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@#Meniscectomy is the most common surgery in orthopaedics. The absence of meniscal tissue might be related to irreversible damage to the articular cartilage. Meniscal replacement is a tissue-engineering technique for postmeniscectomy syndrome. Its success depends on the implant integration which was vastly proven in animal model studies. Histological evidence is hard to obtain in humans due to ethical issues. We report a clinical case in which a collagen scaffold meniscal implant was harvested six months after implantation due to mechanical failure. Histological analysis was performed revealing vascularisation not only of the peripheral attachment of the implant but also on the anterior horn. These morphologic findings demonstrate that this implant allows the colonisation by precursor cells and vessels, leading to the formation of a fully functional tissue. This present report is one of the few independent reports of scaffold biological integration in the literature.
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The aim of this article is to study how andrographolide-releasing collagen scaffolds influence rabbit articular chondrocytes in maintaining their specific phenotype under inflammatory environment. Physical blending combined with vacuum freeze-drying method was utilized to prepare the andrographolide-releasing collagen scaffold. The characteristics of scaffold including its surface morphology and porosity were detected with environmental scanning electron microscope (ESEM) and a density instrument. Then, the release of andrographolide from prepared scaffolds was measured by UV-visible spectroscopy. Rabbit chondrocytes were isolated and cultured and seeded on andrographolide-releasing collagen scaffolds. Following culture with normal medium for 3 d, seeded chondrocytes were cultured with medium containing interleukin-1 beta (IL-1β) to stimulate inflammation for 7 d. The proliferation, morphology and gene transcription of tested chondrocytes were detected with Alamar Blue assay, fluorescein diacetate (FDA) staining and reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR) test respectively. The results showed that the collagen scaffolds prepared by vacuum freeze-dry possess a high porosity close to 96%, and well-interconnected chambers around (120.7±17.8) μm. The andrographolide-releasing collagen scaffold continuously released andrographolide to the PBS solution within 15 d, and collagen scaffolds containing 2.22% andrographolide significantly inhibit the proliferation of chondrocytes. Compared with collagen scaffolds, 0.44% andrographolide-containing collagen scaffolds facilitate chondrocytes to keep specific normal morphologies following 7 d IL-1β induction. The results obtained by RT-qPCR confirmed this effect by enhancing the transcription of tissue inhibitor of metalloproteinase-1 ( ), collagen II ( ), aggrecan ( ) and the ratio of / collagen I( ), meanwhile, reversing the promoted transcription of matrix metalloproteinase-1 ( ) and matrix metalloproteinase-13 ( ). In conclusion, our research reveals that andrographolide-releasing (0.44%) collagen scaffolds enhance the ability of chondrocytes to maintain their specific morphologies by up-regulating the transcription of genes like , and , while down-regulating the transcription of genes like and which are bad for phenotypic maintenance under IL-1β simulated inflammatory environment. These results implied the potential use of andrographolide-releasing collagen scaffold in osteoarthritic cartilage repair.
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Objective: To evaluate the effect of the combination of collagen scaffold and brain-derived neurotrophic factor (BDNF) on the repair of transected spinal cord injury in rats. Methods: Thirty-two Sprague-Dawley rats were randomly divided into 4 groups: group A (sham operation group), T 9, T 10 segments of the spinal cord was only exposed; group B, 4-mm T 9, T 10 segments of the spinal cord were resected; group C, 4-mm T 9, T 10 segments of the spinal cord were resected and linear ordered collagen scaffolds (LOCS) with corresponding length was transplanted into lesion site; group D, 4-mm T 9, T 10 segments of the spinal cord were resected and LOCS with collagen binding domain (CBD)-BDNF was transplanted into lesion site. During 3 months after operation, Basso-Beattie-Bresnahan (BBB) locomotor score assessment was performed for each rat once a week. At 3 months after operation, electrophysiological test of motor evoked potential (MEP) was performed for rats in each group. Subsequently, retrograde tracing was performed for each rat by injection of fluorogold (FG) at the L 2 spinal cord below the injury level. One week later, brains and spinal cord tissues of rats were collected. Morphological observation was performed to spinal cord tissues after dehydration. The thoracic spinal cords including lesion area were collected and sliced horizontally. Thoracic spinal cords 1 cm above lesion area and lumbar spinal cords 1 cm below lesion area were collected and sliced coronally. Coronal spinal cord tissue sections were observed by the laser confocal scanning microscope and calculated the integral absorbance ( IA) value of FG-positive cells. Horizontal tissue sections of thoracic spinal cord underwent immunofluorescence staining to observe the building of transected spinal cord injury model, axonal regeneration in damaged area, and synapse formation of regenerated axons. Results: During 3 months after operation, the BBB scores of groups B, C, and D were significantly lower than those of group A ( P0.05). Immunofluorescence staining results of spinal cord tissue sections selected from dorsal to ventral spinal cord showed transected injured areas of spinal cords which were significantly different from normal tissues. The numbers of NF-positive axons in lesion center of group A were significantly larger than those of groups B, C, and D ( P<0.05), and in groups C and D than in group B ( P<0.05), and in group D than in group C ( P<0.05). Conclusion: The combined therapeutic approach containing LOCS and CBD-BDNF can promote axonal regeneration and recovery of hind limb motor function after transected spinal cord injury in rats.
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Objective To analyze and evaluate the effects of the tissue engineering bladder reconstruction on the upper urinary tract structure and function.Methods The 8 male beagles were randomly divided into the two groups:sham-operation group (group A,n=4)and the collagen scaffold repair group (group B,n=4).The bladder defect animal model was established in the group B by using the collagen scaffold materials to repair the bladder.The renal function related biochemical indicators were detec-ted and the renal Doppler ultrasonic examination was performed in each group before repair and in 23 weeks after repair.The speci-mens from the two groups were performed the gross morphology observation and the histology examination on postoperative 24 weeks.Results The renal Doppler ultrasound examination showed the normal kidney morphology and normal blood flow signal.In the general observation,no calculi and neoplasm were found in the kidney and ureter of the experimental dogs.The renal function related biochemical indicators had no statistically significant differences between the two groups(P>0.05).The histological exami-nation indicated that the organization structure was integrity,the nephrons in each group had no obvious pathological changes.Con-clusion Using the collagen scaffold materials to reconstruct the canine bladder has no adverse influence on the upper urinary tract structure and function,this tissue engineering approach has good feasibility.
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Objective To compare the vascularization of collagen scaffolds with or without growth factors and their efficacy on cardiac function in postinfarcted rats underwent surgical ventricular restoration.Methods Collagen scaffolds were activated with 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride chemistry (EDC) as control or continually covalently immobilized with vascular endothelial growth factor (VEGF) and VEGF + basic fibrohlast growth factor (bFGF) as experimental groups.Adult SD male rats underwent left anterior descending artery (LAD) ligation to generate transmural myocardial infarction(MI).Four weeks later,by echocardiography,rats with moderate scar size(25％-35％ akinetic area of freedom wall of left ventricle) were screened out,assigned into 3 groups randomly and received the surgical ventricular restocation (SVR).Then,cardiac function was measured by echocardiography at 1w,2w and 4w after patch implantation.At endpoint of study (4w after patch implantation),the rats were sacrificed and the hearts were harvested.Vascularization of patch were determined by capillary density (evidenced by vWFⅧ staining) or mature vessel density (evidenced by SMA staining) respectively.Results The general mortality of the animal model is 15％ (6/40).A significant improvement of cardiac function was observed in all animals at 1 w after patch implantation but that was better preserved in both cytokine-conjugated groups 4w later (control group vs.VEGF group,P ＜ 0.05,control group vs.VEGF + bFGF group,P ＜ 0.01).More capillaries were present in patch with growth factors (P ＜0.05),while significant functional vessel formation was observed only in VEGF + bFGF group (P ＜0.01 vs.control or VEGF group).Additionally,we identified a positive correlation between heart function and mature vessel density (P =0.0297,r2 =0.998).Conclusion The mechanical property of collagen scaffold can be effectively improved by EDC,the growth factors immobilized in scaffold were in favor of vascularization of patch,which may facilitate the preservation of cardiac function posterior to SVR.
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[Objective]To examine whether collagen scaffold(CS) would strengthen calcium phosphate cement(CPC) in vitro,and to investigate whether CPC enhanced with CS would accelerate the osteogenesis for repairing bone defect in rabbits.[Method] A standard 3-piont flexural test was used to fracture the set specimens and to measure the flexural strength,work-of-fracture(WOF) and elastic modulus of CPC and cpclcs.Both cements were implanted into cylinder cavities drilled in 20 rabbit femoral condyles.After 22 and 54 weeks of implantation,histological observations were performed.[Result]The CS had significant effects on composite of mechanical properties.The CPC/CS had a flexural strength 64.2% higher,WOF 3 933.3% higher,and elastic modulus 45.7% lower than the CPC without CS.At 22 weeks,histological study showed collagen fibers of the CPC/CS composite were entirely resorbed and new bone was formed instead.With unreinforced CPC,there were a little bone formation and biodegradation of cement on the margin but not in the interior of CPC.At 54 weeks,plentiful growing bone and bone marrow-like tissue fully filled in pores created by biodegradation of CPC/CS.Although bone formation and biodegradation of cement were more obvious on the margin of CPC cylinder at 54 weeks than 22 weeks,new bone did not present in the interior of CPC yet.[Conclusion]Collagen scaffold not only reinforces CPC,but also accelerates bone formation in the interior of CPC/CS composite.Therefore,CPC/CS could be novel biomaterial as an endosteal implant.
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The regeneration of lost periodontal tissue is a major goal of therapy. Periodontal ligament cell(PDL) is a specialized connective tissue that connects cementum and alveolar bone to maintain and support teeth in situ and preserve tissue homoeostasis. Bone morphogenetic proteins(BMPs) have shown much potential in the reconstruction of the periodontum by stimulate new bone and new cementum formation. Limitiations of BMP administration to periodontal lesions is high dose delivery, BMP transient biological activity, and low bioavailability of factors at the wound site. Gene delivery method can be alternative treatment strategy to deliver BMPs to periodontal tissue. The purpose of this study is to investigate efficiency of BMP-2 gene delivery with cell-based therapy using PDL cells. PDL cell were transduced with adenoviruses encoding either BMP-2 or Lac-Z gene. To evaluate osteogenic activity of expressed BMP-2 on PDL cells, we investigated secreted BMP-2, cellular activity, ALPase, produced mineralized nodules. To evaluate collagen scaffold as carrier for transduced cell delivery, we examined morphology and secreted BMP-2 of transducd PDL cells on it. BMP-2 transducd PDL cells produced higher levels of BMP-2, ALPase, mineralized nodules than non transduced cells. Cellular activity of transduced cells was showed similar activity to non transduced cells. Transduce cells attached on collagen scaffold secreted BMP-2 at 7day and was showed similar morphology to non transduced cells. These results demonstrated that transduced PDL cells produced biologically active BMP-2 and collagen scaffold could be carrier of transducd cells.
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Humans , Adenoviridae , Biological Availability , Collagen , Connective Tissue , Dental Cementum , Periodontal Ligament , Regeneration , Tooth , Wounds and InjuriesABSTRACT
The purpose of this research is to find out the degree of cartilage regeneration by inserting the atelo- collagen scaffold obtained from dermis of a calf on cartilage defect site. Dissection underneath the perichondrium by the periosteal elevator on both side of ears of six New Zealand white rabbits were made to expose the cartilage, leaving pairs of circular holes 3, 6, 9 mm width with punches. One hole was left for a control, and on the other hole atelo-collagen scaffold of the same size was transplanted. In postoperative 1, 2, 4 weeks, the tissues were dyed. The length of long axis of neocartilage was measured through an optical microscope with a 0.1mm graduation at original magnification, x40. In the first and second week, both group showed no sign of cartilage regeneration. In the fourth week, regeneration on marginal portions was observed on all groups and the average values of length of long axis of neocartilage according to defect size were as follows: In the cases with 3mm defect, it was 0.85+/-0.30mm in the control group, and 1.85+/-0.38mm in the graft group; in the cases with 6 mm defect, 1.33+/-0.58mm in the control group, and 2.25+/-0.46mm in the graft group; and in the cases with 9mm defect, 2.33+/-0.77mm in the control group, and 4.47+/-1.39mm in the graft group. This means that the collagen scaffold has an influence on the regeneration of neocartilage. But the relative ratio of the length of neocartilage to cartilage defect size was not significant in the statistics.