A histopathological study on the femoral head necrosis in spontaneously hypertensive rats (SHR)

: The histopathological study was conducted in the femoral head of spontaneously hypertensive rats (SHR), which had frequently manifested osteonecrosis and a delay in the ossification at the femoral epiphysis. In order to elucidate the course of necrosis and its repair process, the bone dynamic of the femoral head was investigated with bone fluorochrome labelling technique. Femoral epiphyses in the SHR were classified into five groups, according to their histopathological changes in relation to osteonecrosis, its repair process and the delay in ossification. Changes in the growing rate of the growth plate at the femoral head and neck were measured quantitatively. As a result, the articular cartilage remained viable and overgrowing, while the epiphyseal plates were affected by the necrosis and there was early physeal maturation occurred. It is concluded that SHR appear to be a useful experimental model for Perthes' disease.