BACKGROUND: The key of tissue engineered blood vessel research depends on the appropriate scaffolds. The porcine vascular tubes have frequently been used as candidates for tissue engineering vessel construction, but high immunogenicity and poor mechanical strength limit its application for tissue engineering scaffolds.OBJECTIVE: To prepare a novel tissue engineered vascular scaffold with good mechanical properties and biocompatibility using acellular porcine aorta matrix.METHODS: Porcine aorta was decellularized and modified by thermal cross-linking to improve the mechanical strength and biodegradation properties and to prepare acellular porcine aorta matrix scaffolds. Hematoxylin-eosin staining of histological sections and biomechanical tests were performed to assess the decellularization effects and the mechanical strength of the vascular matrix respectively. Vascular endothelial cells from human umbilical cord veins were isolated and seeded on the acellular matrix scaffolds and cultured in vitro. The biocompatibility was evaluated. RESULTS AND CONCLUSION: After the porcine aorta was treated by 1% Triton X-100 solution for 84 hours, the vessel was fully decellularized, and the architecture of matrix was well preserved. The acellular vascular matrix demonstrated improved biomechanical properties after modification by thermal cross-linking under vacuum at 120 °C for 12 hours. Its tensile strength reached 1.70 MPa. After 7 days of in vitro culture, the seeded endothelial cells formed a typical vascular endothelial layer structure on the surface of acellular matrix, as observed by scanning electron microscopy. Results proved that acellular vascular matrix of porcine aorta could maintain the morphology and structure of natural vessels, its mechanical strength could be greatly improved after successive freeze-drying and thermal cross-linking. A good compatibility between the acellular matrix and endothelial cells of umbilical vein is also achieved.

AIM: To observe the expression of corticotropin releasing hormone (CRH) within the paraventricular nucleus of hypothalamus (PVN) and to explore the relationship between the activated CRH-containing neurons and sympathetic activity in rats with heart failure (HF).METHODS: Healthy male Sprague-Dawley (SD) rats were subjected to coronary artery ligation to induce HF, and chronic intracerebroventricular (ICV) infusion was performed by osmotic pump for 4 weeks.The rats in sham group and HF group were given vehicle (VEH;artificial cerebrospinal fluid 0.25 μL/h).The rats in HF plus treatment group were treated with CRH competitive inhibitor αh-CRH (15 mg/h).Meanwhile, the Lewis rats and Fischer 344 rats for control study also underwent coronary ligation to induce HF or sham surgery.After 4 weeks, left ventricular end-diastolic pressure (LVEDP) and maximum positive/negative change in pressure over time (±dp/dtmax) were determined.The right ventricular-to-body weight (RV/BW) and lung-to-body weight (lung/BW) ratios were calculated.The renal sympathetic nerve activity (RSNA) was recorded and the plasma norepinephrine (NE) level was measured.The expression of CRH in the PVN combined with the plasma adrenocorticotrophic hormone (ACTH) levels were measured.RESULTS: Compared with the sham-SD rats, the HF-SD rats had a greater number of CRH positive neurons in the PVN (accordingly the plasma ACTH levels were increased), accompanied by decreased ±dp/dtmax and increased RSNA, plasma NE, LVEDP, lung/BW and RV/BW.However, ICV treatment with αh-CRH attenuated these changes in the HF-SD rats (P<0.05).Compared with the sham-Fisher 344 rats, the HF-Fisher 344 rats also had a greater number of CRH positive neurons in the PVN (accordingly the plasma ACTH levels were increased).In addition, they had significantly increased RSNA and plasma NE level, higher LVEDP, RV/BW and lung/BW, and lower ±dp/dtmax (P<0.05).Compared with the SHAM-Lewis rats, the HF-Lewis rats had not significantly changed in the above parameters.CONCLUSION: In CHF, the CRH-containing neurons in PVN are activated, thus aggravating cardiac function by increasing sympathoexcitation.

ObjectiveTo evaluate the biological characteristics of rat bone marrow mesenchymal stem cells (BMSCs) transfected with hypoxia-inducible factor-1α(HIF-1 α) gene.MethodsThe rat BMSCs of 3rd generation and the vector expressing HIF-1α gene (pcDNA3.1-HIF-1α) were provided by department of anesthesia,Tangdu Hospital,the 4th Military Medical University.BMSCs expressing HIF-1α gene (BMSCs-HIF-1α cells) were constructed by transfection of vector pcDNA3.1-HIF-1α into BMSCs by means of electroporation.Successful transfection of HIF-1α gene was confirmed by immuno-cytochemistry.Simple BMSCs and BMSCs-pcDNA3.1 cells were used as control cells.After being cultured in hypoxic condition HIF-1α expression was detected by Western blot analysis.Flow cytometry was used to determine the proportion of cells in G1,G2 and S phase and detect apoptosis.The proliferation index (PI) was calculated.The cell growth curve was described by MTT assay and the number of the 3 types of cells was recorded.ResultsA large number of deep blue granules were observed in the nuclei of BMSCs-HIF-1α cells using immuno-cytochemistry but no such granule was found in the two types of control cells.HIF-1α expression was significantly up-regulated and apoptosis rate (the number of apoptotic cella/the total number of cells examined) decreased in BMSC-HIF-1α cells compared with the control cells.The proportion of cells in S and G2 phase was significantly higher and the proportion of cells in G1 phase was significantly lower and PI higher in BMSCs-HIF-1α cells than in the control cells.The number of BMSCs-HIF-lα cells was significantly higher than the number of the two types of control cells at day 3-8 of culture.There was no significant difference in the above variables between BMSCs and BMSCs-pcDNA3.1 cells.ConclusionBMSCs-HIF-1α is successfully constructed by transfection of vector pcDNA3.1-HIF-1α gene into BMSCs by means of electroporation.