Objective To investigate the feasibility of using the porcine small intestinal submucosa (SIS) as a kind of the new tissue engineered materials to repair the rat full skin defect. Methods Twenty-eight 6-week-old SD rats weighing 300-350 g were selected in this experimental study. Two 2-cm-diameter round full skin defects were made on the rat back. The upper round defect was used as the blank group, which had no coverings, and the lower round defect was used as the SIS group. SIS that had been produced earlier was transplanted in the defected area. At 3 days, 1, 2, 3, 4, 6 and 8 weeks after the transplantation, the observation was made on the repaired skin conditions, the HE stain, and the repaired skin proportion. Results There was no infection in the two groups. The repairing speed in the SIS group was faster than that in the blank group at 2, 3, 4 and 6 weeks after the transplantation. The skin repaired by SIS was soft and elastic in texture, which had the same high level as the normal skin. The scar tissues in the SIS group were thinner than those in the blank group. The repaired skin proportions at 1, 2, 3, 4, 6 and 8 weeks after the transplantation were 15.72%±3.64%, 43.81%±4.87%, 65.35%±5.63%, 87.95%±4.78%，96.90%±6.89% and 100%, respectively in the SIS group, and 13.42%±5.63%，58.74%±4.48%，76.50%±5.23%，92.30%±5.75% and 100%, respectively in the blank group. Therewas a statistically significant difference between the two groups at 1, 2, 3 and 4 weeks after the transplantation(P＜0.05). Under the microscope, the SIS-repaired skin was observed to have more keratinocytes and collagen tissues, whichwas familiar to the normal skin.Conclusion Porcine SIS can be used as a new kind of the tissue engineered materials to repair the full skin defect.
Objective To compare the effect of small intestinal submucosa(SIS)and polypropylene mesh(PPM) on repairing abdominal wall defects in rats, and toprobe into the feasibility of using SIS to repair the abdominal wall defects. Methods 100 SD rats(50 males and 50 females)were randomly divided into 2 groups(n=50). Their weight ranged from 200 to 250 g.Full thickness abdominal wall defects (2 cm×2 cm) were created by surgery and were repaired with SIS and PPM respectively. At different postoperative time (1st, 2nd, 4th, 8th and 12th week), animals were sacrificed to make histological observation. The tensile strengthand the development of adhesions were measured and observed. Results 95 animals survived and were healthy after surgery. No inflammatory response and obvious immunoreaction were observed in both groups. One week after operation, the tensile strengthof abdominal wall in SIS group (204.30±5.13 mmHg) was lower than that in PPMgroup(240.0±10.0 mmHg) at 1st week(P＜0.05),and there were no difference at 4th, 8th, 12th week. Adhesions were more marked in PPM group thanthat in SIS group(P＜0.05). Conclusion Both SIS and PPM are histologically compatible when used in rats and can maintain sufficient tensile strength. SIS is superior to PPM in regards to tissue compatibility and adhesion formation.
OBJECTIVE: To review the research advance of the preparation and characteristics of small intestinal submucosa(SIS). METHODS: Recent original articles related to such aspects of small intestinal submucosa were reviewed extensively. RESULTS: Small intestinal submucosa was an easily obtained biomaterial. SIS was a bio-absorbable and degradable material. SIS had tissue specific regeneration properties. CONCLUSION: SIS is a suitable bio-derived material for tissue engineering of blood vessel, muscle tendon, urinary bladder and abdomen.
Objective To investigate effects of the autologous bone mesenchymal stem cells (MSCs) enriched by the small intestinal submucosa (SIS) film implantation on the myocardial structure, cardiac function, and compensator y circulation after myocardial infarction in the goats. Methods Sixteen black goats were selected and divided randomly into the control group (n=8)and the experimental group (n=8). The chronic myocardial infarction models were made by the ligation of the far end of the left anterior desc ending coronary artery. At the same time, MSCs were aspired from the thigh bone of the goats in the experimental group. MSCs were isolated by the centrifu gation through a percoll step gradient and purified by the plating culture and depletion of the non-adherent cells. Primary MSCs were cultured in the DMEM me dium supplemented with the fetal bovine serum in vitro. After that, the cultures were labeled by 5- BrdU. The active cells were transplanted into the SIS film. Six weeks after the ligation, the MSCs-SIS film was implanted by its being sutured onto the infarction area; whereas, the control group underwent a shamoperation. In both groups, echocardiographic measurements were performed before infarction, 6 weeks after infarction and 6 weeks after the MSC-collagen mplantion, respectively, to assess the myocardial structure and ca rdiac function. The left coronary artery angiography was performed with the digi tal subtraction angiography. Results In an assessment of the left ventricular function, at 6 weeks after operation, t he stroke volume and the ejection fraction of the control group and the experim ental group were 42.81±4.91, 37.06±4.75 ml and 59.20%±5.41%, 44.56%±4.23%, respectively (Plt;0.05). The enddisatolic volume and the endsystolic volume of the control group and the experimental group were 72.55±8.13, 83.31±8.61 ml and 29.75±5.98, 46.25±6.68 ml, respectively (Plt;0.05). The maximal velocity of peak E of contral group and experimental group were 54.8 5±6.35 cm/s and 43.14±4.81cm/s (Plt;0.01); and the maximal velocity of peak A o f control group and experimental grouop were 52.33±6.65 cm/s and 56.91±6.34 cm/s (Pgt;0.05). Echocowdiogr aphy sho wing a distinctly dilatation of left ventricle with the ventricular dyskinesia i n contral group, but without the ventricular dyskinesia in experimental group. T he selective-coronary evngiography revealed that the obvious compensatory circu l ation established between the anterior descending branch and the left circumflex branch in the experimental group. Conclusion Implantation of the autologus MSCs enriched by the SIS film can prevent dilatation of the left ventricular chamber and can improve the contractile ability of the myocardium, cardiac function, and collateral perfusion.
Objective To explore the possibility of small intestinal submucosa (SIS) for reconstruction of urethral defect. 〖WTHZ〗Methods Twenty-four male rabbits weredivided into 4 groups: group A (the tubulate SIS graft for urethral repair), group B (control group, urethral tubulate defect), group C (the SIS patch graft forurethral repairs), group D (control group, urethral part defect). Then the regenerative segment was studied with histological technique by hematoxylineosin straining and immunohistological straining for α-actin after 6 and 12 weeks postoperatively. The retrograde urethrography and urodynamics were used to evaluate the function of the regenerative urethra at 12 weeks after operation. Results In groups A and C, at 6 weeks after operation, the luminal surface of matrix was completely covered by urothelium, minimal SIS graft was observed in the extracellular matrix, new smooth-muscle cells was confirmed; however, more inflammatory cells were observed in the host-matrix anastomosis in group A than in group C. At 12 weeks postoperatively, the regenerative tissue was equivalent to the normal urethral tissue and SIS disappeared in group C, but some minimal SIS grafts were observed in group A. In groups B and D, urethral strictures and fibrous connective tissue were observed except ３ cases. The urethrography showed wide smooth urethral in group A and C, meawhile urodynamic evaluation didn’t demonstrat significant difference(P＞0.05) in the bladder volume and the maximum urethral pressure between preoperation and postoperation in group A or group C. Conclusion SIS can be a useful material for urethral repair in rabbits, the SIS patch graft is superior to the tubulate SIS graft in urethra reconstruction.
ObjectiveTo investigate the feasibility of tissue engineered periosteum (TEP) constructed by porcine small intestinal submucosa (SIS) and bone marrow mesenchymal stem cells (BMSCs) of rabbit to repair the large irregular bone defects in allogenic rabbits. MethodsThe BMSCs were cultivated from the bone marrow of New Zealand white rabbits (aged, 2 weeks-1 month). SIS was fabricated by porcine proximal jejunum. The TEP constructed by SIS scaffold and BMSCs was prepared in vitro. Eighteen 6-month-old New Zealand white rabbits whose scapula was incompletely resected to establish one side large irregular bone defects (3 cm×3 cm) model. The bone defects were repaired with TEP (experimental group,n=9) and SIS (control group,n=9), respectively. At 8 weeks after operation, the rabbits were sacrificed, and the implants were harvested. The general condition of the rabbits was observed; X-ray radiography and score according to Lane-Sandhu criteria, and histological examination (HE staining and Masson staining) were performed. ResultsAfter operation, all animals had normal behavior and diet; the incision healed normally. The X-ray results showed new bone formation with normal bone density in the defect area of experimental group; but no bone formation was observed in control group. The X-ray score was 6.67±0.32 in experimental group and was 0.32±0.04 in control group, showing significant difference (t=19.871,P=0.001). The general observation of the specimens showed bone healing at both ends of the defect, and the defect was filled by new bone in experimental group; no new bone formed in the control group. The histological staining showed new bone tissue where there were a lot of new vessels and medullary cavity, and no macrophages or lymphocytes infiltration was observed in the defect area of experimental group; only some connective tissue was found in the control group. ConclusionTEP constructed by porcine SIS and BMSCs of rabbit can form new bone in allogenic rabbit and has the feasibility to repair the large irregular bone defects.
Objective To review the recent progress of the small intestinal submucosa (SIS) in application research of tissue repair and reconstruction. Methods The domestic and international articles on the SIS were reviewed and summarized. Results As a natural extracellular matrix, SIS has outstanding biological advantages, such as good mechanical property, tissue compatibility, and lower immunogenicity. SIS has been used to repair and reconstruct various types of tissue defects in animal models and clinical application, especially in the treatment of hernia, urinary system disease, and refractory skin trauma. The development of the tissue engineering technology expands the field of SIS repair and reconstruction and promotes the intensive study of SIS. However, the long-term effect of SIS in tissue repair and reconstruction still remains to be further observation, while the cell/SIS material construction by tissue engineering technology also needs more studies. Conclusion SIS has a widely promising application future in the tissue repair and reconstruction.
ObjectiveTo prepare the small intestinal submucosa (SIS)-silk composite scaffold for anterior cruciate ligament (ACL) reconstruction, and to evaluate its properties of biomechanics, biocompatibility, and the influence on synovial fluid leaking into tibia tunnel so as to provide a better choice in the clinical application of ACL reconstruction. MethodsThe silk was used to remove sericin and then weaved as silk scaffold, which was surrounded cylindrically by SIS to prepare a composite scaffold. The property of biomechanics was evaluated by biomechanical testing system. The cell biocompatibility of scaffolds was evaluated by live/dead staining and the cell counting kit 8 (CCK- 8). Thirty 6-week-old Sprague Dawley rats were randomly assigned to 2 groups (n=15). The silk scaffold (S group) and composite scaffold (SS group) were subcutaneously implanted. At 2, 4, and 8 weeks after implanted, the specimen were harvested for HE staining to observe the biocompatibility. Another 20 28-week-old New Zealand white rabbits were randomly assigned to the S group and SS group (n=20), and the silk scaffold and composite scaffold were used for ACL reconstruction respectively in 2 groups. Furthermore, a bone window was made on the tibia tunnel. At last, the electric resistance of tendon graft in the bone window was measured and recorded at different time points after 5 mL of 10% NaCl or 5 mL of ink solution was irrigated into the joint cavity recspectively. ResultsThe gross observation showed that the composite scaffold consisted of the helical silk bundle inside which was surrounded by SIS. The maximal load of silk scaffold and composite scaffold was respectively (138.62±11.41) N and (137.05±16.95) N, showing no significant difference (P>0.05); the stiffness was respectively (24.65±2.62) N/mm and (24.21±2.39) N/mm, showing no significant difference (P>0.05). The live/dead staining showed that the cells had good activity on both scaffolds. However, the cells on the composite scaffold had better extensibility. In addition, the cell proliferation curve indicated that no significant difference in the absorbance (A) values was founded between groups at various time points (P>0.05). HE staining showed less inflammatory cells and much more angiogenesis in SS group than in S group at 2, 4, and 8 weeks after subcutaneously implanted (P<0.05), indicating good biocompatibility. Additionally, the starting time points of electric resistance decrease and the ink leakage were both significantly later in SS group than in S group (P<0.05). The duration of ink leakage was significantly longer in SS group than in S group (P<0.05). ConclusionThe SIS-silk composite scaffold has excellent biomechanical properties and biocompatibility and early vacularization after in vivo implantation. Moreover, it can reducing the leakage of synovial fluid into tibia tunnel at the early stage of ACL reconstruction. So it is promising to be an ideal ACL scaffold.
Objective To obtain highly purified and large amount of Schwann cells (SCs) by improved primary culture method, to investigate the biocompatibility of small intestinal submucosa (SIS) and SCs, and to make SIS load nerve growth factor (NGF) through co-culture with SCs. Methods Sciatic nerves were isolated from 2-3 days old Sprague Dawley rats and digested with collagenase II and trypsin. SCs were purified by differential adhesion method for 20 minutes and treated with G418 for 48 hours. Then the fibroblasts were further removed by reducing fetal bovine serum to 2.5% in H-DMEM. MTT assay was used to test the proliferation of SCs and the growth curve of SCs was drawn. The purity of SCs was calculated by immunofluorescence staining for S-100. SIS and SCs at passage 3 were co-cultured in vitro. And then the adhesion, proliferation, and differentiation of SCs were investigated by optical microscope and scanning electron microscope (SEM). The NGF content by SCs was also evaluated at 1, 2, 3, 4, 5, and 7 days by ELISA. SCs were removed from SIS by repeated freeze thawing after 3, 5, 7, 10, 13, and 15 days of co-culture. The NGF content in modified SIS was tested by ELISA. Results The purity of SCs was more than 98%. MTT assay showed that the SCs entered the logarithmic growth phase on the 3rd day, and reached the plateau phase on the 7th day. SCs well adhered to the surface of SIS by HE staining and SEM; SCs were fusiform in shape with obvious prominence and the protein granules secreted on cellular surface were also observed. Furthermore, ELISA measurement revealed that, co-culture with SIS, SCs secreted NGF prosperously without significant difference when compared with the control group (P gt; 0.05). The NGF content increased with increasing time. The concentration of NGF released from SIS which were cultured with SCs for 10 days was (414.29 ± 20.87) pg/cm2, while in simple SIS was (4.92 ± 2.06) pg/cm2, showing significant difference (P lt; 0.05). Conclusion A large number of highly purified SCs can be obtained by digestion with collagenase II and trypsin in combination with 20-minute differential adhesion and selection by G418. SIS possesses good biocompatibility with SCs, providing the basis for further study in vivo to fabricate the artificial nerve conduit.
Objective to determine the modulus of elasticity (E) of small intestinal submucosa (SIS), a new biological graft material. Methods The longitudinal tensile testing was performed on 21 specimens of canine jejunum with the electronic material test machine. Results Stress (σ)strain (ε) data were obtained. It was found that the stress (σ)strain (ε) data fitted the expressionσ＝Kεα very well, the mean correlation coefficients R2 was0.991 6.Then the expression of the modulus of elasticity (E) of SIS was E=K1/ασ1-1/α. The mean values of α and K were 3.966 9 and 374.55，so E=4.3992σ0.75. Conclusion The modulus of elasticity was found to increase with increasing stress. The variations law is similar to that of the vessels. Furthermore when σ is 001333 MPa(100 mmHg),E is about 0.16 MPa, which is similar to that of the vessels.