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.
【Abstract】Objective To observe the changeable expressions of vascular endothelial growth factor (VEGF) and integrin β3 during the angiogenetic process of granulation tissue. Methods mRNA and protein of VEGF and integrin β3 in human normal subcutaneous tissue, proliferative granulation tissue and mature granulation tissue were observed by RT-PCR and immunohistochemistry staining. Results The expressions VEGF and integrin β3 were low in normal subcutaneous tissue and were much higher in proliferative granulation tissue. When the granulation tissue was mature, the expression was decreased again. Conclusion VEGF and integrin β3 are important regulating factors in ngiogenesis.
Objective To evaluate the effect of integrin-linked kinase (ILK) in the process of retinal neovascularization induced by vascular endothelial growth factor (VEGF). Methods The ILK activities of retinal choriodal endothelial cell line RF/6A were inhibited by LY294002 or siRNA knockdown. VEGF-induced changes of cell adhesion, proliferation, migration and endothelial cell tube-formation were measured then. The in-vivo effects of ILK were also assessed by intraperitoneal injection of LY294002 into an animal model of RNV. Results The cell adhesion measurements of control group, VEGF group, VEGF＋LY294002 group and VEGF＋siRNA group were 0.0726plusmn;0.01961, 0.1137plusmn;0.02631, 0.0837plusmn;0.01503 and 0.0853plusmn;0.02454 , respectively. The difference was statistically significant between VEGF group and control group（t =4.211，Plt;0.01）, and between (VEGF＋LY294002) group or (VEGF＋siRNA) group and control group (t =3.074, 2.91，Plt;0.01). The cell proliferation results of control group, VEGF group and VEGF＋LY294002 group were 0.4162plusmn;0.1392, 0.6412plusmn;0.2420, 0.4476plusmn;0.1834 , respectively. The difference was statistically significant between VEGF group and control group（t=2.608，Plt;0.05）, and between (VEGF＋LY294002) group and VEGF group（t=2.244，Plt;0.05）.The cell migration results of control group, VEGF group and VEGF＋LY294002 group were 83.66plusmn;30.283, 248plusmn;74.748, 138.5plusmn;38.167, respectively. The difference was statistically significant between VEGF group and control group（t=5.436，Plt;0.01）, and between (VEGF＋LY294002) group and VEGF group（t=3.682，Plt;0.01）. There was no obvious tube-formation after ILK activity was inhibited or knocked down. The non-perfusion areas were increased from （62798plusmn;16995.62）mu;m2 to （84722.65plusmn;10435.01）mu;m2 after intraperitoneal injection of LY294002 into animal model of RNV, the difference was statistically significant（t=3.476，Plt;0.01）. Conclusions ILK may play an important role in the process of VEGF-induced retinal neovascularization by regulating the cellular adhesion, proliferation, migration and tube-formation, as all those cellular functions were supressed obviously after the ILK activity was inhibited by LY294002 or the ILK expression was knocked down by siRNA.
Objective To review the role of integrin in nervous system injury and its repair, and to analyze the possible mechanisms. Methods Recent l iterature concerning integrin and its role in nervous system injury was reviewed and analyzed. Results Integrin and its related signall ing pathway were involved in nervous system injury, especially hypoxicischemic nervous injury, and their repair processes. Conclusion Intervention of integrin signall ing pathway would be a potential strategy to treat nervous system injury, especially hypoxic-ischemic nervous injury.
【Abstract】Objective To introduce the current research status, value and development future of Arg-Gly-Asp (RGD) peptides in diagnosis and treatment of neoplasms. Methods The current literatures on advances about RGD peptides in diagnosis and treatment of neoplasms were reviewed. Results RGD peptides, specificly recognizing and combining with integrin receptors, exist in extracellular matrix (ECM) of many kinds of organisms. After combining with integrin receptors, extrinsic RGD peptides can prevent tumor cells from adhering to ECM and migrating as the competitive inhibitor of intrinsic RGD peptides, suppress agiogenesis and induce tumor cells apoptosis, showing potential value of tumor specific imaging by targetal labelling neoplasms and treating tumors combining with other methods.Conclusion RGD peptides may be a new drug for diagnosis and treatment of neoplasms.
ObjectiveTo investigate the clinicopathological significance of integrin α5β1 expression and microvessel density(MVD) in gastric cancer(GC) and the correlation of MVD with integrin α5β1. MethodsThe expression of integrin α5β1 was detected by means of immunohistochemical staining (SP method) on paraffinembeded tissue specimens from 35 primary gastric carcinoma(PGC), 10 metastasic lymph node of gastric cancer and 8 chronic superficial gastritis (CSG). Vascular endothelial cells were stained immunohistochemically using antiCD34 monoclonal antibody to recognize microvessel(MV) in 35 cases of PGC and 8 CSG, MV was counted in 4 hot spot per slide under lightmicroscope (×400) and the average was defined as MVD. The results combined with clinicopathological parameters were analyzed statistically to characterize the role of integrin α5β1 and MVD in the progression of gastric cancer. ResultsIntegrin α5β1 expression and MVD in PGC were significantly higher than those in CSG respectively （t=3.32, P lt;0.01; t=2.30, Plt;0.05）; the expression of integrin α5β1 in PGC showed only a correlation with the invasion depth of tumor (t=2.29, Plt;0.05） while MVD showed all correlations with invasion depth,lymph node status and TNM stage （t=3.07, Plt;0.01; t=2.48, Plt;0.05; t=2.94,Plt;0.01）. Neither integrin α5β1expression nor MVD showed a relation with differential of PGC （t=0.15, Pgt;0.05; t=0.41, Pgt;0.05）. Integrin α5β1 was significantly overexpressed in lymph node metastatic cancer compared with that in corresponding PGC （t=2.45, Plt;0.05）; the difference of MVD showed no statistical significance among levels of integrin α5β1 expression in PGC （F =1.43,P＞0.05） and it showed no correlation with integrin α5β1 expression（r= 0.156, P=0.37）.Conclusion Overexpression of integrin α5β1 is present in GC and associates with the progression of tumor, implying that it may be viewed as the indicator of invasion and metastasis and the candidate target of gene therapy of gastric cancer. However, integrin α5β1 may not play an important role in the vascularization of GC.
Objective To evaluate the role for integrins in tumor angiogenesis. MethodsLiteratures in recent years were reviewed. ResultsIntegrins played an important role in tumor angiogenesis and integrins had a close relation to vascular growth factors. Conclusion Inhibitors of integrins will be a promising way to cure tumors.
Objective To provide theoretical evidence for clinical application of the epidermal stem cells after an investigation on changes of the epidermal stem cells during the survival process after the fullthickness skin autograft. Methods On the backs of 42 Wistar rats, orthotopic transplantation models (1.5 cm×1.5 cm) of the fullthickness skin autograft were made. According to the time of the specimen taking, at 1, 3, 5, 7, 14, 21 and 30 days after operation, the rats were randomly divided in 7 groups (Groups 1-7). Specimens taken in each group before operation were used as controls. At each time point, the gross observation was made on the transplanted skin flaps, from which the skin tissues were harvested at each time point before and after operation. The routine pathological and the immunohistochemical examinations were performed on the specimens, which were stained by HE and were observed for immunohistochemical changes and the changes in the cells positive for integrinβ-1 and p63. Results All the fullthickness skin autografts survived 3 days after operation except the skin autograft in 1 rat in both Group 5 and Group 6, which was infected around the transplanted skin flap. In Groups 1-4, cell edema, inflammatory cell infiltration, and increased fibrocytes were observed. In Groups 5-7, the maturity degree of the epithelial cells became higher and higher, and the fibrocyte proportion was lowered. In each group the cell positivity rate for integrin β1 was lower than the cell positivity rate for p63. The positive cells were arranged in disorder, distributed into the layers of the epidermis and gradually concentrated in the basal layer of the epidermis and the bulge of the folliculus pili. The positive cells were also found in the other layers of the epidermis.The positive cells were gradually decreased in number, and reached the lowest level in Group 2. There was a significant difference in the above variables in Groups 1,2,3,5,6 and 7 between before and after operations (P＜0.05). Conclusion During the survival process of the fullthickness skin autograft, the proportion of theepidermal stem cells is gradually decreased at first; Then, the proportion isgradually increased, even beyond the normal level; finally, the proportion is decreased again. The distribution of the epidermal stem cells appear in disorder, almost distributed in the layers of the epidermis; finally, the almost normal distribution can be found.
Objective To observe the expression of integrin αVβ3 in vascular endothelium cultured in vitro at different time points under different level of shear stress. Methods（1）We established a vascular culture system in vitro which could provide steady flow with different level of shear stress, and tested the flow stability when loading different level of shear stress. （2） A total of 50 rabbits were randomly divided into low shear stress group （5 dyn/cm2, n=25）and normal shear stress group（20 dyn/cm2, n=25）. Rabbits in each group were further randomly divided into five different time points as 2 h, 4 h, 8 h, 16 h and 24 h（n=5 at each time point）. The descending aorta of rabbits were harvested and cultured in the vascular culture system in vitro under different level of shear stress. The expression sites and intensity of αVβ3-Integrin in vascular endothelium were examined at 5 different time points in both groups by immunohistochemical staining. Results The vascular culture system in vitro was stable in providing laminar flow with different level of shear stress required for the experiment. Vascular endothelium expressions of αVβ3-Integrin in the low shear stress group were in high level at all the 5 time points and reached its summit at 16 h, when the mean optical density（MOD）value was （1.995±0.194）×10-2. In the normal shear stress group, the MOD value decreased time-dependently at the 5 time points. The MOD values at 2 h （0.059±0.005）×10-2 and 4 h（0. 049±0.002）×10-2 were significantly higher than those at other time points （P＜ 0.05）. The αVβ3-Integrin MOD values of the low shear stress group were significantly higher than those of the normal shear stress group at all the 5 respective time points （P=0.000）. Conclusion Low shear stress can significantly promote the expression of αVβ3-Integrin while normal shear stress decreases the expression of αVβ3-Integrin in vascular endothelium cultured in vitro.
ObjectiveTo investigate the value of integrin αvβ3 targeted microPET/CT imaging with 68Ga-NODAGA-RGD2 as radiotracer for the detection of osteosarcoma and theranostics of osteosarcoma lung metastasis.MethodsThe 68Ga-NODAGA-RGD2 and 177Lu-NODAGA-RGD2 were prepared via one-step method and their stability and integrin αvβ3 binding specificity were investigated in vitro. Forty-one nude mice were injected with human MG63 osteosarcoma to established the animal model bearing subcutaneous osteosarcoma (n=21), osteosarcoma in tibia (n=5), and osteosarcoma pulmonary metastatic (n=15). The microPET-CT imaging was carried out in 3 animal models at 1 hour after tail vein injection of 68Ga-NODAGA-RGD2. Biodistribution study of 68Ga-NODAGA-RGD2 was performed in animal model bearing subcutaneous osteosarcoma at 10, 60, and 120 minutes. The animal model bearing pulmonary metastatic osteosarcoma was injected with 177Lu-NODAGA-RGD2 at 7 weeks after model establishment to observe the therapeutic effect of pulmonary metastatic osteosarcoma. Histological and immunohistochemistry examinations were also done to confirm the establishment of animal model and integrin β3 expression in animal models bearing subcutaneous osteosarcoma and bearing pulmonary metastatic osteosarcoma.Results68Ga-NODAGA-RGD2 and 177Lu-NODAGA-RGD2 had good stability in vitro with the 50% inhibitory concentration value of (5.0±1.1) and (6.5±0.8) nmol/L, respectively. The radiochemical purity of 68Ga-NODAGA-RGD2 at 1, 4, and 8 hours was 98.5%±0.3%, 98.3%±0.5%, and 97.9%±0.4%; while the radiochemical purity of 177Lu-NODAGA-RGD2 at 1, 7, and 14 days was 99.3%±0.7%, 98.7%±1.2%, and 96.0%±2.8%. 68Ga-NODAGA-RGD2 microPET-CT showed that the accumulation of 68Ga-NODAGA-RGD2 in animal models bearing subcutaneous osteosarcoma and osteosarcoma in tibia and in lung metastasis as small as 1-2 mm in diameter of animal model bearing pulmonary metastatic osteosarcoma. Biodistribution study of 68Ga-NODAGA-RGD2 in animal model bearing subcutaneous osteosarcoma revealed rapid clearance from blood with tumor peak uptake of (3.85±0.84) %ID/g at 120 minutes. The distribution of 177Lu-NODAGA-RGD2 in lung metastasis was similar with 68Ga-NODAGA-RGD2. The number and size of osteosarcoma metastasis decreased at 2 weeks after 177Lu-NODAGA-RGD2 administration and integrin targeting specificity was confirmed by pathology examination.Conclusion68Ga-NODAGA-RGD2 was potential for positive imaging and early detection of osteosarcoma and metastasis. Targeted radiotherapy with 177Lu-NODAGA-RGD2 was one potential alternative for osteosarcoma lung metastasis.