Objective To study and test novel hybrid valves in vitro and in vivo, and provide basis for clinical use in future. Methods The hybrid valves were fabricated from decellularized porcine aortic valves coated with poly (3-hydroxybutyrate-co-3hydroxyhexanoate, PHBHHx).（1）In the mechanical test in vitro, the uniaxial tensile biomechanics test of the fresh (n=12), uncoated (n=12) and hybrid valve leaflets (n=12) were investigated. (2）In study in vivo, hybrid valves(n=5) implanted in pulmonary position in sheep without cardiopulmonary bypass. Uncoated grafts (n=5) used as control. The specimens of the hybrid or uncoated valve in sheep were explanted and examined by scanning electron microscopy, histology, calcium content and immunofluorescence staining 18 weeks after surgery. Results The mechanical test in vitro revealed that coating with PHBHHx increased maximal tensile strength of hybrid valves compared with the fresh and uncoated state (P＜0.05). The results in vivo indicated the hybrid valves maintained original shape and softness. Immunofluorescence staining for CD31 confirmed that the surface of hybrid valve was covered by confluent CD31+ cells.The interstitium of hybrid valve indicated that smooth muscle actin (SMA)+ cells population were similar to native valvular tissue. The calcium content of hybrid valve was significantly lower than that of uncoated valve leaflets (P＜0.05). Conclusion Decellularized porcine aortic valves coated with PHBHHx have good biological and biomechanical characteristics. The hybrid valve may provide superior valve replacement with current techniques.
Objective To compare the effect of the composite skin graft consisting of spl it-thickness skin grafts (STSGs) and porcine acellular dermal matrix (PADM) with STSGs only, and to histologically observe the turnover of the PADM in rats. Methods Twenty female Sprague-Dawley rats, weighing 200-225 g, were included. The size of 4.0 cm × 2.5 cm PADM was implanted into hypoderm of the left side of Sprague-Dawley rats’ back. After 10-14 days, the size of 4.0 cm × 2.5 cm full-thickness skin defects were made on the left to expose the PADM under the skin and the same size of full-thickness skin defects were made on the right of the rats’ back. The excised full-thickness skin was made to STSGs about 0.2 mm by drum dermatome. The defects were grafted with composite skin (STSGs on the PADM, experimental group) and STSGs only (control group). The survival rate, the constraction degree of grafts, and the histological change in grafts area were observed at 2, 4, 8, and 20 weeks after operation. Results At 2 weeks after STSGs (0.2 mm) placed on vascularized PADM, STSGs and PADM adhered together and the composite skin had a good survival. The control group also had a good survival. Histological observations showed that STSGs and PADM grew together, neutrophil ic granulocytes and lymphocytes infiltrated in the PADM and some macrophages around the PADM. Fibrous connective tissues were filled under the STSGs in control group. At 4-8 weeks after transplantation, the composite skin had a good survival and the composite skin was thick, soft, and elastic. STSGs survived almost totally in control group, but the grafts were thin. Histological observations showed that inflammatory reactions of PADM faded gradually in experimental group; scar tissues formed under the STSGs in control group. At 20 weeks after transplantation, composite skin was flat, thick, and elastic in experimental group, but the STSGs were thinner and less elastic in control group. Histological observations showed that histological structures of the PADM were similar to the dermal matrix of rats, and the results showed that the collagen matrix of PADM was gradually replaced by the rats’ collagen matrix. Scar tissues were filled under the STSGs in control group. Wound heal ing rates of experimental group were lower than those of control group at 4 and 8 weeks (P﹤0.05); wound contraction rates of experimental group had lower tendency than those of control group, but showing no significant differences (P gt; 0.05). Conclusion Coverage wound with composite skin which composed of STSGs and PADM could improve wound heal ing qual ity; the composite skin is thicker and better elastic than STSGs only. The collagen matrix of PADM is gradually replaced by rats’ collagen matrix.
Objective To develop a new kind of skin substitute, selective acellular porcine skin, to cover excised wounds in treatment of extensivedeep burns on the basis of controlled de-cell technique. Methods Partial thickness porcine skin was treated with 0.25% trypsin for 2 hours at 37℃ after crosslinked with glutaraldehyde, and then it was glued to a container with the edge embedded with glue. The skin was shaken in 0.5% SDS for 24 hours, and then washed before use. The selective acellular skin was used with micro-autografts on the dermal side to cover 2 surgically excised burn wounds in a patient. The recoveries of function and appearance were observed. Results Morphological observation showed that the treated porcine skin had an intact epithelial layer and an acellular dermis. After being used to cover burn wounds, its acellular dermis could serve as host dermal matrix, and its devitalized epithelial layer could prevent the dermis from drying. The devitalized epithelium wasfinally replaced by host epithelial cells, and the healed wounds could achieve good cosmetic and functional results. Conclusion Selective acellular porcine skin can be used as promising skin substitute to cover excised wounds.
Objective To investigate the effect of porcine small intestinal submucosa extracellular matrix (PSISM) on the vitality and gene regulation of hepatocyte so as to lay the experimental foundation for the application of PSISM in liver tissue engineering. Methods The experiment was divided into two parts: ① BRL cells were cultured with 50, 100, and 200 μg/mL PSISM-medium which were prepared by adding PSISM into the H-DMEM-medium containing 10%FBS in groups A1, B1, and C1, and simple H-DMEM-medium served as a control (group D1); ② BRL cells were seeded on 1%, 2%, and 3% PSISM hydrogel which were prepared by dissolving PSISM in sterile PBS solution containing 0.1 mol/L NaOH in groups A2, B2, and C2, and collagen type I gel served as a control (group D2). At 1, 3, and 5 days after culture, the morphology and survival of liver cells were detected by the Live/Dead fluorescent staining. The cell vitality was tested by cell counting kit-8 (CCK-8) assay. And the relative expressions of albumin (ALB), cytokeratin 18 (CK18), and alpha-fetoprotein (AFP) in hepatocytes were determined by real-time fluorescent quantitative PCR (RT-qPCR). Results The Live/Dead fluorescent staining showed the cells survived well in all groups. CCK-8 results displayed that the absorbance (A) value of group C1 was significantly higher than that of group D1 at 5 days after culture with PSISM-medium, and there was no significant difference between groups at other time points (P>0.05). After cultured with PSISM hydrogels, theA values of groups A2, B2, and C2 were significantly higher than those of group D2 at 3 and 5 days (P<0.05), theA value of group A2 was significantly higher than that of groups B2 and C2 at 5 days (P<0.05), but there was no significant difference between groups at other time points (P>0.05). RT-qPCR showed that the relative expressions of ALB and CK18 mRNA significantly increased and the relative expression of AFP mRNA significantly decreased in groups A1, B1, and C1 when compared with group D1 (P<0.05). The relative expression of CK18 mRNA in group C1 was significantly lower than that in groups A1 and B1 (P<0.05). The relative expressions of ALB and CK18 mRNA were significantly higher and the relative expression of AFP mRNA was significantly lower in groups A2, B2, and C2 than group D2 (P<0.05); the relative expression of CK18 mRNA in group A2 was significantly higher than that in group B2 (P<0.05), and the relative expression of AFP mRNA in group A2 was significantly lower than that in group C2 (P<0.05), but no significant difference was found between other groups (P>0.05). Conclusion PSISM has good compatibility with hepatocyte and can promote the vitality and functional gene expression of hepatocyte. PSISM is expected to be used as culture medium supplement or cell carrier for liver tissue engineering.
At present, most of the bone xenograft for clinical application comes from bovine. In recent years, many studies have been done on the clinical application of porcine xenograft bone. The goal of this study was to evaluate the effect of canine mandibular defects reparation with antigen-extracted porcine cancellous bone by imaging examination. Four dogs’ bilateral mandibular defects were created, with one side repaired with autologous bone (set as control group) while the other side repaired with antigen-extracted porcine cancellous bone (set as experimental group). Titanium plates and titanium screws were used for fixation. Cone beam computed tomography (CBCT), computed tomography (CT), single-photon emission computed tomography (SPECT) were undertaken at week 12 and 24 postoperatively, and SPECT and CT images were fused. The results demonstrated that the remodeling of antigen-extracted porcine cancellous bone was slower than that of autologous bone, but it can still be used as scaffold for jaw defects. The results in this study provide a new choice for materials required for clinical reparation of jaw defects.
Objective To investigate the repair method of type Ⅱc injury in the lateral meniscus popliteal tendon area based on the porcine knee joint. Methods Eighteen commercially available fresh porcine knee joints were randomly divided into 3 groups (n=6). After preparing a type Ⅱc injury in the lateral meniscus popliteal tendon area, and the anterior (group A), posterior (group B), or anterior and posterior (group C) of the popliteal hiatus (PH) was sutured by vertical mattress. The tension meter was used to apply gradient tensions of 2, 4, 6, 8, and 10 N along the tibial plateau horizontally, respectively, to pull the midpoint of the lateral meniscus popliteal tendon area. The displacement values before modeling, after modeling, and after suture were recorded. The reduction value of lateral meniscus displacement and reduction rate after suture were calculated and compared between groups. Results There was no significant difference between groups (P>0.05) in the displacement values before modeling, after modeling, and after suture under different tensions. There was no significant difference between groups A and C (P>0.05) in the reduction value of lateral meniscus displacement and reduction rate after suture under different tensions. The reduction value of lateral meniscus displacement and reduction rate after suture in group B were lower than those in groups A and C. The reduction value of lateral meniscus displacement under tension of 2 N and the reduction rates under tensions of 2, 4, and 6 N between groups A and B showed significant differences (P<0.05). The reduction value of lateral meniscus displacement and the reduction rate under tensions of 2, 4, and 6 N between groups B and C showed significant differences (P<0.05). Conclusion Suturing the anterior area of PH is the key to repairing type Ⅱc injury of lateral meniscus popliteal tendon area.
ObjectiveTo investigate the safety and feasibility of domestic MP1000 robotic surgical system assisted thyroidectomy via submaxillary approach in porcine animal model. MethodThe thyroidectomy process assisted by the MP1000 robotic surgical system via submaxillary approach for a Bama pig in the 960th Hospital of the Joint Logistics Support Force was retrospectively analyzed. ResultsThe operation was performed as planned programme using the MP1000 robotic surgical system without opening, adding or lengthening the surgical incision. There was no mechanical problems during the MP1000 robotic surgical operation. The operative time was 53 min and the estimated intraoperative blood loss was 10 mL. There was no shaking of instruments and robotic arm during the operation, and the 3 surgical instruments cooperated skillfully, the establishment of surgical operation space successfully was completed, the thyroid blood vessels accurately and finely was dissected, and the separation, coagulation and cutting of blood vessels were smoothly completed. The recurrent laryngeal nerve and parathyroid gland were delicately dissected and protected. The carotid sheath, trachea, esophagus, and other important organs around the thyroid did not be damaged. The master-slave mapping frequency was high, and there was no delay sense during the operation. The lens resolution of MP1000 was 1 920×1 080, the surgical field of vision was clear, no visual field was defected and the visual field was stable and not shaking, light source front and intelligent adaptive temperature control system reduced the fogging of the lens, and the lens was scoured for 4 times during the operation. ConclusionAccording to the preliminary results of the experimental animal in this study, MP1000 robotic surgical system can successfully complete thyroidectomy via submaxillary approach in porcine animal model.