Modulation by NADPH oxidase of the chronic cardiovascular and autonomic interaction between cyclosporine and NSAIDs in female rats
Cyclosporine (CSA) and nonsteroidal antiinflammatory drugs (NSAIDs) are used together to manage arthritic disorders with an immune component. Previous reports showed contrasting effects for NSAIDs on CSA nephrotoxicity and acute elevations in blood pressure. Both effects were ameliorated or exaggerated after selective cyclooxygenase-2 (COX2) and nonselective COX inhibition, respectively. Here we investigated: (i) the interaction of CSA with NSAIDs possessing variable COX1/COX2 selectivities on hemodynamic, left ventricular (LV) and cardiac autonomic and histologic profiles, and (ii) role of NADPH-oxidase (NOX)/Rho-kinase (ROCK) pathway in the interaction. Female rats were pre-instrumented with femoral catheters and treated for 10 days with CSA (25 mg/kg/day), diclofenac (nonselective NSAIDs, 1 mg/kg/day), celecoxib (COX2 inhibitor, 10 mg/kg/day), or their combinations. CSA-mediated hypertension was maintained upon co-administration of either NSAID whereas the concomitant reductions in time- and frequency-domain indices of heart rate variability (HRV) were accentuated in presence of diclofenac but not celecoxib. The isovolumic relaxation time (Tau), a measure of diastolic function, was reduced by all regimens whereas LV contractility (dP/dtmax) remained unaffected. The CSA/diclofenac regimen, but not individual treatments, increased cardiac NOX2 expression and caused more cardiac structural damage. The inhibition of NOX by diphenyleneiodonium reversed CSA/diclofenac-evoked increases in MAP, decreases in HRV and Tau, cardiac structural damage, and increased NOX2 expression. No such effects were observed after ROCK inhibition by fasudil, despite concomitant decreases in NOX2 expression. In conclusion, CSA/diclofenac-treated female rats exhibit exacerbated hemodynamic, autonomic, LV, and histopathologic disturbances via ROCK-independent NOX2 upregulation.