Comparison of effects of vanadium absorbed by Coprinus comatus with those of inorganic vanadium on bone in streptozotocin-diabetic rats.

The purpose of this study was to compare the effect of vanadium absorbed by Coprinus comatus (VACC) with inorganic vanadium (vanadium nitrate, IV) in preventing diabetes-related osteopenia in streptozotocin-diabetic rats. Sixty Wistar female rats used were divided into four groups: (1) normal rats (control), (2) diabetic rats, (3) diabetic rats treated with VACC, and (4) diabetic rats treated with vanadium nitrate. A standardized type 1-like diabetes model was induced by injection of streptozotocin. After the rats were treated orally with VACC and IV respectively, plasma glucose, body weights, micro-CT, biomechanical testing, and histomorphometry were examined. In addition, bone samples were obtained to evaluate the content of mineral substances in bones. Treatments were performed over a 12-week period. Both VACC and IV have a positive effect on plasma glucose and body weights of STZ-induced diabetic rats. However, treatment with IV only caused a 39.6 % decrease in glucose levels and a 14.6 % increase in body weights, whereas VACC decreased plasma glucose and increased body weights by up to 52.2 and 24.5 %, respectively. At the same time, VACC significantly improved trabecular microstructure and mechanical strength, while IV did not exhibit desirable such effects. Also, bone Ca and bone P were not significantly increased by IV. These results indicated that both VACC and IV have hypoglycemic activity on diabetic rats, while IV did not improve bone properties. In conclusion, this study suggests that VACC improves diabetes-related bone dysfunction, primarily by improving the diabetic states.