Objective To study the effect of knockdown of signal transducer and activator of transcription 3 (STAT3) expression by short hairpin RNA (shRNA) on proliferation, apoptosis and invasion of human gastric cancer cell line MKN-45 in vitro . Methods Specific shRNA plasmids to STAT3 were constructed, and then transfected into MKN-45 cells by lipofectamine methods. Cells were divided into three groups: control group, psiRNA-H1 transfected group as negative group and psiRNA-H1/STAT3 transfected group. Semi-quantitative RT-PCR and Western blotting were used to detect the expression of STAT3 mRNA and protein, respectively. Proliferation and apoptosis of the transfected cells were observed by methyl thiazolyl tetrazolium (MTT) method and flow cytometry (FCM), respectively. The invasion of the transfected MKN-45 cells was measured by Boyden chamber. Results Compared with the negative control cells, semi-quantitative RT-PCR and Western blotting showed that the expressions of STAT3 mRNA and protein were down-regulated in the psiRNA-H1/STAT3 transfected group ( P ＜ 0.05) . The subcloned recombinant plasmid expressing shRNA effectively inhibited MKN-45 cell growth and proliferation while empty plasmid had no such specific effect. Cell apoptosis rate increased significantly in psiRNA-H1/STAT3 transfected group （ P ＜ 0.01）, and the invasion of MKN-45 cells was efficiently inhabited in psiRNA-H1/STAT3 transfected group as compared with control group and psiRNA-H1 transfected group( P ＜ 0.01).Conclusion Recombinant plasmid psiRNA-H1/STAT3 shRNA significantly inhibits the proliferation and invasion of MKN-45 cells and promotes their apoptosis.
Objective To be expressed human vascular endothelial growth factor (VEGF) recombinant protein in Escherichia Coli in high level. Methods VEGF was amplified from human fetal brain cDNA library, the amplified fragment was inserted into M13mP18 and confirmed to be VEGF165cDNA by restriction mapping and DNA sequencing, then it was combined with an expression vector PRL621. This recombinant plasmid overexpressed a 20kd recombinant protein in E.Coli(TG1), the protein was isolated and purifed from E.Coli, and initially renatured. Results The overexpressed recombinant protein was 35% of the total cell protein, the sequence of its first 15-N terminal amino acid was identrical to that of the human natural VEGF protein, Chorioallantoic membrane(CAM) assay showed that the rhVEGF promated new capillary vessels formation. Conclusion The genetic engineering Escherichia Coli can express human vascular endothelial growth factor in high level.
The expression and rearrangement of bcl-2 gene in 64 cases with colorectal carcinoma were studied by immunohistochemical technique and semi-nest PCR respectively. The results showed the abnormal changes of the expression and rearrangement of bcl-2 gene had emerged in the early stage of colorectal carcinoma. The tumors with the expression of bcl-2 were associated with a higher incidence of metastasis to lymphatic node. The rearragement of bcl-2 was significantly higher in late-stage than that in early-stage. These suggest that bcl-2 gene involves in the regulation of the development of colorectal carcinoma. The state of the changes of bcl-2 gene in colorectal carcinoma may predict the therapeutic effect and prognosis of colorectal carcinoma.
To explore the expression of Wnt-1 during the process of inducing neural stem cells (NSCs) into neurons by using all-trans-retinoic acid (ATRA) in vitro and the effect of Wnt-1 on NSCs differentiation. Methods NSCs isolated from cerebral cortex of SD rat embryo (12-16 days’ gestation) were cultured. The concentration of cells at passage 3 were adjusted to 1 × 106 cells /mL and treated with ATRA at 0.5, 1.0, 5.0 and 10.0 μmol/L, respectively. Differentiation ratio of NSCsinto neurons in each group was detected by double-labelling immunofluorescence technique and flow cytometry, and 1.0 μmol/ L was selected as the best concentration for ATRA to promote NSCs differentiation. In experimental group, NSCs at passage 3 were cultured with ATRA at 1.0 μmol/L in vitro, and expression of Wnt-1 was detected by immunocytochemistry staining, realtime flurescent quantitive PCR and Western blot at 3, 5, 7 and 9 days after culture, respectively. The cells at passage 3 receiving no ATRA served as control group. Results Immunocytochemistry staining: in the control group, there was l ittle Wnt-1 protein expression; in the experimental group, peak expression of Wnt-1 and numerous positive cells occurred at 3 days after culture, the positive expression of Wnt-1 was still evident at 5 days after culture, and there was significant difference between two groups in integrated absorbance (IA) value at 3 and 5 days after culture(P lt; 0.05), obvious decrease of positive expression of Wnt-1 was evident, and no significant difference was evident between two groups in IA value at 7 and 9 days (P gt; 0.05). Real-time fluorescence quantitative PCR: the relative expression of Wnt-1 mRNA in the control group was 0.021 7 ± 0.072 1; the relative expression of Wnt-1 mRNA in the experimental group at 3, 5, 7 and 9 days was 0.512 2 ± 0.280 0, 0.216 4 ± 0.887 0, 0.038 5 ± 0.299 4 and 0.035 5 ± 0.309 5, respectively, indicating the value decreased over time, and there were significant difference between two groups at 3 and 5 days (P lt; 0.05), and no significant difference at 7 and 9 days (P gt; 0.05) . Western blot detection: specific and visible staining band was noted; in the control group, Wnt-1 protein expression was 0.005 1 ± 0.558 3; in the experimental group, Wnt-1 protein expression at 3, 5, 7 and 9 days was 0.451 7 ± 0.071 3, 0.311 7 ± 0.080 5, 0.007 3 ± 0.052 7 and 0.004 7 ± 0.931 4, respectively, suggesting the value decreased over time; there were significant differences between two groups at 3 and 5 days (P lt; 0.05), and no significant differences at 7 and 9 days (P gt; 0.05). Conclusion With the induction of ATRA at 1.0 μmol/L, Wnt-1 and NSCs differentiation in early stage are positively correlated. Its possible mechanism may rely on the activation of such signals as classic Wnt-1 signal pathway, indicating Wnt-1 relates to the differentation of NSCs into neurons.
Objective To investigate the expression levels of osteoprotegerin (OPG) and receptor activator of NF-κB l igand (RANKL) mRNAs in bone tissues of the femoral head of the patients suffering glucocorticoid-induced osteonecrosisof the femoral head (ONFH), and to discuss the relationship between OPG/RANKL and ONFH. Methods Between March2007 and March 2008, bone tissues of the femoral head were collected as the experimental material from 35 patients suffering ONFH (experimental group) and from 21 patients suffering fracture of femoral neck (control group). The ratio of men to women in both groups was 4 ∶ 3, whose age was 41-70 years old (55.34 on average in the experimental group and 55.33 on average in the control group). The experimental group received over 3 weeks’ glucocorticoid treatment or more than 1 week’ s high-dose glucocorticoid treatment in recent 2 years, while the control group never received more than 1 week’s hormone treatment. In the two groups, the microstructure of bone tissues of the femoral head was detected by HE staining and the bone tissue total RNA was extracted, and then the expression levels of OPG mRNA and RANKL mRNA were examined by realtime quantitative PCR (RTQ-PCR) for each sample. Results HE staining: bone trabeculae and bone units were replaced by interrupted bone fragments, which were surrounded by many inflammatory granulation tissues and few osteocytes were seen in bone lacunae in the experimental group. In the control group, bone trabeculae and bone units were made by complete lamellar bones which surrounded blood vessels and osteocytes were seen in lacunae. RTQ-PCR testing: in the experimental group, OPG mRNA and RANKL mRNA were 1.35 ± 0.42 and 4.36 ± 1.35, respectively, while in the control group they were 1.78 ± 0.63 and 3.49 ± 1.02, respectively. The expression level of OPG mRNA in the experimental group was significantly lower than that in the control group, and the expression level of RANKL mRNA of the former was significantly higher than the latter. The OPG mRNA/ RANKL mRNA ratio in the xperiment group (0.34 ± 0.16) was significantly lower than that in the control group (0.54 ± 0.20), and there was significant difference (P lt; 0.05). Conclusion The glucocorticoid-induced ONFH may be related to the expression levels of OPG mRNA/RANKL mRNA in bone tissues.
Objective To investigate the changes in the expression level of PDGF in the bone callus of rats with femoral fracture and brain injury to explore the effect of brain injury on the fracture heal ing and the related mechanism. Methods Sixty-four 12-week-old SD rats weighing (356 ± 25) g were randomly divided into 8 groups with 8 rats in each. The rats in groups A1, B1, C1 and D1 had a femoral fracture and a brain injury for 1, 2, 3 and 4 weeks, respectively; the rats in groups A2, B2, C2 and D2 had a mere fracture without a brain injury for 1, 2, 3 and 4 weeks, respectively. After the CR films were taken, the bone callus was obtained 1, 2, 3 and 4 weeks after operation, respectively. Then, the bone callus and its histology were examined by HE staining, the expressions and changes in the level of PDGF were examined by the immunohistochemical staining, and the level of PDGF mRNA was measured by in situ hybridization. Results The CR films showed that the callus formation in the A1-D1 groups was earl ier and greater than that in the A2-D2 groups at the same time point. The HE staining indicated that more fibroblasts and early-stage chondrocytes were found in group A1; some fibroblasts in the fracture interspace and few early-stage chondrocytes were found in group A2; some newly-formed trabecular bones were found at the end of the fracture in group B1; but no trabecular bone formation was found in group B2; woven bone formation and a few chondrocytes between trabecular bones in the fracture interspace were found in group C1; only a few trabecular bones in the fracture interspace were found in group C2；woven bones turned to lamellar bones in group D1；and more immature trabecular bones in the fracture interspace were found in group D2. The positive expression of PDGF and PDGF mRNA was b in the cytoplasms of fibroblasts, mesenchymal cells, vascular endothel ial cells, early-stage chondrocytes, osteoblasts and osteoclasts. The percentage of the positive cells for PDGF and PDGF mRNA in the callus was significantly higher in groups A1-D1 than in groups A2-D2 at the same time point (P lt; 0.05). Conclusion Brain injury can promote the fracture heal ing process, which is probably related to an increase in the expression level of PDGF after the brain injury.
Objective To explore the expression of the vascular cell adhesion molecule 1 (VCAM1) in the acellular dermal matrix grafting in pigs. Methods Experimental models were established with 15 Inbred Strain mini pigs, 6 full-thichness skin defect wounds, 6 cm × 6 cm in size, were produced on both-side backs of the each pig, and then the pigs were randomly divided into 3 groups. In Group A (n=5, control) the thin auto-skintransplantation alone was made; in Group B (n=5), the grafting was performed in the acellular allo-dermal matrix combined with the thin auto-skins; in Group C (n=5), the grafting was performed in the acellular xeno-dermal matrixcombined with the thin auto-skins. The areas of the wounds were measured and the survival condition of the grafted skins was observed at 3, 9, 21 and 30 days after the grafting. The histological samples were harvested from the grafting area at 3, 6, 9, 12, 21 and 30 days after the procedure. The flow cytometry was employed to analyze the changes in the VCAM1 level in the sample at different time points after the grafting. Results In the 3 groups, the transplanted skin base was easily separated at 3 days after transplantation; the areas of the wound healing accounted for 94%±12%，92%±9%, and 91%±11%, respectively, at 21 days; good wound healing was achieved at 30 days. At 9 and 12 days after transplantation, there was an evidentlyincreased level of the VCAM-1 expression in the tissue samples in the composite skin grafting groups. Compared with the control group, the difference was significant (Plt;0.05); however, the VCAM-1 expression at 3 days was not statistically different between the composite skin grafting groups and the control group after transplantation. In contrast, the level of the VCAM-1 expression was significantly higher at 6 days in the control group than in the composite skin grafting groups (Plt;0.05). The levels of the VCAM-1 expression were significantly lower at 30 days than at 3 days after transplantation in all the 3 groups (plt;0.01). Conclusion The highest level of the VCAM-1 expression can be delayed in the composite skin grafting when compared with that in the thin auto-skins alone, which implies that the VCAM-1 expression may be correlated with angiogenesis and composite skin survival. The VCAM-1 expression is not different between the acellular allo-dermal matrix composite skin grafting groups and the acellular xeno-dermal matrix group.
Objective To construct the recombined DNA pcDNA3.1-hBMP-2 and transfect into human marrow stromal stem cells (MSCs) in vitro, and to explore theeffects of transfection on cellular proliferation and expression of vascular endothelial growth factor (VEGF). Methods The expression of human bone morphogenetic protein 2(hBMP-2) in these cells after transfection was determined by in situ hybridization and immunohistochemical analysis and Western blot analysis. The changes of cell proliferation were observed by flow cytometry. The effects of BMP-2 gene transfection on expression of VEGF in the cells were analyzed by in situ hybridization of VEGF cDNA probe. Results Stable expressionof hBMP-2 in pcDNA3.1-hBMP-2 transfected MSCs was confirmed in the levels of mRNA and protein.Cellular proportion in S period increased, which indicated that the synthesis of cell DNA increased. The expression of VEGF in the cells increased obviously. Conclusion With the help of lipofectamine, the pcDNA3.1-hBMP-2 were transfected into human MSCs successfully. hBMP-2 plays an important role in promoting cellular proliferation and vascular generation during bone repair.
OBJECTIVE: To observe the protein expression of phosphorylated form of P38 mitogen-activated protein kinase(P38MAPK) and c-Jun in hypertrophic scar skin and to explore their influences on the formation and maturation of hypertrophic scar. METHODS: The expression intensity and distribution of phosphorylated form of P38MAPK and c-Jun were examined with immunohistochemistry and pathological methods in 16 cases of hypertrophic scar skin and 8 cases of normal skin. RESULTS: In normal skin, the positive signals of phosphorylated form of P38MAPK mostly distributed in basal lamina cells of epidermis, while c-Jun was mainly located in epidermal cells and endothelial cells. The positive cellular rates of two proteins were 21.3% +/- 3.6% and 33.4% +/- 3.5% respectively. In proliferative hypertrophic scar skin, the particles of phosphorylated P38MAPK and c-Jun were mainly located in epidermal cells and some fibroblasts. The positive cellular rates of two proteins were significantly elevated to 69.5% +/- 3.3% and 59.6% +/- 4.3% respectively (P lt; 0.01). In mature hypertrophic scar, the expression of these proteins decreased but was still higher than that of normal skin. CONCLUSION: The formation and maturation of hypertrophic scar might be associated with the alteration of phosphorylated P38MAPK and c-Jun protein expression in hypertrophic scar.
OBJECTIVE: To explore the expressive characteristics of epidermal growth factor (EGF) and its receptor (EGFR) in tissues of fetal and adult intestines. METHODS: The expression intensity and distribution of EGF and EGFR were detected with pathological and immunohistochemical methods in 6 specimens of adult (16-54 years) intestines and 18 specimens of fetal intestines with different gestational ages (13-31 weeks). RESULTS: Positive protein particles of EGF and EGFR could be detected in tissues of fetal and adult intestines. The protein expressions of EGF and EGFR were elevated progressively with the gestational age. EGF was mainly located in the cytoplasm and extracellular matrix of intestinal villus cells, endothelial cells and tunica serosa epithelial cells, while EGFR chiefly distributed in the cellular membrane of these cells. CONCLUSION: The endogenous EGF and EGFR might be involved in the intestinal development at embryonic stage, in the structural and functional maintenance at adult stage, and in the wound healing after injury.