Objective  To establish an animal model of osteoporosis combined with liver cirrhosis and conduct preliminary investigation into the effect of liver cirrhosis on bone loss in mice and the underlying mechanisms.

Methods The experimental animals were 25 6-week-old female C57BL/6 mice with a body weight of approximately 20-22 g. A comorbidity model of liver cirrhosis and osteoporosis was established in the mice by ovariectomy combined with carbon tetrachloride (CCl₄) induction. The mice were randomly assigned to 4 groups (n = 5 in each group), including a control group, a liver cirrhosis group, an osteoporosis group, and a cirrhosis and osteoporosis comorbidity group. Pathological changes in the liver were observed via HE staining, Sirius Red staining, and serum liver function indicators. Bone mass and morphological changes were assessed using micro-CT and HE staining. ELISA, Western blot, and immunohistochemistry were performed to assess the expression of insulin-like growth factor-1 (IGF-1) in serum and liver tissues. An additional IGF-1 intervention group was established to investigate the potential role of IGF-1 in the comorbidity of liver cirrhosis and osteoporosis, and changes in bone mass and morphology were analyzed via micro-CT and HE staining.

Results  Compared with the control and osteoporosis groups, the liver cirrhosis and cirrhosis-osteoporosis comorbidity groups exhibited significant inflammatory cell infiltration and collagen fiber deposition in liver tissues, along with markedly increased serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBIL) (P < 0.05). According to the Micro-CT and HE staining results, the cirrhosis-osteoporosis comorbidity group showed reduced bone mass and decreased trabecular numbers in the distal femur compared to those in the osteoporosis group, with the differences being statistically significant (P < 0.05). ELISA, Western blot, and immunohistochemistry demonstrated significantly reduced expression of IGF-1 in the liver and serum of the cirrhosis-osteoporosis comorbidity group (P < 0.05). Notably, exogenous IGF-1 treatment restored bone mass in mice with liver cirrhosis combined with osteoporosis (P < 0.05).

Conclusion  Through ovariectomy combined with CCl₄ induction, a mouse model of liver cirrhosis combined with osteoporosis was successfully established. IGF-1 may serve as a potential molecular mechanism and therapeutic target mediating the liver cirrhosis-osteoporosis comorbidity.