[Bone histomorphometric osteopenia induced by ovariectomy or diabetes mellitus in rat].

To discover the risk factors associated with the occurrence of osteoporosis, the development of osteopenia and bone remodeling through bone histomorphometry on the proximal tibia was observed in female Wistar rats subjected to either ovariectomy (OVX) and/or diabetes mellitus. Diabetic rats were obtained by the intra-abdominal administration of 30 mg/kg streptozotocin (STZ). Single-loaded groups were the OVX group and the STZ group, while the combined group was the OVX+STZ group. Each group was further divided into two subgroups according to the experimental periods of 3 months and of 6 months. Bone histomorphometry was performed on the tibial metaphysis. The results showed a significant bone volume decrease in both the single-loaded groups at 3 months. The decrease was greater in the STZ group than in the OVX group. In the single-loaded groups at 6 months, there were even greater decrease. The combined group showed a smaller bone volume decrease after 3 months than the STZ group and the OVX group. However, at 6 months, the combined group showed a bone volume decrease significantly greater than the single-loaded OVX group. The bone-formation related parameters (osteoid surface, osteoid volume, mineralizing surface, mineral apposition rate, and bone formation rate parameters) of the STZ group and the OVX+STZ combined group at 3 months showed a considerable decrease in bone volume; no double labeling surfaces were observed in the 6-month OVX+STZ group; there was also a decrease in the osteocalcin level.(ABSTRACT TRUNCATED AT 250 WORDS)