Abstract: Objective · To investigate therapeutic effect of gastrin on steroid-associated osteonecrosis (SAON) in rat model. Methods · Twenty-four SD rats were randomly divided into three groups i.e. normal control group (normal group), SAON control group (SAON group) and SAON treatment group (treatment group). SAON group and treatment group were intravenously injected with lipopolysaccharide 1 time per day (600 μg/kg) for 2 d and meanwhile intramuscularly injected with methylprednisolone 1 time per day (50 mg/kg) for 3 d. Normal group was injected with normal saline of the same volumns. After steroid injections, treatment group was injected with gastrin 1 time per day (800 μg/kg) for 14 d, while SAON group was injected with normal saline of the same volumns. After the treatment, bone trabeculas below femoral head growth plate were dissected in the rats for bone histology. Hematoxylin-eosin (H-E) staining, immunohistochemistry, fluorescence staining and Goldner's trichrome staining were applied in this study. Results · SAON model in rats was successfully established. The result of H-E staining showed that compared with SAON group, thrombus area, number and area of fat cells in the bone marrows of treatment group obviously decreased (all P<0.05). Immunohistochemistry showed that osteogenic transcription factor (Sp7) positive cells in treatment group were more than those in SAON group (P<0.01). Compared with SAON group, osteoid length and area (Goldner′s trichrome staining), and bone formation rate and bone mineralization deposition rate (fluorescence staining) all significantly increased in treatment group (all P<0.01). Conclusion · Gastrin can effectively treat SAON in rats by suppressing thrombus and lipid formation and enhancing boneformation.

Key words: steroid-associated osteonecrosis (SAON), gastrin, bone histomorphometry, rat