ObjectiveTo evaluate the efficacy of XiaochengqiMixture (XM) on promoting healing of colonic stoma. MethodsForty Wistar rats were divided into two groups randomly after colonectomy: experimental group (n=20) and control group (n=20). In early postoperatively stage rats were given gastric administration of XM in the experimental group and pure water in the control group. On day 3, 7, and 14 after establishment of animal models, laparotomy was performed in two groups of rats, respectively. Anastomotic stoma and surrounding tissues were harvested to detect the context of hydroxyproline and collagen fiber proportion by Masson dying. ResultsOn day 3 after establishment of animal models, hyperplastic collagen with small fiber was observed while no fasciculus was found. Hydroxyproline context and collagen fiber proportion of rats were higher in experimental group than those in control group (Plt;0.05). On day 7 after operation, many fasciculuses were found in two groups of rats, hydroxyproline context and collagen fiber proportion of rats were higher in experimental group than those in control group (Plt;0.01). On day 14 after operation, fasciculuses became bigger and more regular in arrangement, but there was no significant difference between the two groups (Pgt;0.05). ConclusionXM is capable of promoting healing of colonic stoma and might prevent the occurrence of anastomotic fistula.
In order to study the influence of severity of tendon injury on the morphology of collagen fibers during healing process of extensor tendons, 40 female Wistal rats were used for investigation. The rats were divided into 2 groups. Transection of the tendon of extensor digitorum longus was performed in one group, while partial section of the same tendon was performed in the other group. Morphometric analysis was undertaken on the 15th, 30th, 60th and 90th day after operation. The result was that there was no significant difference between the two groups both in distribution and diameter of collagen fibers on the 15th and 30th days (P gt; 0.05). However, there was significent difference between those on the 60th and 90th days (P lt; 0.05). It was concluded that the severity of the tendon injury could influence the morphology of collagen fibers during the late stage of tendon healing.
Objective To investigate the influence of lipopolysaccharide(LPS) on the proliferation and collagen synthesis of normal human skin fibroblasts so as to elucidate its relation with skin wound healing. Methods Fibroblasts wereisolated and cultured in vitro, and then exposed to different doses of LPS(0.005, 0.010, 0.050, 0.100, 0.500, and 1.000 μg/ml) from E.coli055∶B5 respectively. Then the absorbance (A) value of fibroblasts was determined with the colorirneteric thiazolylblue (MTT) assay, and the cell number was counted under inverted phase contrast microscope from the 1st day to the 9th day after LPS administration, and collagen synthesis of fibroblasts in culture medium was measured with the method of pepsin digestion after incorporation of 3Hproline into stable, single-layered, confluent fibroblasts at 7 days after LPS administration. Results Compared with control group, A value increased with the increasing concentration of LPS (0.005 μg/ml 0.500 μg/ml) and LPS of 0.100 μg/mlgroup had the best effect. The difference was remarkable from the 5th day to the 9th day(P＜0.05). A value decreased when challenged with the LPS of 1.000 μg/ml and the difference was remarkable from the 3rd day to the 9th day(P＜0.05). Cell number increased with theadministration of LPS of different concentrations (0.005 μg/ml 0.500 μg/ml) and LPS of 0.100 μg/mlgroup had the best effect. The difference was remarkable from the 1st day to the 6th day(P＜0.05). Cell number decreased remarkably when challenged with LPS of 1.000 μg/ml and the difference was remarkable from the 2nd day to the 9th day(P＜0.05). Collagen synthesis increased when challenged with LPS of different concentrations (0.005 μg/ml 0.500 μg/ml) and the 0.100 μg/ml group had the best effect. However, when the dose of LPS reached 1.000 μg/ml, it inhibited collagensynthesis. Conclusion LPS could promote the proliferation andcollagen synthesis of fibroblasts within a certain range of low doses, but over-high dose ofLPS might inhibit the proliferation and collagen synthesis of fibroblasts, suggesting that LPS of certain concentrations might contribute to wound healing, while excessive LPS has negative effect on wound healing.
OBJECTIVE: To study the expression of type I collagen and its receptor system-integrin alpha 2 beta 1 in different passages of osteoblasts. METHODS: The expression of type I collagen and integrin alpha 2 beta 1 in the primary, sixth and fifteenth passage of osteoblasts were detected by S-P immunohistological staining technique, and their mRNA expression by quantity RT-PCR technique. RESULTS: Type I collagen and integrin alpha 2 beta 1 were expressed in different passages of osteoblasts and there was no significant difference among three passages by immunohistological technique. Their mRNA expression was gradually decreased with subculture. CONCLUSION: Type I collagen promotes the adhesion and phenotype expression of osteoblasts through its receptor-integrin alpha 2 beta 1. The reductive expression of type I collagen-receptor system will decline the phenotype of osteoblasts.
Objective To evaluate the feasibility and the value of the layered cylindric collagenhydroxyapatite composite as a scaffold for the cartilage tissue engineering after an observation of how it absorbs the chondrocytes and affe cts the cell behaviors. Methods The chondrocytes were isolated and multiplied in vitro, and then the chondrocytes were seeded onto the porous collagen／h ydro xyapatite composite scaffold and were cultured in a three-dimensional environme n t for 3 weeks. The effects of the composite scaffold on the cell adhesivity, proliferation, morphological changes, and synthesis of the extracellular matrix were observed by the phase-contrast microscopy, histology, scanning electron micros copy, and immunohistochemistry. Results The pore diameter of the upper layer of the collagen-hydroxyapatite composite scaffold was about 147 μm. and the porosity was 89%; the pore diameter of the bottom layer was about 85 μm and the porosity was 85%. The layered cylindric collagenhydroxyapatite composite scaffold had good hydrophilia. The chondrocytes that adhered to the surface of the scaffold, proliferated and migrated into the scaffold after 24 hours. The chondrocytesattached to the wall of the microholes of the scaffold maintained a rounded morphology and could secrete the extracellular matrix on the porous scaffold. Conclusion The layered cylindric collagenhydroxyapatite composite scaffold has a good cellular compatibility, and it is ber in the mechanical property than the pure collagen. It will be an ideal scaffold for the cartilage tissue enginee ring.
Objective To review the appl ication of collagen and biodegradable polymer composite scaffolds in vascular tissue engineering, and describe the multi-layering vascular scaffolds of collagen-based material in recent years. Methods The l iterature concerning collagen composite scaffold production for scaffold of vascular tissue engineering was extensively reviewed and summarized. Results As one of the structural proteins in natural blood vessel, collagen is widely used in vascular tissue engineering because of good biocompatibil ity, biodegradabil ity, and cell recognition signal. The vascular scaffolds with biological activity and good mechanical properties can be made by collagen-polymer composite materials. In addition, the structure and function of the natural blood vessel can be better simulated by multi-layering vascularscaffolds. Conclusion Collagen-polymer composite material is the hot spot in the research of vascular scaffolds, and multilayering vascular scaffolds have a brill iant future.
Objective To investigate the influence of collagen on the biomechanics strength of tissue engineering tendon. Methods All of 75 nude mice were madethe defect models of calcaneous tendons, and were divided into 5 groups randomly. Five different materials including human hair, carbon fibre (CF), polyglycolic acid (PGA), human hair and PGA, and CF and PGA with exogenous collagen were cocultured with exogenous tenocytes to construct the tissue engineering tendons.These tendons were implanted to repair defect of calcaneous tendons of right hind limb in nude mice as experimental groups, while the materials without collagenwere implanted to repair the contralateral calcaneous tendons as control groups. In the 2nd, 4th, 6th, 8th and 12th weeks after implantation, the biomechanicalcharacteristics of the tissue engineering tendon was measured, meanwhile, the changes of the biomechanics strength were observed and compared. Results From the 2nd week to the 4th week after implantation, the experimental groups were ber than the control groups in biomechanics, there was statistically significantdifference (Plt;0.05). From the 6th to 12th weeks, there was no statisticallysignificant difference between the experiment and control groups (Pgt;0.05). Positivecorrelation existed between time and intensity, there was statistically significant difference (Plt;0.05). The strength of materials was good in human hair,followed by CF, and PGA was poor. Conclusion Exogenous collagen can enhance the mechanics strength of tissue engineering tendon, and is of a certain effect on affected limb rehabilitation in early repair stages.
【Abstract】 Objective Prostaglandin E2 (PGE2) production increases in human tendon fibroblasts after the tendon injuries and repetitive mechanical loading in vitro. To analyze the relations between PGE2 and tendinopathy by observing the changes of collagen content and proportion after the Achilles tendon of rabbits is repeatedly exposed to PGE2. Methods Twenty-four Japanese rabbits (aged 3-4 months, weighing 2.0-2.5 kg, and male or female) were equally randomized into 2 groups according to injection dose of PGE2: low dose group (50 ng) and high dose group (500 ng). Corresponding PGE2 (0.2 mL) was injected into the middle segment of the Achilles tendon of hindlimb, the same dose saline into the same site of the other side as controls once a week for 4 weeks or 8 weeks. The Achilles tendons were harvested at 4 and 8 weeks after injection. HE staining was used to observe the cell structure and matrix, and picric acid-sirius red staining to observe the distribution and types of collagen fibers, and transmission electron microscopy was used to measure the density of the unit area and diameter of collagen fibers. Results HE staining showed that collagen structural damage was observed in low dose and high dose groups. Picric acid-sirius red staining showed that the content of type I collagen significantly decreased while the content of type III collagen significantly increased in experimental side of 2 groups at 4 and 8 weeks after injection when compared with control sides (P lt; 0.05). The content of type I collagen was significantly lower and the content of type III collagen and ratio of type III to type I were significantly higher in high dose group than in low dose group (P lt; 0.05). Transmission electron microscopy showed that the collagen fibers density of unit area was significantly lower and the diameter was significantly smaller in high dose and low dose groups than in the controls (P lt; 0.05), and in high dose group than in low dose group (P lt; 0.05). Conclusion Repeat exposure of the Achilles tendon of rabbit to PGE2 can cause the decrease of type I collagen, the increase of type III collagen, the reverse ratio of type I to type III, reduced unit density of collagen fibers, and thinner collagen fibers diameter, which is related with tendinopathy.
Objective To make an experimental research of the tissue engineered rat submandibular glands (SMG) cells growing on a collagensponge scaffold under an optimal culture condition. Methods The Wistar rat (8 days old) SMG cells of the second generation were seeded onthesurface of the collagen sponge scaffold (5 mm×5 mm×2 mm) and were cultured under a physiologically optimal condition for 3 weeks. At 1, 2 and 3 weeks, the cultured cells were observed on their shapes and structures by the histological examination and the scanning electron microscopy. The cultured cells underwentthe immunohistochemistry research (the cytokratin 813,CK8.13;αsmooth muscular actin,αSMA) staining performed at 3 weeks of the culture, and the amylaseactivity analysis (the Amano method) performed at 1 day, 1, 2 and 3 weeks of the culture for an evaluation on the secretion function of the cells; the ultrastructures of the cells were also observed by the transmission electron microscopy for an identification of their origins. Results The observatio n under the scanning electron microscope showed that at 1 week after the cellseeding, the seeded cells were attached to the collagen sponge scaffold surface, with no cell process formed; at 2 weeks the cells increased, with formation of the cell process that was anchored on the collagen sponge scaffold surface; and at 3 weeks, the scaffold surfaceattached cells increased, with formation of thefiliform fibers in the surface layer of the cells. The immunohistochemistry staining showed that the cultured epithelial cells of SMG were bly positive for the specific antibody of CK8.13, and the myoepithelial cells were positive forthe specific antibody of αSMA. The transmission electron microscopy showed that in the surface layer of the cultured epithelial cells of SMG the microvilli,plasm crease, and zymogen granules were observed, with a big and ovalshaped nucleus in the cell, and mitochondria and rough endoplasmic reticulum in the cytoplasm of the cell. The amount of amylase secreted by the cells cultured with thecollagen sponge scaffolds increased at a different degree with an extension of the culturing time. Conclusion The collagen sponge has a satisfactory cell compatibility, and the SMG cells cultured with this kind of collagen sponge can keep their abilities of proliferation and differentiation and theirfunction of secretion. Therefore, this kind of cultured SMG cells can be used as the tissueengineered cells seeded in the scaffold.