Objective To study the difference in the bone mass and the levels of bone turnover markers and estrogen in the prednisolone- and dexamethasone-induced osteoporosis. Methods Forty-six 3-month-old female SD rats were randomly divided to 4 groups, baseline group (BL group, 6 rats), age-matched control group (AM group, 14 rats), prednisolone-treated group (PRE group, 14 rats), and dexamethasone-treated group (DXM group, 14 rats). Rats in BL group were euthanized at the beginning of the experiment. Rats in PRE group and DXM group were injected with PRE 5mg/kg per day and DXM 1mg/kg twice per week, respectively, for 3 months. Rats in AM, PRE, and DXM groups were euthanized in 1 month (M1), 2 months (M2), and 3 months (M3) after the treatment. The uterus and adrenal were collected for weight calculation. Serum estrogen, PINP, and β-CTX were examined. Bone mineral density (BMD) of the lumbar 1-3 were isolated and examined. Results BMD of rats at each time point in PRE (0.183±0.027, 0.230±0.005, 0.259±0.014 g/cm2) and DXM (0.191±0.010, 0.208±0.012, 0.200±0.004 g/cm2) was lower than that of rats in AM (0.251±0.014、0.275±0.009、0.281±0.008 g/cm2, P<0.05), The decrease was more notably in DXM rats (P<0.01). Moreover, BMD in DXM rats decreased significantly compared with PRE rats at M2 and M3 (M2, P<0.05; M3, P<0.01). Estrogen level in PRE rats (36.54±20.40 μg/L) was lower than that in AM rats (148.74±40.33 μg/L) at M1 (P<0.01). However, it increased to the similar level of AM rats at M3 (P>0.05). Estrogen level in DXM rats sustained in the lower level at each time point (93.13±31.27, 91.77±33.14, 98.83±10.58 μg/L) compared with AM rats (148.74±40.33, 140.01±28.46, 126.64±69.12 μg/L, P<0.05). The levels of PINP and β-CTX in two glucocorticoid-treated groups were significantly higher than those in AM rats at each time point (P<0.01). Additionally, the level of PINP in PRE rats (1410.33±882.40, 2089.23±1623.61, 1546.88±644.68μg/L) was higher than that in DEX rats at each time point (258.70±139.42, 220.89±92.82, 483.36±225.82 μg/L, P<0.05). Conclusion The effect of DXM on bone mass loss is more powerful than PRE, which might be caused by more reduction of estrogen level and bone formation activity. |