Damaged articular cartilage has very limited capacity for spontaneous healing. Tissue engineering provides a new hope for functional cartilage repair. Creation of an appropriate cell carrier is one of the critical ste...Damaged articular cartilage has very limited capacity for spontaneous healing. Tissue engineering provides a new hope for functional cartilage repair. Creation of an appropriate cell carrier is one of the critical steps for successful tissue engineering. With the supposition that a biomimetic construct might promise to generate better effects, we developed a novel composite scaffold and investigated its potential for cartilage tissue engineering.展开更多
Background Natural articular cartilage has a limited capacity for spontaneous regeneration. Controlled release of transforming growth factor-β1 （TGF-β1） to cartilage defects can enhance chondrogenesis. In this stu...Background Natural articular cartilage has a limited capacity for spontaneous regeneration. Controlled release of transforming growth factor-β1 （TGF-β1） to cartilage defects can enhance chondrogenesis. In this study, we assessed the feasibility of using biodegradable chitosan microspheres as carriers for controlled TGF-β1 delivery and the effect of released TGF-β1 on the chondrogenic potential of chondrocytes. Methods Chitosan scaffolds and chitosan microspheres loaded with TGF-β1 were prepared by the freeze-drying and the emulsion-crosslinking method respectively. In vitro drug release kinetics, as measured by enzyme-linked immunosorbent assay, was monitored for 7 days. Lysozyme degradation was performed for 4 weeks to detect in vitro degradability of the scaffolds and the microspheres. Rabbit chondrocytes were seeded on the scaffolds containing TGF-β1 microspheres and incubated in vitro for 3 weeks. Histological examination and type Ⅱ collagen immunohistochemical staining was performed to evaluate the effects of released TGF-β1 on cell adhesivity, proliferation and synthesis of the extracellular matrix. Results TGF-β1 was encapsulated into chitosan microspheres and the encapsulation efficiency of TGF-β1 was high （90.1%）. During 4 weeks of incubation in lysozyme solution for in vitro degradation, the mass of both the scaffolds and the microspheres decreased continuously and significant morphological changes was noticed. From the release experiments, it was found that TGF-β1 could be released from the microspheres in a multiphasic fashion including an initial burst phase, a slow linear release phase and a plateau phase. The release amount of TGF-β1 was 37.4%, 50.7%, 61.3%, and 63.5% for 1, 3, 5, and 7 days respectively. At 21 days after cultivation, type II collagen immunohistochemical staining was performed. The mean percentage of positive cells for collagen type II in control group （32.7%± 10.4%） was significantly lower than that in the controlled TGF-β1 release group （92.4%±4.8%, 展开更多
Background Microendoscopic discectomy （MED） is a minimally invasive operation that allows rapid recovery from surgery for lumbar disc herniation, but has replaced traditional open surgery in few hospitals because mo...Background Microendoscopic discectomy （MED） is a minimally invasive operation that allows rapid recovery from surgery for lumbar disc herniation, but has replaced traditional open surgery in few hospitals because most surgeons avoid its long learning curve. We evaluated the effectiveness and safety of lumbar MED at stages of spinal surgeons＇ learning curve. Methods Fifty patients receiving MED from June 2002 to February 2003 were divided into chronological groups of ten each： A-E. The control group F was ten MED patients treated later by the same medical team （September-October 2006）. All operations were performed by the same team of spinal surgeons with no MED experience before June 2002. We compared groups by operation time, blood loss, complications and need for open surgery after MED failure. Results Operation times by group were： A, （107±14） minutes; B, （85±13） minutes; C, （55±19） minutes; D, （52±12） minutes; E, （51±13） minutes; and F, （49±15） minutes. Blood loss were： A, （131±73） ml; B, （75±20） ml; C, （48±16） ml; D, （44±17） ml; E, （45±18） ml; and F, （45±16） ml. Both operation time and blood loss in groups C, D, E and F were smaller and more stable compared with groups A and B. Japanese Orthopedic Association assessment （JOA） score of each group in improvement rate immediately and one year after operation were as follows （in percentage）： A, （79.8±8.8）/（89.8±7.7）; B, （78.6±8.5）/（88.5±7.8）; C, （80.8±11.3）/（90.8±6.7）; D, （77.7±11.4）/（88.9±9.3）; E, （84.0±8.7）/（89.6±9.0）; and F, （77.8±11.6）/ （86.9±8.4）. Groups showed no statistical difference in improvement rates. Complications developed in three patients in group A, two in group B, and none in the other groups. Conclusions Spinal surgeons performing MED become proficient after 10-20 operations, when their skill becomes fairly sophisticated. Patients＇ improvement rate is the same regardless of surgeons＇ phase of lea展开更多
Polydatin is thought to protect mitochondria in different cell types in various diseases.Mitochondrial dysfunction is a major contributing factor in secondary brain injury resulting from traumatic brain injury.To inve...Polydatin is thought to protect mitochondria in different cell types in various diseases.Mitochondrial dysfunction is a major contributing factor in secondary brain injury resulting from traumatic brain injury.To investigate the protective effect of polydatin after traumatic brain injury,a rat brain injury model of lateral fluid percussion was established to mimic traumatic brain injury insults.Rat models were intraperitoneally injected with polydatin(30 mg/kg)or the SIRT1 activator SRT1720(20 mg/kg,as a positive control to polydatin).At 6 hours post-traumatic brain injury insults,western blot assay was used to detect the expression of SIRT1,endoplasmic reticulum stress related proteins and p38 phosphorylation in cerebral cortex on the injured side.Flow cytometry was used to analyze neuronal mitochondrial superoxide,mitochondrial membrane potential and mitochondrial permeability transition pore opened.Ultrastructural damage in neuronal mitochondria was measured by transmission electron microscopy.Our results showed that after treatment with polydatin,release of reactive oxygen species in neuronal mitochondria was markedly reduced;swelling of mitochondria was alleviated;mitochondrial membrane potential was maintained;mitochondrial permeability transition pore opened.Also endoplasmic reticulum stress related proteins were inhibited,including the activation of p-PERK,spliced XBP-1 and cleaved ATF6.SIRT1 expression and activity were increased;p38 phosphorylation and cleaved caspase-9/3 activation were inhibited.Neurological scores of treated rats were increased and the mortality was reduced compared with the rats only subjected to traumatic brain injury.These results indicated that polydatin protectrd rats from the consequences of traumatic brain injury and exerted a protective effect on neuronal mitochondria.The mechanisms may be linked to increased SIRT1 expression and activity,which inhibits the p38 phosphorylation-mediated mitochondrial apoptotic pathway.This study was approved by the Animal Care and Use Committe展开更多
Objective： To study the feasibility of regenerating a whole menisci using poly-（3- hydroxybutyrate-co-3-hydroxyvalerate） （PHBV） scaffolds loaded with meniscal cells in rabbits undergoing total meniscectomy, and t...Objective： To study the feasibility of regenerating a whole menisci using poly-（3- hydroxybutyrate-co-3-hydroxyvalerate） （PHBV） scaffolds loaded with meniscal cells in rabbits undergoing total meniscectomy, and to explore its protective effect on carti- lage degeneration. Methods： A solvent casting and particulate leaching technique was employed to fabricate biodegradable PHBV scaffolds into a meniscal shape. The proliferated meniscal cells were seeded onto the polymer scaffolds, transplanted into rabbit knee joints whose lateral menisci had been removed. Eight to 18 weeks after transplantation, the rege- nerated neomenisci were evaluated by gross and histologi- cal observations. Cartilage Mankin score. degeneration was assessed by Results： Eighteen weeks after transplantation, the implants formed neomenisci. Hematoxylin and eosin （HE） staining of the neomenisci sections revealed regeneration of fibrocartilage. Type I collagen in the neomenisci was also proved similar to normal meniscal tissue by immunohis-tochemical analysis and Sirius scarlet trinitrophenol staining. Articular cartilage degeneration was observed 8 weeks af- ter implantation. It was less severe as compared with that in total meniscectomy controls and no further degeneration was observed at 18 weeks. At that time, the regenerated neomenisci strongly resembled normal meniscal fibrocarti- lage in gross and histological appearance, and its mechani- cal property was also close to that of normal meniscus. Conclusions： The present study demonstrates the feasibility of tissue-engineering a whole meniscal structure in total meniscectomy rabbit models using biodegradable PHBV scaffolds together with cultured allogeneic meniscal cells. Cartilage degeneration is decreased. But long-term in vivo investigations on the histological structure and cartilage degeneration of the neomenisci regenerated by this method are still necessary to determine the clinical potential of this tissue engineering avenue.展开更多
基金This study was supported by a grant from Guangdong ProvincialScience &Technology Project, China (No. 2003A302102).
文摘Damaged articular cartilage has very limited capacity for spontaneous healing. Tissue engineering provides a new hope for functional cartilage repair. Creation of an appropriate cell carrier is one of the critical steps for successful tissue engineering. With the supposition that a biomimetic construct might promise to generate better effects, we developed a novel composite scaffold and investigated its potential for cartilage tissue engineering.
基金the National Natural Science Foundation of China (No. 30000056)the Science and Technology Project Foundation of Guangdong Province (No.2003A302102).
文摘Background Natural articular cartilage has a limited capacity for spontaneous regeneration. Controlled release of transforming growth factor-β1 （TGF-β1） to cartilage defects can enhance chondrogenesis. In this study, we assessed the feasibility of using biodegradable chitosan microspheres as carriers for controlled TGF-β1 delivery and the effect of released TGF-β1 on the chondrogenic potential of chondrocytes. Methods Chitosan scaffolds and chitosan microspheres loaded with TGF-β1 were prepared by the freeze-drying and the emulsion-crosslinking method respectively. In vitro drug release kinetics, as measured by enzyme-linked immunosorbent assay, was monitored for 7 days. Lysozyme degradation was performed for 4 weeks to detect in vitro degradability of the scaffolds and the microspheres. Rabbit chondrocytes were seeded on the scaffolds containing TGF-β1 microspheres and incubated in vitro for 3 weeks. Histological examination and type Ⅱ collagen immunohistochemical staining was performed to evaluate the effects of released TGF-β1 on cell adhesivity, proliferation and synthesis of the extracellular matrix. Results TGF-β1 was encapsulated into chitosan microspheres and the encapsulation efficiency of TGF-β1 was high （90.1%）. During 4 weeks of incubation in lysozyme solution for in vitro degradation, the mass of both the scaffolds and the microspheres decreased continuously and significant morphological changes was noticed. From the release experiments, it was found that TGF-β1 could be released from the microspheres in a multiphasic fashion including an initial burst phase, a slow linear release phase and a plateau phase. The release amount of TGF-β1 was 37.4%, 50.7%, 61.3%, and 63.5% for 1, 3, 5, and 7 days respectively. At 21 days after cultivation, type II collagen immunohistochemical staining was performed. The mean percentage of positive cells for collagen type II in control group （32.7%± 10.4%） was significantly lower than that in the controlled TGF-β1 release group （92.4%±4.8%,
文摘Background Microendoscopic discectomy （MED） is a minimally invasive operation that allows rapid recovery from surgery for lumbar disc herniation, but has replaced traditional open surgery in few hospitals because most surgeons avoid its long learning curve. We evaluated the effectiveness and safety of lumbar MED at stages of spinal surgeons＇ learning curve. Methods Fifty patients receiving MED from June 2002 to February 2003 were divided into chronological groups of ten each： A-E. The control group F was ten MED patients treated later by the same medical team （September-October 2006）. All operations were performed by the same team of spinal surgeons with no MED experience before June 2002. We compared groups by operation time, blood loss, complications and need for open surgery after MED failure. Results Operation times by group were： A, （107±14） minutes; B, （85±13） minutes; C, （55±19） minutes; D, （52±12） minutes; E, （51±13） minutes; and F, （49±15） minutes. Blood loss were： A, （131±73） ml; B, （75±20） ml; C, （48±16） ml; D, （44±17） ml; E, （45±18） ml; and F, （45±16） ml. Both operation time and blood loss in groups C, D, E and F were smaller and more stable compared with groups A and B. Japanese Orthopedic Association assessment （JOA） score of each group in improvement rate immediately and one year after operation were as follows （in percentage）： A, （79.8±8.8）/（89.8±7.7）; B, （78.6±8.5）/（88.5±7.8）; C, （80.8±11.3）/（90.8±6.7）; D, （77.7±11.4）/（88.9±9.3）; E, （84.0±8.7）/（89.6±9.0）; and F, （77.8±11.6）/ （86.9±8.4）. Groups showed no statistical difference in improvement rates. Complications developed in three patients in group A, two in group B, and none in the other groups. Conclusions Spinal surgeons performing MED become proficient after 10-20 operations, when their skill becomes fairly sophisticated. Patients＇ improvement rate is the same regardless of surgeons＇ phase of lea
基金supported by the National Natural Science Foundation of China,No.81501690(to ZTG)the Scientific Research Staring Foundation for Talent Introduction for Southern Medical University(to MM)
文摘Polydatin is thought to protect mitochondria in different cell types in various diseases.Mitochondrial dysfunction is a major contributing factor in secondary brain injury resulting from traumatic brain injury.To investigate the protective effect of polydatin after traumatic brain injury,a rat brain injury model of lateral fluid percussion was established to mimic traumatic brain injury insults.Rat models were intraperitoneally injected with polydatin(30 mg/kg)or the SIRT1 activator SRT1720(20 mg/kg,as a positive control to polydatin).At 6 hours post-traumatic brain injury insults,western blot assay was used to detect the expression of SIRT1,endoplasmic reticulum stress related proteins and p38 phosphorylation in cerebral cortex on the injured side.Flow cytometry was used to analyze neuronal mitochondrial superoxide,mitochondrial membrane potential and mitochondrial permeability transition pore opened.Ultrastructural damage in neuronal mitochondria was measured by transmission electron microscopy.Our results showed that after treatment with polydatin,release of reactive oxygen species in neuronal mitochondria was markedly reduced;swelling of mitochondria was alleviated;mitochondrial membrane potential was maintained;mitochondrial permeability transition pore opened.Also endoplasmic reticulum stress related proteins were inhibited,including the activation of p-PERK,spliced XBP-1 and cleaved ATF6.SIRT1 expression and activity were increased;p38 phosphorylation and cleaved caspase-9/3 activation were inhibited.Neurological scores of treated rats were increased and the mortality was reduced compared with the rats only subjected to traumatic brain injury.These results indicated that polydatin protectrd rats from the consequences of traumatic brain injury and exerted a protective effect on neuronal mitochondria.The mechanisms may be linked to increased SIRT1 expression and activity,which inhibits the p38 phosphorylation-mediated mitochondrial apoptotic pathway.This study was approved by the Animal Care and Use Committe
基金This study was supported by the fundation of Hi-tech Research and Development Program （863 Program） project （2008AA02Z437） and the National Natural Science Foundation of China （No. 30600632）.
文摘Objective： To study the feasibility of regenerating a whole menisci using poly-（3- hydroxybutyrate-co-3-hydroxyvalerate） （PHBV） scaffolds loaded with meniscal cells in rabbits undergoing total meniscectomy, and to explore its protective effect on carti- lage degeneration. Methods： A solvent casting and particulate leaching technique was employed to fabricate biodegradable PHBV scaffolds into a meniscal shape. The proliferated meniscal cells were seeded onto the polymer scaffolds, transplanted into rabbit knee joints whose lateral menisci had been removed. Eight to 18 weeks after transplantation, the rege- nerated neomenisci were evaluated by gross and histologi- cal observations. Cartilage Mankin score. degeneration was assessed by Results： Eighteen weeks after transplantation, the implants formed neomenisci. Hematoxylin and eosin （HE） staining of the neomenisci sections revealed regeneration of fibrocartilage. Type I collagen in the neomenisci was also proved similar to normal meniscal tissue by immunohis-tochemical analysis and Sirius scarlet trinitrophenol staining. Articular cartilage degeneration was observed 8 weeks af- ter implantation. It was less severe as compared with that in total meniscectomy controls and no further degeneration was observed at 18 weeks. At that time, the regenerated neomenisci strongly resembled normal meniscal fibrocarti- lage in gross and histological appearance, and its mechani- cal property was also close to that of normal meniscus. Conclusions： The present study demonstrates the feasibility of tissue-engineering a whole meniscal structure in total meniscectomy rabbit models using biodegradable PHBV scaffolds together with cultured allogeneic meniscal cells. Cartilage degeneration is decreased. But long-term in vivo investigations on the histological structure and cartilage degeneration of the neomenisci regenerated by this method are still necessary to determine the clinical potential of this tissue engineering avenue.
