Abstract： Objective To investigate the melatonin signaling transduction pathway in BMSCs from adolescent idiopathic scoiiosis patients. Methods Twenty-four volunteers aged 12-18 years were divided into two groups; AIS group was 15 and control group was 9. The human bone marrow anticoagulated by heparin was obtained from anterior superior iliac spine, and the BMSCs were isolated by density gradient centrifuge from the mononuclear cells, and then were cultivated and serial subcultivated in vitro. P3 cultures were analyzed by the flow cytometry to determine the surface antigens. P3 BMSCs were used to detect the melatonin signaling transduction pathway. The cellular cAMP was elevated using forskolin, and then the BMSCs were treated with melatonin to inhibit the cellular cAMP levels. Results Mononuclear cells were cultivated and subcultivated to P3 culture in vitro, which were analyzed by the flow cytometry, and demonstrated that the expanded mononuclear cells expressed mesenchymal cell markers. The basal cAMP levels of the two groups were very low, after the stimulation of forskolin, cellular cAMP levels increased rapidly in all the patients, but after the stimulation of melatonin at physiological dose or even at pharmacological dose, there was no statistical difference of the inhibition of cAMP between AIS group and control (P > 0. 05). Conclusion Melatonin signaling transduction pathway may be normal in BMSCs from AIS patients.