抄録
Vascular changes and growth retardation in the femurs of developing rabbits were observed to ascertain the effect of administration of steroids on bone. Forty female Japanese white rabbits, six weeks old at the start of the study, were used. The animals were divided into two groups: one of 25 animals that received a weekly dose of 2.5 mg/kg of methylprednisolone acetate, and a control group of 15 animals that received no drugs. Vascular changes were investigated by microangiography and histopathology at two-week intervals over a period from 2 to 12 weeks. Growth retardation was assessed by radiographs over the same period. The number of small vessels were counted using a microscope, and the percentage of marrow fat cell area was measuring using a transmission type digitalizer and an image analyzer. At Week 4, microangiography showed numerous small vessels in the steroid group, and marrow fat cell volume was significantly higher than that in the control group. At Week 12, microangiography revealed newly formed vessel caliber. The number of small vessels and the fat cell volume were normalized; however, histopathologically, there was no significant degeneration of vascular tissue. Throughout the study, the average length of femurs in the steroid group was signicantly less than that of animals in the control group. At Week 8 and Week 12, the average epiphyseal width of the steroid group in creased compared with that of the control group. In conclusion, blood supply was impaired in the femurs of rabbits in the steroid group, which was followed by subsequent normalization. This study implies a possible relationship between growth retardation and change in blood supply in rabbits which are administered a steroid.
