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 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 an effective method of culturing the canine bladder smooth muscle cells, observe the morphological characteristics of the bladder smooth muscle cells growing on acellular small intestinal submucosa（SIS） and offer an experimental basis for reconstruction of the bladder smooth muscle structure by the tissue engineering techniques. Methods The enzymetreatment method and the explant method were respectively used to isolate and harvest the canine bladder smooth muscle cells, and then a primary culture of these cells was performed. The canine bladder smooth musclecells were seeded on the SIS scaffold, and the composite of the bladder smooth muscle cells and the SIS scaffold were co cultured for a further observation. At 5,7 and 9 days of the co culture, the specimens were taken; the bladder smooth muscle cells growing on the SIS scaffold were observed by the hematoxylin staining, the HE staining, and the scanning electron microscopy. The composite of the bladder smooth muscle cells on the SIS scaffold was used as the experimental group, and the bladder smooth muscle cells with no SIS were used as the control group. In each group, 9 holes were chosen for the seeded bladder smooth muscle cells, and then the cells were collected at 3, 5 and 7 days for the cell counting after the enzyme treatment. Morphological characteristics of the cells were observed under the phase contrast microscope and the transmission electron microscope. Expression of the cell specific marker protein was assessed by the immunohistochemical examinaiton. The proliferation of the cells was assessed by the cell counting after the seeding on the SIS scaffold. Results The primary bladder smooth muscle cells that had been harvested by the enzyme treatment method were rapidly proliferated, and the cells had good morphological characteristics. After the primary culture in vitrofor 5 days, the bladder smooth muscle cells grew in confluence. When the bladder smooth muscle cells were seeded by the explant method, a small amount of the spindleshaped bladder smooth muscle cells emigrated from the explant at 3 days. The cells were characterized by the welldeveloped actin filaments inthe cytoplasm and the dense patches in the cell membrane under the transmissionelectron microscope. The immunohistochemical staining showed the canine bladdersmooth muscle cells with positive reacting α actin antibodies. The bladder smooth muscle cells adhered to the surface of the SIS scaffold, growing and proliferating there. After the culture in vitro for 5 days, the smooth muscle cells covered all the surface of the scaffold, showing a singlelayer cellular structure. The cell counts at 3, 5 and 7 days in the experimental group were（16.85±0.79）×105，（39.74±2.16）×105 and （37.15±2.02）×105, respectively. Thecell counts in the control group were（19.43±0.54）×105，（34.50±1.85）×105 and （33.07±1.31）×105, respectively. There was a significant difference between the two groups at 5 days （P＜0.05）. ConclusionWith the enzyme treatment method, the primarily cultured canine bladder smooth muscle cells can produce a great amount of good and active cells in vitro. The acellular SIS can offer an excellent bio scaffold to support the bladder smooth muscle cells to adhere and grow, which has provided the technical foundation for a further experiment on the tissue engineered bladder reconstruction.
ObjectiveTo study the feasibility of human adipose-derived stem cells (hADSCs) combined with small intestinal submucosa powder (SISP)/chitosan chloride (CSCl)-β-glycerol phosphate disodium (GP)-hydroxyethyl cellulose (HEC) for adipose tissue engineering. MethodshADSCs were isolated from human breast fat with collagenase type I digestion, and the third passage hADSCs were mixed with SISP/CSCl-GP-HEC at a density of 1×106 cells/mL. Twenty-four healthy female nude mice of 5 weeks old were randomly divided into experimental group (n=12) and control group (n=12), and the mice were subcutaneously injected with 1 mL hADSCs+SISP/CSCl-GP-HEC or SISP/CSCl-GP-HEC respectively at the neck. The degradation rate was evaluated by implant volume measurement at 0, 1, 2, 4, and 8 weeks. Three mice were euthanized at 1, 2, 4, and 8 weeks respectively for general, histological, and immunohistochemical observations. The ability of adipogenesis (Oil O staining), angiopoiesis (CD31), and localized the hADSCs (immunostaining for human Vimentin) were identified. ResultsThe volume of implants of both groups decreased with time, but it was greater in experimental group than the control group, showing significant difference at 8 weeks (t=3.348, P=0.029). The general observation showed that the border of implants was clear with no adhesion at each time point;fat-liked new tissues were observed with capillaries on the surface at 8 weeks in 2 groups. The histological examinations showed that the structure of implants got compact gradually after injection, and SISP gradually degraded with slower degradation speed in experimental group;adipose tissue began to form, and some mature adipose tissue was observed at 8 weeks in the experimental group. The Oil O staining positive area of experimental group was greater than that of the control group at each time point, showing significant difference at 8 weeks (t=3.411, P=0.027). Immunohistochemical staining for Vemintin showed that hADSCs could survive at each time point in the experimental group;angiogenesis was most remarkable at 2 weeks, showing no significant differences in CD31 possitive area between 2 groups (P>0.05), but angiogenesis was more homogeneous in experimental group. ConclusionSISP/CSCl-GP-HEC can use as scaffolds for hADSCs to reconstruct tissue engineered adipose.
Objective To make a comparison between the effects of the small intestinal submucosa (SIS) graft and the insideout vein graft on repairing the peripheral nerve defects. Methods SIS was harvested from the fresh jejunum of the quarantined pig by curetting the musoca, the tunica serosa, and the myometrium; then, SIS was sterilized, dried and frozen before use. Thirty-six male SD rats were divided into 3 groups randomly, with 12 rats in each group. Firstly, the 10mm defects in the right sciatic nerves were madein the rats and were respectively repaired with the SIS graft (Group A), the insideout autologous vein graft (Group B), and the autonerve graft (Group C). At 6 weeks and 12 weeks after the operations, the right sciatic nerves were taken out, and the comparative evaluation was made on the repairing effects by the histological examination, the neural electrophysiological examination, the computerized imaging analysis, and the Trueblue retrograde fluorescence trace. Results The histological examination showed that the regenerated nerve fibers were seen across the defects in the three groups at 6 weeks after the operations. The nerve fibers were denser, the formed nerve myelin was more regular, and the fibrous tissue was less in Group A than in Group B; the nerve regeneration was more similar between Group A and Group C. At 12 weeks after the operations, the neural electrophysiological examination showed that the neural conductive rate was significantly lower in Group B than in Groups A and C (Plt;0.05),but no statistically significant difference was found between Group A and GroupC (Pgt;0.05); the component potential wave amplitude was not statistically different between Group A and Group B; however, the amplitude was significantly lower in Groups A and B than in Group C (Plt;0.05). At 6 weeks and 12 weeks after the operations, the computerized imaging analyses showed that the axiscylinder quantity per area and the nerve-tissue percentage were significantly greaterin Group A than in Group B (Plt;0.05); the average diameter of the regenerated axis cylinder, the axiscylinder quantity per area, and the nerve-tissue percentage were significantly lesser in Group B than in Group C (Plt;0.05). At 12 weeks after the operations, the Trueblue retrograde fluorescence trace revealed that the positivelylabeled neurons were found in the lumbar 3-6 dorsal root ganglion sections in the three groups. Conclusion The small intestinal submucosa graft is superior to the autologous inside-out vein graft in repairing the peripheral nerve defects and it is close to the autonerve graft in bridging the peripheral nerve defects. Therefore, the small intestinal submucosa is a promising biological material used to replace the autonerve graft.
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.
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.
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.
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 study an optimal ratio of small intestinal submucosa (SIS) and (hydroxyapatite-tricalcium phosphate,HA-TCP,SIS/HA-TCP) compositions according to the effect of SIS/HA-TCP compositions with different ratios on repairing rabbit femoral condyle defect. Methods Thirty-six rabbits were made into bone defect models of 6 mm in diameter and 10 mm in depth in both sides of femoral condyles. Three different ratios of SIS/HA-TCP compositions (w/w: 1, 0.5, 0.25) were implanted into rabbit femoral condyle defect. After 2, 4, 8 and 12 weeks of operation, the repair effect wasobserved grossly. The histological evaluations were performed by histological scoring system and computer imaging analysis system. Results The amount of new bone formation in SIS/HA-TCP(0.5) group was more than that in SIS/HA-TCP(1) and SIS/HA-TCP(0.25) groups. Histological observation: In SIS/HA-TCP(1) group, few new bone formation was seen and bone defect was repaired in the 12th week. In SIS/HA-TCP(0.5) group, immature woven bone was found in the defect in the 2nd week; more immature woven bone appeared and formed trabeculae in the 4th week; the regenerated bone was vigorously growing into the interspaces of the implanted materials in the 8th week; the implanted materials was basically replaced by bony structure and the lamellar bone appeared in the 12thweek. The results of SIS/HA-TCP (0.25) group were similar to that of SIS/HA-TCP(0.5) group. The histological scoring was higher in SIS/HA-TCP(0.5) and SIS／HA-TCP(0.25) groups than that in SIS/HA-TCP(1) group (Plt;0.05) in the 2nd, 4th, 8th, and 12th weeks. The scoring was higher in SIS/HA-TCP(0.5) roup than that in SIS/HA-TCP(0.25) group in the 2nd and 12th weeks(P＜0.05). In new bone formation and the degradation of HA-TCP, SIS/HA-TCP(0.5) and SIS／HA-TCPC(0.25) groups were superior to SIS/HA-TCP(1) group(Plt;0.05), SIS/HA-TCP(0.5) group was superior to SIS/HA-TCP(0.25) group (Plt;0.05). Conclusion SIS/HA-TCP(0.5) has better effects of repairing bone defect and it can be used as a reference ratio in constructing bone scaffolds.