To investigate the anti-osteoporotic effects and mechanisms of Sangjisheng (Taxilli Herba) decoction and its effect on the cold-heat symptoms in osteoporosis models.

After ovariectomy, the female rats were injected with hydrocortisone or intragastric administration of thyroxine to establish the ovariectomized osteoporosis, ovariectomized kidney Yang deficiency osteoporosis, and ovariectomized kidney Yin deficiency osteoporosis models. Each group was administered with Sangjisheng (Taxilli Herba) decoction and the corresponding positive drugs respectively. The general state and rectal temperature of the rats were observed, and hot-cold plate residence time was measured. Hematoxylin-eosin (HE) staining was used to observe the bone pathological status, and Goldner staining was applied to determine the bone morphometric parameters. Bone density was measured using a bone densitometer. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of serum bone-specific alkaline phosphatase (BALP), osteocalcin (BGP), type I procollagen amino-terminal propeptide (PINP), tartrate-resistant acid phosphatase 5b (TRACP-5b), deoxypyridinoline (DPD), type I collagen cross-linked carboxy-terminal telopeptide (CTX-I), estradiol (E₂), calcium (Ca) and phosphorus (P). The levels of serum thyroid-stimulating hormone (TSH), triiodothyronine (T₃), thyroxine (T₄), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) as well as the levels of plasma cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were also measured.

(1) Sangjisheng (Taxilli Herba) decoction improved the general state of ovariectomized osteoporotic rats, increased the bone density and improved the pathological status of rat femurs. It reduced the levels of BALP, BGP, TRACP-5b, DPD and CTX-I, and increased the levels of E₂, Ca and P. (2) In the ovariectomized kidney Yang deficiency osteoporotic rats, it increased the reduced rectal temperature, decreased the percentage of hot-cold plate residence time, increased the levels of serum T₃, T₄, ACTH, CORT and plasma cAMP content, as well as the cAMP/cGMP ratio. In the kidney Yin deficiency osteoporotic rats, it decreased the elevated rectal temperature, increased the hot-cold plate residence time percentage and inhibited the elevated levels of serum TSH, T₄, ACTH, CORT and plasma cAMP content.

Sangjisheng (Taxilli Herba) possesses anti-osteoporotic effects, and its mechanism of action is to elevate the estrogen content, inhibit the bone resorption, improve the calcium and phosphorus metabolism disorders and promote the bone calcification and formation. Sangjisheng (Taxilli Herba) has inhibitory effects on both kidney Yin deficiency heat signs and kidney Yang deficiency cold symptoms, similar to the characteristics of traditional Chinese medicine that is neutral in nature applies to both cold and heat syndromes, consistent with the traditional understanding of Sangjisheng (Taxilli Herba) being neutral in nature. Due to its more pronounced effect on kidney Yin deficiency heat symptoms, its medicinal nature is neutral with a slight cooling bias. The mechanism of Sangjisheng (Taxilli Herba) influence on cold-heat symptoms involves regulating the activity of the hypothalamic-pituitary-thyroid (HPT) axis and the hypothalamic-pituitary-adrenal (HPA) axis, normalizing the suppressed HPT and HPA axes in kidney Yang deficiency syndrome and the hyperactive HPT and HPA axes in kidney Yin deficiency syndrome. It also regulates energy metabolism by modulating cAMP, thereby affecting the cAMP/cGMP ratio.