Objectives To construct the cancellous bone explant model and a method of culturing these bone tissues in vitro, and to investigate the effect of mechanical load on growth of cancellous bone tissue in vtro. Methods C...Objectives To construct the cancellous bone explant model and a method of culturing these bone tissues in vitro, and to investigate the effect of mechanical load on growth of cancellous bone tissue in vtro. Methods Cancellous bone were extracted from rabbit femoral head and cut into I-ram-thick and 8-ram-diameter slices under sterile conditions. HE staining and scanning electron microscopy were employed to identify the histomorphology of the model after being cultured with a new dynamic load and circulating perfusion bioreactor system for 0, 3, 5, and 7 days, respectively. We built a three-dimensional model using microCT and analyzed the loading effects using finite element analysis. The model was subjected to mechanical load of 1000, 2000, 3000, and 4000 με respectively for 30 minutes per day. After 5 days of continuous stimuli, the activities of alkaline phosphatase （AKP） and tartrate-resistant acid phosphatase （TRAP） were detected. Apoptosis was analyzed by DNA ladder detection and caspase-3/8/9 activity detection. Results After being cultured for 3, 5, and 7 days, the bone explant model grew well. HE staining showed the apparent nucleus in cells at the each indicated time, and electron microscope revealed the living cells in the bone tissue. The activities of AKP and TRAP in the bone explant model under mechanical load of 3000 and 4000 με were significantly lower than those in the unstressed bone tissues （all P〈0.05）. DNA ladders were seen in the bone tissue under 3000 and 4000με mechanical load. Moreover, there was significant enhancement in the activities of caspase-3/8/9 in the mechanical stress group of 3000 and 4000 με （all P〈0.05）. Conclusions The cancellous bone explant model extracted from the rabbit femoral head could be alive at least for 7 days in the dynamic load and circulating perfusion bioreactor system, however, pathological mechanical load could affect the bone tissue growth by apoptosis in vitro. The differentiation of osteobiasts and osteoclasts might be inhibited after the model is stimulated by mechanical load of 3000 and 4000 με.展开更多
Background Endothelial progenitor cells （EPCs） are used in vascular tissue engineering and clinic therapy. Some investigators get EPCs from the peripheral blood for clinic treatment, but the number of EPCs is seldom...Background Endothelial progenitor cells （EPCs） are used in vascular tissue engineering and clinic therapy. Some investigators get EPCs from the peripheral blood for clinic treatment, but the number of EPCs is seldom enough. We have developed the cultivation and purification of EPCs from the bone marrow of children with congenital heart disease, to provide enough seed cells for a small calibre vascular tissue engineering study. Methods The 0.5-ml of bone marrow was separated from the sternum bone, and 5-ml of peripheral blood was collected from children with congenital heart diseases who had undergone open thoracic surgery. CD34＋ and CD34＋NEGFR＋ cells in the bone marrow and peripheral blood were quantified by flow cytometry. CD34＋/VEGFR＋ cells were defined as EPCs. Mononuclear cells in the bone marrow were isolated by Ficoll density gradient centrifugation and cultured by the EndoCult Liquid Medium KitTM. Colony forming endothelial cells was detected. Immunohistochemistry staining for Dil-ac-LDL and FITC-UEA-1 confirmed the endothelial lineage of these cells. Results CD34＋ and CD34＋NEGFR＋ cells in peripheral blood were （0.07±0.05）% and （0.05±0.02）%, respectively. The number of CD34＋ and CD34＋/VEGFR＋ cells in bone marrow were significantly higher than in blood, （4.41±1.47）% and （0.98±0.65）%, respectively （P 〈0.0001）. Many colony forming units formed in the culture. These cells also expressed high levels of Dil-ac-LDL and FITC-UEA-I. Conclusion This is a novel and feasible approach that can cultivate and purify EPCs from the bone marrow of children with congenital heart disease, and provide seed cells for small calibre vascular tissue engineering.展开更多
基金Supported by grants from the National Natural Science Foundation Key Project of China(10832012)the National Natural Science Foundation of China(31370942 and 11072266)
文摘Objectives To construct the cancellous bone explant model and a method of culturing these bone tissues in vitro, and to investigate the effect of mechanical load on growth of cancellous bone tissue in vtro. Methods Cancellous bone were extracted from rabbit femoral head and cut into I-ram-thick and 8-ram-diameter slices under sterile conditions. HE staining and scanning electron microscopy were employed to identify the histomorphology of the model after being cultured with a new dynamic load and circulating perfusion bioreactor system for 0, 3, 5, and 7 days, respectively. We built a three-dimensional model using microCT and analyzed the loading effects using finite element analysis. The model was subjected to mechanical load of 1000, 2000, 3000, and 4000 με respectively for 30 minutes per day. After 5 days of continuous stimuli, the activities of alkaline phosphatase （AKP） and tartrate-resistant acid phosphatase （TRAP） were detected. Apoptosis was analyzed by DNA ladder detection and caspase-3/8/9 activity detection. Results After being cultured for 3, 5, and 7 days, the bone explant model grew well. HE staining showed the apparent nucleus in cells at the each indicated time, and electron microscope revealed the living cells in the bone tissue. The activities of AKP and TRAP in the bone explant model under mechanical load of 3000 and 4000 με were significantly lower than those in the unstressed bone tissues （all P〈0.05）. DNA ladders were seen in the bone tissue under 3000 and 4000με mechanical load. Moreover, there was significant enhancement in the activities of caspase-3/8/9 in the mechanical stress group of 3000 and 4000 με （all P〈0.05）. Conclusions The cancellous bone explant model extracted from the rabbit femoral head could be alive at least for 7 days in the dynamic load and circulating perfusion bioreactor system, however, pathological mechanical load could affect the bone tissue growth by apoptosis in vitro. The differentiation of osteobiasts and osteoclasts might be inhibited after the model is stimulated by mechanical load of 3000 and 4000 με.
基金This study was supported by a grant from Science Foundation of Beijing Education Commission （No. KM200710025022）.
文摘Background Endothelial progenitor cells （EPCs） are used in vascular tissue engineering and clinic therapy. Some investigators get EPCs from the peripheral blood for clinic treatment, but the number of EPCs is seldom enough. We have developed the cultivation and purification of EPCs from the bone marrow of children with congenital heart disease, to provide enough seed cells for a small calibre vascular tissue engineering study. Methods The 0.5-ml of bone marrow was separated from the sternum bone, and 5-ml of peripheral blood was collected from children with congenital heart diseases who had undergone open thoracic surgery. CD34＋ and CD34＋NEGFR＋ cells in the bone marrow and peripheral blood were quantified by flow cytometry. CD34＋/VEGFR＋ cells were defined as EPCs. Mononuclear cells in the bone marrow were isolated by Ficoll density gradient centrifugation and cultured by the EndoCult Liquid Medium KitTM. Colony forming endothelial cells was detected. Immunohistochemistry staining for Dil-ac-LDL and FITC-UEA-1 confirmed the endothelial lineage of these cells. Results CD34＋ and CD34＋NEGFR＋ cells in peripheral blood were （0.07±0.05）% and （0.05±0.02）%, respectively. The number of CD34＋ and CD34＋/VEGFR＋ cells in bone marrow were significantly higher than in blood, （4.41±1.47）% and （0.98±0.65）%, respectively （P 〈0.0001）. Many colony forming units formed in the culture. These cells also expressed high levels of Dil-ac-LDL and FITC-UEA-I. Conclusion This is a novel and feasible approach that can cultivate and purify EPCs from the bone marrow of children with congenital heart disease, and provide seed cells for small calibre vascular tissue engineering.
