Effect of indomethacin on regulation of juxta-articular bone blood-flow during joint tamponade. An experimental study in puppies

Prostaglandins are vasoactive substances which are assumed to play a major role in bone metabolism and bone repair. The purpose of the present study was to investigate the effect of indomethacin on the control of epiphyseal bone blood-flow. By means of simultaneous intra-osseous pressure (IOP) and regional blood flow (RBF) measurements in the distal femoral epiphysis (DFE), aspects of vascular control mechanisms in the distal femoral epiphysis were investigated during knee joint tamponade (50% of mean arterial pressure) before and after administration of indomethacin 7.5 mg/kg. Six dogs aged 3-4 months were investigated in fentanyl anaesthesia. Knee joint tamponade resulted in a significant increase in IOP and calculated venous resistance in the DFE, while no significant changes in regional blood-flow or arterial resistance were encountered. Administration of indomethacin did not affect this reaction. The results suggests that indomethacin 7.5 mg/kg does not influence the regulation of epiphyseal blood-flow during elevation of joint pressure indicating that prostaglandins play only a minor or no role in this regulation.