Effect of indomethacin on bone remodelling in rabbit ear chambers

The effect of indomethacin medication on bone tissue resorption and formation was assessed by qualitative and quantitative microscopy in vivo in 18 rabbit ear chambers in 12 rabbits. Five bone tissue experiments were carried out during half a year using the rabbits as their own controls. One daily oral indomethacin dosage of 10 mg/kg body weight given for 3 weeks inhibited resorption of bone autografts in this type of vital chamber and thus inhibited disordered osteoclastic activity. The effect of indomethacin on ordered osteoclastic activity was not quantitated, nor was its effect on parallel-fibred bone tissue formation assessed. The same dosage of indomethacin clearly retarded woven-fibred bone tissue formation (by 1 week) as compared to control experiments, in which the chambers were used as their own controls. It is concluded that indomethacin treatment of patients liable to develop para-articular ossifications therefore seems rational. Indomethacin and drug-induced arthropathy of the hip-joint is discussed in relation to the presented results. A final appraisal of the role of indomethacin in this complex process must await additional material.