Abstract
Development and morphology of the epiphyses of the long bones were investigated in 93 adult rats of 7 different strains (BDIX/Han, BDE/Han, BN/Han, DA/Han, LEW/Han, AVN/IpcV/Wistar/Rehbrücke, Shoe: WIST) from the age of 14 weeks up to the age of 78 weeks. Strain-related differences were found in the development of the secondary centre of ossification, which was retarded in the BDIX/Han rats. Furthermore, closure of the growth plate started earlier in the BDIX/Han rats. In addition various regressive changes were detected in the growth plates of long bones of all rats, but not of the ribs. The frequency and extent of these changes varied between individuals and strains. Degeneration of the matrix and necrosis were already observed at 14 weeks of age.