Adrenomedullin effect on expression of apoptosis-related protein in bone marrow mesenchymal stem cells under hypoxia / 中国组织工程研究

ABSTRACT

BACKGROUND:Adrenomedulin gene transfection can strength the anti-apoptotic ability of bone marrow mesenchymal stem cels under ischemia and hypoxia, but its mechanism is not yet clear. OBJECTIVE:To investigate the effect of adrenomedulin on the expression of apoptosis-related proteins, Bax, Bcl-2 and Caspase-3, in bone marrow mesenchymal stem cels under hypoxia and ischemia. METHODS:Bone marrow mesenchymal stem cels of Sprague-Dawley rats were isolated, cultured and purified, and then cultured in serum-free medium under hypoxic condition for 0, 3, 6, 9, 12 hours. Then, western blot assay was employed to detect the expression of Bax, Bcl-2 and Caspase-3 so as to determine the optimal hypoxia time that was determined at 6 hours of hypoxia. Depending on whether adrenomedulin pretreatment was done, the cels were divided into control group (with no adrenomedulin pretreatment before hypoxia and ischemia) and adrenomedulin groups with different concentrations (1, 10, 100 μg/L). Afterwards, the expression of Bax, Bcl-2 and Caspase-3 was detected by using western blot assay. RESULTS AND CONCLUSION:(1) After cultured in serum-free medium under hypoxia for 0, 3, 6, 9, 12 hours, the expression of Bax, Bcl-2 and Caspase-3 in bone marrow mesenchymal stem cels were increased (P < 0.05);at 6 hours of hypoxia, the Bax/Bcl-2 ratio and Caspase-3 expression reached the minimum value (P < 0.05). (2) At 6 hours of hypoxia, the expression of Bax and Caspase-3 protein as wel as Bax/Bcl-2 ratio became the lowest in the 100 μg/L group compared with the 1 and 10 μg/L groups, but the expression of Bcl-2 protein reached the peak (P < 0.05). These findings indicate that adrenomedulin can reduce the expression of Bax/Bcl-2 ratio and Caspase-3 protein in bone marrow mesenchymal stem cels cultured in serum-free medium under hypoxic conditions, which is in a dose-dependent manner.