The effect of Mongolian Medicine Chagan Gaoyou-4 Powder on bone mineral density induced by retinoic acid in rats

Objective: To investigate the effects of Chagan-Gaoyou-4 powder on spine bone mineral density and serum estrogen and estrogen receptor alpha (ERa) and estrogen receptor beta (ERβ) protein expression in bone tissue induced by retinoic acid in rats. Methods: Sixty 3-month-old SPF female SD rats were randomly divided into model group (retinoin group), normal group (SHAM group), Mongolian medicine group (Chagan-Gaoyou 4 group), and control group (Gushukang granule group). After 14 days of administration, spinal Bone Mineral Density (BMD) was measured, and external manifestations were observed. Results: Compared with the SHAM group, the BMD values of all medication groups decreased (P < 0.05, P < 0.001). Compared with the model group, the spinal BMD value of the Chagan Gaoyou-4 group was increased after 21 days of treatment, and the difference was statistically significant (P < 0.01, P < 0.05). After 21 days, the spinal BMD value of all treatment groups was increased (P < 0.05), the spinal BMD value was also increased, especially Chagan Gaoyou-4 group was more obviously increased (P < 0.05). Compared with the normal group, ERa and ERβ levels in the model group were significantly decreased (P < 0.001), and ERa and ERβ levels in all drug groups were significantly increased (P < 0.001) compared with the model group. After 21 days of treatment, there was no significant difference among the three treatment groups (P > 0.05). ERa and ERβ levels in the Chagan Gaoyou-4 group were higher than those in the model group (P < 0.05), but there was no significant difference between the group and the Gushukang granule group (P > 0.05). The E2 content of the Chagan Gaoyou-4 group was higher than that of the model group (P < 0.05). The mRNA expression of estrogen receptor ERa and ERβ in bone tissue of the left proximal femur was detected by RT-PCR. Compared with the model group, the expression of ERa and ERβ mRNA in the Chagan Gaoyou-4 group and Gushukang granule group was increased. Compared with the model group, ERp mRNA expression was increased in the Chagan Gaoyou-4 powder medium-dose group. Compared with the Gushukang granule group, there was no significant difference in ERm RNA expression in the Chagan Gaoyou-4 dose groups. Chagan Gaoyou-4 can up-regulate the expression of ERa and ERβ induced by retinoic acid in rats, indicating that the Chagan Gaoyou-4 powder group may promote bone formation, regulate bone resorption, improve bone mineral density, and achieve the purpose of preventing and treating OP by increasing estrogen level, stimulating estrogen receptor, and increasing the expression of ERa and ERβ in bone tissue. Conclusion: Chagan-Gaoyu-4 powder may have estrogen-like effects on the bone tissue of rats induced by retinoic acid and may increase the level of serum estrogen, ERa, and ERβ protein expression, thereby improving the spinal BMD of experimental rats. The Chagan-Gaoyou-4 powder group could improve the general condition of osteoporosis induced by retinoic acid in rats.