BACKGROUND:Previous studies have demonstrated that hepatocyte growth factor (HGF) gene transfection can improve the effectiveness of bone marrow mesenchymal stem cel transplantation, but the mechanism is stil unclear. OBJECTIVE:To observe the effects of HGF gene transfection on c-MET, Bax, Bcl-2, Caspase-3 of bone marrow mesenchymal stem cel s cultured under hypoxia and serum-free conditions. METHODS:(1) Bone marrow mesenchymal stem cel s were isolated and amplified in vitro by differential adhesion method. The infection efficiency of recombinant adenovirus Ad-HGF in bone marrow mesechymal stem cel s was tested by x-gal staining. (2) Bone marrow mesenchymal stem cel s were cultured under hypoxia and serum-free conditions for 0, 3, 6, 9, 12 hours. RT-PCR and western blot assays were used to evaluate the expression of Bax, Bcl-2, Caspase-3. (3) Bone marrow mesenchymal stem cel s were cultured under hypoxia and serum-free conditions for 6 hours, and RT-PCR and western blot assays were adopted to detect HGF, c-Met, Bax, Bcl-2 and Caspase-3. (4) Cel scratch test was used to detect the effect of HGF transfection on the migration of bone marrow mesenchymal stem cel s cultured under hypoxia and serum-free conditions for 6 hours. RESULTS AND CONCLUSION:(1) Transfection efficiency of bone marrow mesenchymal stem cel s was increased with multiplicity of infection in a dose-dependent manner. When the multiplicity of infection was 150, the transfection efficiency was 96.4%. (2) Expressions of Bax and Bcl-2 were gradual y increased with hypoxia time (P<0.05). The Bax/Bcl-2 ratio and Caspase-3 expression reach the minimum at 6 hours of hypoxia (P<0.05). (3) Compared with the control and Ad-LacZ groups, the expressions of HGF, c-Met, Bcl-2 increased, and the expressions of Bax and Caspase-3 decreased in the Ad-HGF group after 6 hours of culture under hypoxia and serum-free conditions (P<0.05). There was no significant difference between the control and Ad-LacZ groups. (4) The mobility of bone marrow mesenchymal stem cel s was higher in the Ad-HGF group than the control group and Ad-LacZ groups after 6 hours of culture under hypoxia (P<0.05). These findings indicate that transfection of HGF in bone marrow mesenchymal stem cel s can increase the expression of c-Met, Bcl-2 and decrease the expression of Bax, Caspase-3 under hypoxia and serum-free conditions, which also enhance the mobility of bone marrow mesenchymal stem cel s under hypoxia and serum-free conditions.

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.