic rats. D plus UK treatment reduced glomerular TxB2 formation but increased prostaglandin E2 and 6-keto prostaglandin F1 alpha release by isolated glomeruli. This study demonstrates that interventional treatment with D and UK ameliorates albuminuria and glomerular morphological lesions in a rat model of immunologically induced progressive glomerular injury.