RESUMO
The accumulation of reactive oxygen species (ROS) within the bone marrow microenvironment leads to diminished osteogenic differentiation and heightened lipogenic differentiation of mesenchymal stem cells residing in the bone marrow, ultimately playing a role in the development of osteoporosis (OP). Mitigating ROS levels is a promising approach to counteracting OP. In this study, a nanozyme composed of magnesium-based zeolitic imidazolate frameworks (Mg-ZIF) was engineered to effectively scavenge ROS and alleviate OP. The results of this study indicate that Mg-ZIF exhibits significant potential in scavenging ROS and effectively promoting osteogenic differentiation of bone mesenchymal stem cells (BMSCs). Additionally, Mg-ZIF was found to inhibit the differentiation of BMSCs into adipose cells. In vivo experiments further confirmed the ability of Mg-ZIF to mitigate OP by reducing ROS levels. Mechanistically, Mg-ZIF enhances the differentiation of BMSCs into osteoblasts by upregulating lipid metabolic pathways through ROS scavenging. The results indicate that Mg-ZIF has potential as an effective therapeutic approach for the treatment of osteoporosis.
Assuntos
Células-Tronco Mesenquimais , Osteoporose , Humanos , Osteogênese/genética , Magnésio , Metabolismo dos Lipídeos/genética , Espécies Reativas de Oxigênio/metabolismo , Células Cultivadas , Diferenciação Celular , Osteoporose/tratamento farmacológico , Osteoporose/genética , Osteoporose/metabolismo , Células da Medula ÓsseaRESUMO
It appears to be more practical and effective to prevent carcinogenesis by targeting the tumor promotion stage. Gap junctional intercellular communication (GJIC) is strongly involved in carcinogenesis, especially the tumor promotion stage. Considerable interest has been focused on the chemoprevention activities of soyasaponin (SS), which are major phytochemicals found in soybeans and soy products. However, less is known about the preventive effects of SS (especially SS with different chemical structures) against tumor promoter-induced inhibition of GJIC. We investigated the protective effects of SS-A1, SS-A2, and SS-I against hydrogen peroxide (H2O2)-induced GJIC inhibition and reactive oxygen species (ROS) production in Buffalo rat liver (BRL) cells. The present results clearly show for the first time that SS-A1, SS-A2, and SS-I prevent the H2O2-induced GJIC inhibition by scavenging ROS in BRL cells in a dose-dependent manner at the concentration range of from 25 to 100 µg/mL. Soyasaponins attenuated the H2O2-induced ROS through potentiating the activities of superoxide dismutase and glutathione peroxidase. This may be an important mechanism by which SS protects against tumor promotion. In addition, various chemical structures of SS appear to exhibit different protective abilities against GJIC inhibition. This may partly attribute to their differences in ROS-scavenging activities.
Assuntos
Comunicação Celular/efeitos dos fármacos , Sequestradores de Radicais Livres/farmacologia , Junções Comunicantes/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Saponinas/farmacologia , Animais , Catalase/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Ensaio Cometa , Dano ao DNA/efeitos dos fármacos , Junções Comunicantes/metabolismo , Glutationa Peroxidase/metabolismo , Hepatócitos/metabolismo , Peróxido de Hidrogênio/efeitos adversos , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/citologia , Fígado/efeitos dos fármacos , Malondialdeído/metabolismo , Ratos , Glycine max/química , Superóxido Dismutase/metabolismoRESUMO
BACKGROUND: Rab3a regulates vesicle secretion and transport. Emerging evidences have shown that extracellular vesicles (EVs) can reach target lesions of injured spinal cords and exert a positive effect on these lesions. However, the molecular mechanism by which Rab3a regulates vesicle secretion to ameliorate spinal cord injury (SCI) is not fully understood. METHODS: An SCI rat model was established which was used to examine the pathological changes and Rab3a expression in spinal cord tissue. Rab3a was overexpressed in the model rats to demonstrate its effect on SCI repair. Rab3a was also knocked down in neuronal cells to verify its role in vesicle secretion and neuronal cells. The binding protein of Rab3a was identified by Co-IP and mass spectrometry. RESULTS: Rab3a was significantly downregulated in SCI rats and Rab3a overexpression promoted SCI repair. Rab3a knockdown inhibited the secretion of neuronal cell-derived EVs. Compared to the EVs from the equal number of control neuronal cells, EVs from Rab3a-knockdown neuronal cells promoted M1 macrophage polarization, which in turn, promoted neuronal cell apoptosis. Mechanistically, STXBP1 was identified as a binding protein of Rab3a, and their interaction promoted the secretion of neuronal cell-derived EVs. Furthermore, METTL2b was significantly downregulated in SCI rats, and METTL2b knockdown significantly reduced Rab3a protein expression. CONCLUSION: These results suggest that Rab3a promotes the secretion of neuronal cell-derived EVs by interacting with its binding protein STXBP1. Neuronal cells-derived EVs inhibited the polarization of M1 macrophages in the spinal cord microenvironment, thereby promoting SCI repair. Our findings provide a theoretical basis for the clinical treatment of SCI.
Assuntos
Traumatismos da Medula Espinal , Animais , Ratos , Macrófagos/metabolismo , Medula Espinal/metabolismo , Traumatismos da Medula Espinal/metabolismoRESUMO
OBJECTIVE: The acute respiratory distress syndrome may complicate postpartum hemorrhagic shock and resuscitation, but its mechanisms are not yet well defined. We studied the lung inflammatory response to postpartum hemorrhagic shock and resuscitation in a rabbit model and the role of the nuclear factor-κB pathway. DESIGN: Randomized, controlled, prospective study. SETTING: University hospital laboratory. SUBJECTS: Nonobstetric (not pregnant nor postpartum) and obstetrical (within 2 hrs postpartum) rabbits. INTERVENTIONS: Nonobstetric and obstetric female New Zealand white rabbits underwent fixed-pressure or fixed-volume hemorrhagic shock for 30 mins and then were rapidly resuscitated with the shed blood and Ringer's solution. Finally, they were either monitored for survival time or euthanized by exsanguination for lung tissue examination 24 hrs after hemorrhage. MEASUREMENTS AND MAIN RESULTS: After hemorrhagic shock and resuscitation, median survival time in obstetric rabbits (3 days) was significantly shorter (p<.05) than that in nonobstetric rabbits (5 days). Compared with nonobstetric rabbits, obstetric rabbits had more severe lung injury as indicated by alveolar and interstitial fluid accumulation and marked neutrophil sequestration and greater lung injury score, myeloperoxidase activity, expression of intercellular adhesion molecule-1, serum tumor necrosis factor-α levels, and nuclear factor-κB activation, and lower serum interleukin-10 levels (p<.05 for all). CONCLUSIONS: After hemorrhage and resuscitation, obstetric rabbits had significantly shorter survival time and more severe lung injury than nonobstetric rabbits. The mechanism may be through upregulation of the signal transductions of the nuclear factor-κB pathways.
Assuntos
Lesão Pulmonar Aguda/etiologia , Pneumonia/etiologia , Período Pós-Parto/fisiologia , Choque Hemorrágico/complicações , Lesão Pulmonar Aguda/patologia , Lesão Pulmonar Aguda/fisiopatologia , Animais , Modelos Animais de Doenças , Feminino , Molécula 1 de Adesão Intercelular/metabolismo , Interleucina-10/sangue , Pulmão/patologia , NF-kappa B/sangue , Peroxidase/metabolismo , Pneumonia/patologia , Pneumonia/fisiopatologia , Gravidez , Coelhos , Choque Hemorrágico/fisiopatologia , Fator de Necrose Tumoral alfa/sangueRESUMO
Introduction: Rheumatoid arthritis (RA), a prevailing chronic progressive autoimmune disease, seriously affects the patient's quality of life. However, there is still a lack of precise treatment and management methods in clinical practice. Previous studies showed that CD8+ T cells take a lead in the progression of RA. Methods: Genes closely related to CD8+T cells in RA were identified through multiple RA datasets, CIBERSORT, and WGCNA algorithms. Further machine learning analysis were performed to identify CD8+T cell-related genes most closely related to RA. In addition, the relationship between these three key genes and 33 cancer species was also explored in this study. Results: In this study, 10 genes were identified to be closely related to CD8+T cells in RA. Machine learning analysis identified 3 CD8+T cell-related genes most closely related to RA: CD8A, GZMA, and PRF1. Discussion: Our research aims to provide new ideas for the clinical treatment of RA.
Assuntos
Artrite Reumatoide , Neoplasias , Humanos , Qualidade de Vida , Linfócitos T CD8-Positivos , Biomarcadores , Artrite Reumatoide/genética , Neoplasias/genéticaRESUMO
An efficient supercritical fluid chromatography-mass spectrometry (SFC-MS) method was developed for the quality evaluation of Panax Notoginseng (Burk) F.H. Chen (P. notoginseng) by combination with chemical pattern recognition (CPR). Design of experiments (DoE) was applied to obtain optimal SFC-MS conditions. Several CPR methods including hierarchical cluster analysis (HCA), principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were employed to establish a classification model based on the peak areas and contents of 12 components in P. notoginseng in order to evaluate the quality difference according to the collecting time (Chunqi and Dongqi) and medicinal parts (fibrous root, rhizome, branch root, and main root). PLS-DA has proved to be a satisfactory method with accurate discrimination of the selected samples. The characteristic variables based on the variable importance in projection (VIP) values were selected using PLS-DA. Three characteristic components (ginsenoside Rg2, ginsenoside Rg1, ginsenoside Rb1) with higher VIP values (>1) were chosen to further build the CPR model. Subsequently, the model was verified by testing another set of samples and the results indicated that the established model was satisfactory. PLS-DA models based on the peak areas of the 12 selected analytes in 30 batches of P. notoginseng could give accurate classification. The obtained results demonstrate that the developed method using SFC-MS and PLS-DA has a great potential for the quality assessment of P. notoginseng.
Assuntos
Cromatografia com Fluido Supercrítico , Ginsenosídeos , Panax notoginseng , Panax , Cromatografia Líquida de Alta Pressão , Ginsenosídeos/análise , Espectrometria de Massas , Panax/química , Panax notoginseng/química , Rizoma/químicaRESUMO
Rheumatoid arthritis (RA) is a chronic, heterogeneous autoimmune disease. Its high disability rate has a serious impact on society and individuals, but there is still a lack of effective and reliable diagnostic markers and therapeutic targets for RA. In this study, we integrated RA patient information from three GEO databases for differential gene expression analysis. Additionally, we also obtained pan-cancer-related genes from the TCGA and GTEx databases. For RA-related differential genes, we performed functional enrichment analysis and constructed a weighted gene co-expression network (WGCNA). Then, we obtained 490 key genes by intersecting the significant module genes selected by WGCNA and the differential genes. After using the RanddomForest, SVM-REF, and LASSO three algorithms to analyze these key genes and take the intersection, based on the four core genes (BTN3A2, CYFIP2, ST8SIA1, and TYMS) that we found, we constructed an RA diagnosis. The nomogram model showed good reliability and validity after evaluation, and the ROC curves of the four genes showed that these four genes played an important role in the pathogenesis of RA. After further gene correlation analysis, immune infiltration analysis, and mouse gene expression validation, we finally selected CYFIP2 as the cut-in gene for pan-cancer analysis. The results of the pan-cancer analysis showed that CYFIP2 was closely related to the prognosis of patients with various tumors, the degree of immune cell infiltration, as well as TMB, MSI, and other indicators, suggesting that this gene may be a potential intervention target for human diseases including RA and tumors.
Assuntos
Artrite Reumatoide , Neoplasias , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Artrite Reumatoide/tratamento farmacológico , Redes Reguladoras de Genes , Humanos , Imunidade Inata , Camundongos , Neoplasias/complicações , Neoplasias/genética , Reprodutibilidade dos TestesRESUMO
Rheumatoid arthritis (RA) is a chronic, heterogeneous autoimmune disease with a high disability rate that seriously affects society and individuals. However, there is a lack of effective and reliable diagnostic markers and therapeutic targets. In this study, we identified diagnostic markers of RA based on RNA modification and explored its role as well as degree of immune cell infiltration. We used the gene expression profile data of three synovial tissues (GSE55235, GSE55457, GSE77298) from the Gene Expression Omnibus (GEO) database and the gene of 5 RNA modification genes (including m6A, m1A, m5C, APA, A-1), combined with cluster analysis, identified four RNA modifiers closely related to RA (YTHDC1, LRPPRC, NOP2, and CLP1) and five immune cells namely T cell CD8, CD4 memory resting, T cells regulatory (Tregs) Macrophages M0, and Neutrophils. Based on the LASSO regression algorithm, hub genes and immune cell prediction models were established respectively in RA and a nomogram based on the immune cell model was built. Around 4 key RNA modification regulator genes, miRNA-mRNA, mRNA-TF networks have been established, and GSEA-GO, KEGG-GSEA enrichment analysis has been carried out. Finally, CLP1 was established as an effective RA diagnostic marker, and was highly positively correlated with T cells follicular helper (Tfh) infiltration. On the other hand, highly negatively correlated with the expression of mast cells. In short, CLP1 may play a non-negligible role in the onset and development of RA by altering immune cell infiltration, and it is predicted to represent a novel target for RA clinical diagnosis and therapy.
RESUMO
Ossification of ligamentum flavum (OLF) is a pathological ectopic ossification in the spinal ligament, leading to spinal canal stenosis, but little was known about its pathogenesis. A previous study has found growth/differentiation factor (GDF)-5 expression at ossified sites of the ligaments from OLF patients. This study aimed to investigate the osteogenic effects of GDF-5 on cultured human ligamentum flavum cells (LFCs). LFCs were isolated from human spinal ligamentum flavum, and treated with or without recombinant human (rh) GDF-5. Alkaline phosphatase (ALP) activity was measured. Expression of osteocalcin was assessed by reverse transcriptase-PCR, Western blotting and immunofluorescence. Matrix mineralization was assessed by alizarin red staining. Activation of mitogen-activated protein kinases (MAPK) ERK1/2, p38 and JNK were detected by Western blotting. We found that rhGDF-5 treatment increased ALP activity and osteocalcin expression in a time- and dose-dependent manner, and induced mineralized nodule form. In addition, rhGDF-5 challenge mediated the ERK1/2 and p38 activation but not JNK. Inhibiting this activation pharmacologically, using U0126, a ERK1/2 inhibitor, or SB203580, a p38 inhibitor, resulted in significantly lower ALP activity and osteocalcin protein expression. The present study shows that rhGDF-5 induces osteogenic differentiation of human LFCs through activation of ERK1/2 and p38 MAPK. These findings give some new insight into the pathogenesis of OLF.
Assuntos
Fator 5 de Diferenciação de Crescimento/farmacologia , Ligamento Amarelo/enzimologia , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Osteogênese , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Fosfatase Alcalina/metabolismo , Butadienos/farmacologia , Diferenciação Celular , Células Cultivadas , Fator 5 de Diferenciação de Crescimento/genética , Fator 5 de Diferenciação de Crescimento/metabolismo , Humanos , Imidazóis/farmacologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Ligamento Amarelo/citologia , Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 3 Ativada por Mitógeno/antagonistas & inibidores , Nitrilas/farmacologia , Osteocalcina/genética , Osteocalcina/metabolismo , Piridinas/farmacologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidoresRESUMO
BACKGROUND AND AIMS: Whole-body vibration (WBV) presents as osteogenic in animal models and young patients, but the effect remains unclear in senior people. The use of alternative tilting during WBV to ameliorate bone mass and bone metabolism, particularly in senior people, has not previously been reported. This study assessed changes in bone mineral density (BMD) and bone metabolism in senior people after six-month treatment of whole-body vibration with alternative tilting (WBVAT). METHODS: Fifty-three senior people (11M/42F, >65 yrs, mean age 77) and 15 adults (4M/11F, 50-60 yrs, mean age 53) were enrolled and assigned randomly to WBVAT (senior: n=27; adult: n=7) and control groups (senior: n=26; adult: n=7), respectively. The WBVAT groups were subjected to vertical vibration (0.5-0.8 g, 45-55 Hz) and alternative tilting (2° tilting angle or 8 mm displacement at 0.4 Hz) 20 minutes per day, 3 days a week, for 6 months. BMD in the lumbar spine and femoral neck was measured at 0, 3 and 6 months, respectively, as well as biochemical markers of bone metabolism, including serum calcium, phosphorus, alkaline phosphatase (ALP), osteocalcin and tartrate resistance acid phosphatase at 0, 1, 3 and 6 months, respectively. RESULTS: After 6-month WBVAT treatment, BMD in the lumbar spine and femoral neck increased significantly by 2.52% and 3.22% for senior people, and 1.63% and 2.05% for adults, respectively. The 6-month WBVAT treatment increased BMD in the senior people, both with and without osteoporosis (OP) and in both men and women, but led to a BMD gain greater in people with OP (p<0.01) and women (p<0.01), respectively. The serum ALP level increased significantly by a net 24.4% in seniors after WBVAT treatment at 3 months; other biochemical markers showed non-significant differences between the WBVAT and control groups. CONCLUSIONS: WBVAT treatment may increase BMD in senior people, particularly those with OP and women. Changes in bone metabolism after WBVAT treatment were not observed in most cases.
Assuntos
Densidade Óssea/fisiologia , Colo do Fêmur/metabolismo , Vértebras Lombares/metabolismo , Osteoporose/terapia , Postura/fisiologia , Vibração/uso terapêutico , Fosfatase Ácida/sangue , Idoso , Idoso de 80 Anos ou mais , Fosfatase Alcalina/sangue , Cálcio/sangue , Desenho de Equipamento , Feminino , Humanos , Isoenzimas/sangue , Masculino , Pessoa de Meia-Idade , Osteocalcina/sangue , Osteogênese/fisiologia , Osteoporose/metabolismo , Osteoporose/fisiopatologia , Fósforo/sangue , Fosfatase Ácida Resistente a TartaratoRESUMO
OBJECTIVE: To study the changes in the biological behavior of bone marrow mesenchymal stem cells (BMSCs) transfected with red fluorescent protein by lentivirus (RFP-BMSCs) seeded on in poly-D, L-lactide acid (PDLLA) scaffolds with bioactive modification by ammonia plasma and Gly-Arg-Gly-Asp-Ser (GRGDS) in vitro. METHODS: Circular sheets of PDLLA scaffolds (8 mm in diameter and 1 mm in thickness) were prepared and aminated with PDLLA (group A) or modified with the peptide conjugate A/PDLLA (group PA), with untreated PDLLA as the control (group P). The RFP-BMSCs were seeded on the scaffold materials and their proliferation and metabolic activity were detected using CyQuant NF and Alamar blue staining. The mineralization on the scaffolds was observed using calcein fluorescent dye under a fluorescent microscope. The adhesion and proliferation of RFP-BMSCs were observed by fluorescent microscope, and scanning electron microscope (SEM) was used to confirm the observed adhesion of the seed cells. RESULTS: The RFP-BMSCs seeded on the 3 scaffolds all showed proliferative activity at different time points after cell seeding, and the cell numbers decreased significantly in the order of PA>A>P (P<0.001). The cell number was significantly greater in group PA than in group A at all the time points except for days 10 (P=0.077) and 12 (P=0.491), and gradually became similar with the passage of time. The metabolic changes of the cells follow a similar pattern of cell proliferation. RFP-BMSCs showed more active proliferation in group A and group PA than in group P. On days 14 and 21, the intensity of green fluorescence decreased in the order of group PA, A and P. The RFP-BMSCs showed better adhesion in group PA than in group A, and the cells in group P appeared more scattered under scanning electron microscope. CONCLUSION: Bioactive modification of PDLLA by ammonia treatment and conjugation with GRGDS peptides may promotes the adhesion, proliferation, metabolism and mineralization of RFP-BMSCs seeded on PDLLA scaffolds.
Assuntos
Células-Tronco Mesenquimais/fisiologia , Osteogênese , Poliésteres/química , Alicerces Teciduais/química , Células da Medula Óssea/citologia , Adesão Celular , Proliferação de Células , Células Cultivadas , Humanos , Células-Tronco Mesenquimais/citologia , Oligopeptídeos/química , Engenharia Tecidual/métodosRESUMO
OBJECTIVE: To compare the histological features of the thoracic vertebral body growth plates (VBGPs) of rats at different ages and assess their proliferative capability. METHODS: The thoracic VBGPs obtained from rats aged 1 day and 1, 4, 8, 16 and 28 weeks were identified using safranin O-fast green staining, and the height of the hypertrophic zone, proliferative zone, and resting zone were measured. The chondrocytes were isolated from these VBGPs with a modified trypsin-collagenase type II digestion method for primary culture in vitro. The expressions of proliferating cell nuclear antigen (PCNA) mRNA and protein was detected by real time-PCR and Western blotting, respectively. RESULTS: The 1-day- and 1-week-old rats showed significantly greater hypertrophic zone and proliferative zone in the VBGPs than older rats (P<0.01); the proliferative zone was significantly greater in rats aged 4 weeks than in those aged 28 weeks (P<0.05). The resting zone was obviously greater in rats aged 1 day and 1 week than in older rats (P<0.05), and also greater in rats aged 4 weeks than in those aged 16 and 28 weeks (P<0.05). Obvious ossification in the resting zone occurred at 16 weeks, and most of the resting zone became ossified at 28 weeks. The expression of PCNA decreased at both the mRNA and protein levels as the rats grew. CONCLUSION: The 3 zones of VBGPs are greater in rats aged 1 day and 1 week than in older ones. Ossification in the resting zone begins at 16 weeks, and till 28 weeks, most of the resting zone is ossified. The proliferation ability of VBGP chondrocytes decreases with the increase of age of the rats.
Assuntos
Proliferação de Células , Condrócitos/citologia , Lâmina de Crescimento/anatomia & histologia , Antígeno Nuclear de Célula em Proliferação/análise , Vértebras Torácicas/crescimento & desenvolvimento , Fatores Etários , Animais , Animais Recém-Nascidos , Células Cultivadas , Lâmina de Crescimento/citologia , Masculino , RNA Mensageiro/análise , Ratos , Ratos Sprague-DawleyRESUMO
Hypertrophy of the ligamentum flavum (LF) contributes to lumbar spinal stenosis (LSS), and results mainly from fibrosis. Connective tissue growth factor (CTGF) is a profibrotic factor involved in the fibrotic process. This study aimed to evaluate CTGF expression in hypertrophied lumbar LF and the involvement of CTGF in LF hypertrophy. Ten patients with LSS were enrolled in this study. The control group included 10 patients with lumbar disc herniation. LF thickness was measured on the preoperative axial T1-weighted MRI. LF samples were collected during surgery. LF fibrosis was scored by Masson's trichrome staining. CTGF expression was determined by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. Correlation between LF thickness and CTGF expression was analyzed. Human LF cells were cultured and treated with recombinant human (rh) CTGF. Expression of types I and III collagen was determined by real-time PCR and ELISA. The thickness and fibrosis scores of LF in the LSS group were higher than that in the control group (all P < 0.001). CTGF was expressed in the extracellular matrix of all ligament samples, and was significantly higher in the LSS group than that in the control group (P < 0.001). The increase of CTGF expression was positive correlation with the LF thickness (r = 0.969, P = 0.000). rhCTGF treatment increased the mRNA expression and protein synthesis of types I and III collagen of the LF cells (all P < 0.001). Our results suggest that the increased expression of CTGF is associated with hypertrophy of the LF in patients with LSS.
Assuntos
Fator de Crescimento do Tecido Conjuntivo/metabolismo , Ligamento Amarelo/metabolismo , Vértebras Lombares/metabolismo , Estenose Espinal/metabolismo , Estudos de Casos e Controles , Colágeno Tipo I/metabolismo , Colágeno Tipo III/metabolismo , Feminino , Humanos , Hipertrofia/metabolismo , Deslocamento do Disco Intervertebral/metabolismo , Ligamento Amarelo/patologia , Vértebras Lombares/patologia , Masculino , Pessoa de Meia-Idade , Estenose Espinal/patologiaRESUMO
The surface characteristics of scaffolds for bone tissue engineering must support cell adhesion, migration, proliferation, and osteogenic differentiation. In the study, poly(D,L-lactide acid) (PDLLA) scaffolds were modified by combing ammonia (NH(3) ) plasma pretreatment with Gly-Arg-Gly-Asp-Ser (GRGDS)-peptides coupling technologies. The x-ray photoelectron spectroscopy (XPS) survey spectra showed the peak of N1s at the surface of NH(3) plasma pretreated PDLLA, which was further raised after GRGDS conjugation. Furthermore, N1s and C1s in the high-resolution XPS spectra revealed the presence of -C=N(imine), -C-NH-(amine), and -C=O-NH- (amide) groups. The GRGDS conjugation increased amide groups and decreased amine groups in the plasma-treated PDLLA. Confocal microscope and high performance liquid chromatography verified the anchored peptides after the conjugation process. Bone marrow mesenchymal stem cells were co-cultured with scaffolds. Fluorescent microscope and scanning electron microscope photographs revealed the best cell adhesion in NH(3) plasma pretreated and GRGDS conjugated scaffolds, and the least attachment in unmodified scaffolds. Real-time PCR demonstrated that expression of osteogenesis-related genes, such as osteocalcin, alkaline phosphatase, type I collagen, bone morphogenetic protein-2 and osteopontin, was upregulated in the single NH(3) plasma treated and NH(3) plasma pretreated scaffolds following GRGDS conjugation. The results show that NH(3) plasma treatment promotes the conjugation of GRGDS peptides to the PDLLA scaffolds via the formation of amide linkage, and combination of NH(3) plasma treatment and peptides conjugation may enhance the cell adhesion and osteogenic differentiation in the PDLLA scaffolds. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 682-694, 2011.
Assuntos
Osteogênese , Alicerces Teciduais/química , Amidas/química , Amônia , Animais , Adesão Celular , Proliferação de Células , Células Cultivadas , Expressão Gênica , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/fisiologia , Oligopeptídeos/química , Osteogênese/genética , Poliésteres/química , Ratos , Engenharia TecidualRESUMO
OBJECTIVE: To study the feasibility of preparation of the poly-D, L-lactide acid (PDLLA) scaffolds treated by ammonia plasma and subsequent conjugation of Gly-Arg-Gly-Asp-Ser (GRGDS) peptides via amide linkage formation. METHODS: PDLLA scaffolds (8 mm diameter, 1 mm thickness) were prepared by solvent casting/particulate leaching procedure and then treated by ammonia plasma. The consequent scaffolds were labeled as aminated PDLLA (A/PDLLA). The pore size, porosity, and surface water contact angle of groups 0 (un-treated control), 5, 10, and 20 minutes A/PDLLA were measured. A/PDLLA scaffolds in groups above were immersed into the FITC labelled GRGDS aqueous solution which contain 1-[3-(dimethylamino) propyl]-3-ethylcarbodiimide hydrochloride (EDC-HCl) and N-hydroxysuccinimide (NHS), the molar ratio of peptides/EDC*HCL/NHS was 1.5 : 1.5 : 1.0, then brachytely slashed for 24 hours in room temperature. The consequent scaffolds were labelled as peptides conjugated A/PDLLA (PA/PDLLA). The scaffolds in groups 0, 5, 10, and 20 minutes A/PDLLA and groups correspondingly conjugation of peptides were detected using X-ray photoelectron spectroscopy (XPS). The scaffolds in groups of conjugation of peptides were measured by confocal laser scanning microscope and high performance liquid chromatography (HPLC), un-treated and un-conjugated scaffolds employed as control. Bone marrow mesenchymal stem cells (BMSCs) from SD rats were isolated and cultured by whole bone marrow adherent culture method. BMSCs at the 3rd-6th passages were seeded to the scaffolds as follows: 20 minutes ammonia plasma treatment (group A/PDLLA), 20 minutes ammonia plasma treatment and conjugation of GRGDS (group PA/PDLLA), and untreated PDLLA control (group PDLLA). After 16 hours of culture, the adhesive cells on scaffolds and the adhesive rate were calculated. After 4 and 8 days of culture, the BMSCs/scaffold composites was observed by scanning electron microscope (SEM). RESULTS: No significant difference in pore size and porosity of PDLLA were observed between before and after ammonia plasma treatments (P > 0.05). With increased time of ammonia plasma treatment, the water contact angle of A/PDLLA scaffolds surface was decreased, and the hydrophilicity in the treated scaffolds was improved gradually, showing significant differences when these groups were compared with each other (P < 0.001). XPS results indicated that element nitrogen appeared on the surface of PDLLA treated by ammonia plasma. With time passing, the peak N1s became more visible, and the ratio of N/C increased more obviously. After PDLLA scaffolds treated for 0, 5, 10, and 20 minutes with ammonia plasma and subsequent conjugation of peptides, the ratio of N/C increased and the peak of S2p appeared on the surface. The confocal laser scanning microscope observation showed that the fluorescence intensity of PA/PDLLA scaffolds increased obviously with treatment time. The amount of peptides conjugated for 10 minutes and 20 minutes PA/PDLLA was detected by HPLC successfully, showing significant differences between 10 minutes and 20 minutes groups (P < 0.001). However, the amount of peptides conjugated in un-treated control and 0, 5 minutes PA/PDLLA scaffolds was too small to detect. After 16 hours co-culture of BMSCs/scaffolds, the adhesive cells and the adhesive rates of A/PDLLA and PA/PDLLA scaffolds were higher than those of PDLLA scaffolds, showing significant difference between every 2 groups (P < 0.01). Also, SEM observation confirmed that BMSCs proliferation in A/PDLLA and PA/PDLLA groups was more detectable than that in PDLLA group, especially in PA/PDLLA group. CONCLUSION: Ammonia plasma treatment will significantly increase the amount of FITC-GRGDS peptides conjugated to surface of PDLLA via amide linkage formation. This new type of biomimetic bone has stabilized bioactivities and has proved to promote the adhesion and proliferation of BMSCs in PDLLA.