Antegrade cerebral perfusion during deep hypothermia circulatory arrest attenuates the apoptosis of neurons in porcine hippocampus.

BACKGROUND: Cerebral damage is a major problem after reconstructive surgery of the aortic arch and the descending aorta. Current protective strategies, including deep hypothermia and antegrade cerebral perfusion (ACP), are used to prolong the tolerated duration of circulatory arrest. The aim of the study was to observe the influence of deep hypothermic circulatory arrest (DHCA) and ACP on neuronal apoptosis in the hippocampus. To further elucidate the mechanisms of neurologic injury and protection, we assessed the expression of the antiapoptotic protein Bcl-2 and the proapoptotic protein Bax. METHODS: We randomly divided 18 pigs into 3 groups: The control group (n = 6) received normal-temperature cardiopulmonary bypass (CPB), the DHCA group (core temperature, 18 degrees C; n = 6) received DHCA for 90 minutes, and the third group (DHCA + ACP) (core temperature, 18 degrees C; ACP, flow rate of 30 mL/kg per minute at a pressure of 15-25 mm Hg; n = 6) received DHCA for 90 minutes. Hippocampal tissue was sampled 2 hours after CPB was finished. Bcl-2 and Bax expression was examined by immunohistochemistry. Morphologic changes in hippocampal tissue were measured with transmission electron microscopy. RESULTS: Bax protein levels were significantly higher in the DHCA group than in the other 2 groups (P < .05), whereas Bcl-2 protein levels were significantly higher in the DHCA + ACP group than in the other 2 groups (P < .05). Obvious neuronal apoptosis was observed in the DHCA group but not in the controls, and few apoptotic neurons were seen in the DHCA + ACP group. CONCLUSIONS: DHCA can induce neuronal apoptosis in the hippocampus. ACP during the DHCA period protects cerebral tissue by suppressing apoptosis through decreasing Bax expression and increasing Bcl-2 expression.

[Experimental study of differentiation of canine bone marrow mesenchymal stem cell into fibroblasts in vitro].

OBJECTIVE: To explore the way of stably inducing canine bone marrow mesenchymal stem cells (BMSCs) to differentiate into fibroblasts and myofibroblasts in vitro, and provide seed cells for fabricating tissue engineering heart valves (TEHV). METHODS: Adult canine BMSCs were separated by a gradient centrifugation on Percoll (density 1.073 g/ml), then the cells were incubated in low-glucose Dulbecco Eagle's minimum essential medium (LG-DMEM) with 10% bovine calf serum. Cell phenotype were identified by immunohistochemistry staining. The second and third generation of BMSCs were committedly induced by conditioning culture medium, which were detected by immunohistochemistry staining. The induced-BMSCs were freezed, preserved and resuscitated after 7 d to observe the cell growth, proliferation and function. RESULTS: BMSCs deriving from the bone marrow mononuclear cells separated by a Percoll gradient were positive expression of alpha-smooth muscle antibody, vimentin and negative expression of CD34, laminin. About (50 +/- 3)% induced-BMSCs were positive expression of laminin. Approximately (85 +/- 3)% freezed induced-BMSCs could be resuscitated. And the growth, proliferation and function were well. CONCLUSION: BMSCs could be committedly induced to differentiate into fibroblasts and myofibroblasts in vitro. It is suitable to be the seed cells.