Objective To investigate the effect of leptin on fibroblast proliferation and collagen synthesis as to elucidate that fibroblasts play a role in leptin’s effect on wound healing. Methods Purified dermal fibroblasts were derived from sucking wistar rat skin and exposedto leptin at concentration of 0, 10, 50, 100, 200, and 400 ng/ml. The survived fibroblasts were assessed by the colorimetric thiazolyl blue (MTT) assay. Replication of fibroblast was quantified by the incorporation of 3H-thymidine. Collagen synthesis of fibroblast cell was measured by the incorporation of 3H-proline into collagenasesensitive protein. Results The absorption of fibroblast exposed to leptin at concentration of 200 and 400 ng/ml 0.082±0.013, 0.091±0.018 was higher than that of control group 0.063±0.010, P＜0.05. The incorporations of 3H-thymidine of fibroblast exposed to leptin at concentration of 200 and 400 ng/ml 379±101 cpm,326±33 cpm were significantly higher than those of control group 219±56 cpm, P＜0.05. The incorporations of 3H-proline of fibroblast exposed to leptin at concentration of 200 and 400 ng/ml 911±55 cpm, 1 072±259 cpm were significantly higher than that of control group 679±176 cpm, P＜0.05. Conclusion Leptin can promote rat cutaneous fibroblast proliferation and collagen synthesis in vitro. This suggests that cutaneous fibroblast plays a role in leptin’s promoting skin wound healing and it may be one of the main mechanisms by which leptin enhances skin wound healing.
OBJECTIVE: To investigate the biological characteristics of continuously subcultured human embryonic skeletal myoblasts, and choose the optimal seeding cells for muscle tissue engineering. METHODS: Human embryonic skeletal myoblasts were subcultured in vitro. The growth curve, rate of myotube formation(RMF) were used to evaluate the proliferative and differentiation ability of myoblasts, and to investigate the influence of fibroblasts contamination on myoblasts. RESULTS: The beginning 6 passages of myoblasts showed b proliferative and differentiation ability. From the 8th to 20th passage, the rate of fibroblasts contamination was increased, it mainly showed the growth characteristics of fibroblasts with increased proliferation and low differentiation. After subcultured to the 20th passage, the degeneration of myoblasts was obvious. CONCLUSION: The myoblasts within 6 passages should be used as the seeding cells of muscle tissue engineering because of b proliferative ability and high rate of myotube formation.
OBJECTIVE: To investigate the effects of dexamethasone on the proliferation and differentiation of bone marrow stromal cells(MSC). METHODS: MSC were isolated and cultured in vitro. After treatment with different concentrations of dexamethasone (0, 10-10, 10-9, 10-8, 10-7 and 10-6 mol/L), the proliferation and alkaline phosphatase (ALP) activity of MSC were measured to evaluate the effect of dexamethasone on the biological characteristics of MSC. RESULTS: Dexamethasone inhibited cell proliferation. With the increase of concentration of dexamethasone, the effect was enhanced, which was more significant when the concentration of dexamethasone was over 10-8 mol/L. At the same time, dexamethasone promoted the activity of ALP. This effect was enhanced with the increase of concentration of dexamethasone, but the alteration was small when the concentration of dexamethasone was over 10-8 mol/L. The effects increased with the time. The activity of ALP was enhanced 2 to 4 times with the dexamethasone for 6 days. CONCLUSION: Dexamethasone inhabit the proliferation of MSC, while induce them to differentiate into osteoblasts. The appropriate concentration of dexamethasone was 10-8 mol/L.
Objective To investigate the role of DNA methylation on regulation of cell apoptosis and proliferation in ischemia-reperfusion of small intestine. Methods Thirty-five male Wistar rats were randomly divided into normal group， sham operation group， and ischemia-reperfusion group. The apoptotic cell was assessed by TUNEL and electron microscopy and the expression of Ki-67 was examined by immunohistochemistry in the small intestinal parts （villi epithe-lium， crypt epithelium， and lamina propria mucosa of small intestine）. The DNA methylation was detected by DNA histo-endonuclease-linked detection of methylated DNA sites. Results ①The apoptotic positive cells increased at 3 h， 6 h，and 12 h after ischemia-reperfusion in the villi epithelium， crypt epithelium， and lamina propria mucosa of small intestine as compared with the normal group and sham operation group （P＜0.01）；Moreover， the apoptotic cells in the lamina propria mucosa of small intestine were identified as T cells by electron microscopy. ②The expressions of Ki-67 markedly increased at 3 h， 6 h， 12 h， and 24 h after ischemia-reperfusion in the villi epithelium cells as compared with the normal group and sham operation group （P＜0.01）. ③The weak expression of DNA methylation was found in the villi epith-elium and crypt epithelium in the normal group and sham operation group， the b expression was examined in the crypt epithelium cells nearby stem cell site in the ischemia-reperfusion of small intestine， the change of expression was gradually weak from crypt epithelium to villi epithelium. Conclusion This initial results indicate that the DNA methyl-ation in the ischemia-reperfusion of small intestine might regulate cell apoptosis and proliferation.
OBJECTIVE: To analysis the proliferation properties and telomerase activity of human embryonic tendon cells transformed by ptsA58H plasmid cultured in vitro continuously. METHODS: The 40th, 70th, and 75th passages of transformed human embryonic tendon cells (THETC) were adopted. The collagen secretion of THETC was detected by immunohistochemical methods, the growth curve of different passages of THETC was compared, and chromosome karyotype was analyzed. Total RNA of THETC were extracted to detect human telomerase reverse transcriptase (hTERT) mRNA expression by RT-PCR technique. RESULTS: When THETC were subcultured to 70 passages, the morphological characteristics of cells changed and began replicative senescence. THETC still could secret type I collagen normally. The chromosome of THETC was heteroploid (2n = 94). There were no hTERT mRNA expression. CONCLUSION: SV40 transfection can not make human embryonic tendon cells immortalization, on the other hand, human embryonic tendon cells transformed by ptsA58H plasmid has no tendency of malignant transformation.
Objective To explore the effect of the platelet-rich plasma (PRP) on proliferation and osteogenic differentiation of the bone marrow mesenchymal stem cells (MSCs) in China goat in vitro. Methods MSCs from the bone marrow of China goat were cultured. The third passage of MSCs were treated with PRP in the PRP group (the experimental group), but the cells were cultured with only the fetal calf serum (FCS) in the FCS group (the control group). The morphology and proliferation of the cells were observed by an inverted phase contrast microscope. The effect of PRP on proliferation of MSCs was examined by the MTT assay at 2,4,6 and 8 days. Furthermore, MSCs were cultured withdexamethasone（DEX）or PRP; alkaline phosphatase (ALP) and the calcium stainingwere used to evaluate the effect of DEX or PRP on osteogenic differatiation of MSCs at 18 days. The results from the PRP group were compared with those from the FCS group. Results The time for the MSCs confluence in the PRP group was earlier than that in the FCS group when observed under the inverted phase contrast microscope. The MTT assay showed that at 2, 4, 6 and 8 days the mean absorbance values were 0.252±0.026, 0.747±0.042, 1.173±0.067, and 1.242±0.056 in the PRP group, but 0.137±0.019, 0.436±0.052, 0.939±0.036, and 1.105±0.070 in the FCS group. The mean absorbance value was significantly higher in the PRP group than in the FCS group at each observation time (P＜0.01). Compared with the FCS group, the positive-ALP cells and the calcium deposition were decreased in the PRP group; however, DEX could increase boththe number of the positiveALP cells and the calcium deposition. Conclusion The PRP can promote proliferation of the MSCs of China goats in vitro but inhibit osteogenic differentiation.
OBJECTIVE: To determine the influence of basic fibroblast growth factor (bFGF) on endothelial cell (EC) proliferation in vitro and its possible mechanisms, and to examine the effect of both TNP-470 and dexamethasone (Dex) on the EC proliferation induced by bFGF. METHODS: Human umbilical vein endothelial cells were cultured and the proliferation of EC was quantified by a colorimetric assay using MTT reagent. The expression of nuclear factor-kappa B (NF-kappa B) and ki-67 was detected with SABC immunohistochemical method. RESULTS: bFGF stimulated the EC proliferation and enhanced the expression of NF-kappa B and ki-67 in nucleus; TNP-470 and Dex suppressed EC proliferation induced by bFGF, and reduced the expression of NF-kappa B and ki-67 in nucleus. CONCLUSION: The above results indicate that the possible mechanisms of EC proliferation stimulated by bFGF come from that bFGF can activate NF-kappa B to promote the synthesis of DNA and EC mitosis. TNP-470 and Dex inhibited EC proliferation stimulated by bFGF by inhibiting NF-kappa B.
【Abstract】Objective To explore the clinical significance of β-catenin expression in pancreatic carcinoma.Methods The immunohistochemical staining was performed to detect the expression of β-catenin in the specimens of 46 patients with pancreatic carcinoma and the results were statistically analyzed.Results The abnormal expression rate on the membrane was 54.3%, the poorer the differentiation, the higher the abnormal expression rate. The levels of the cases in whom metastasis occurred were much higher than those without metastasis. The abnormal cytoplasm expression rate was 21.7%,which had not significant correlation with the clinical indexes, such as staging, tumor size, grading and metastasis. In 23 patients who accepted intervention chemotherapy before operation, the cytoplasm expression rate in those with tumor mass smaller was 0, which was evidently lower than that of those without tumor mass change (33.3%). Moreover, the abnormal membrane and cytoplasm expression rates had remarkable concordance (63.0%).Conclusion The abnormal membrane expression of β-catenin may accelerate metastasis, and the abnormal expression of β-catenin in cytoplasm may result in cell proliferation.
ObjectiveTo explore the effects of exogenous estrogen receptor β1 (ERβ1) gene on the expression of human telomerase reverse transcriptase (hTERT) as well as the changes of proliferation ability in MDA-MB-231 cell line by transfecting recombinant eukaryotic expressing vector containing ERβ1 cDNA into human breast cancer MDA-MB-231 cell. MethodsRecombinant eukaryotic expressing vector containing ERβ1 cDNA was transfected into human breast cancer MDA-MB-231 cell by using cationic liposome as transfecting agent (acted as pcDNA3.1ERβ1 transfection group), empty vector group and non-transfection group acted as controls. The expression levels in both the mRNA and protein of both the ERβ1 and hTERT were tested by real-time PCR and Western blot, respectively. The change of proliferation ability in MDA-MB-231 cell was displayed by cell growth curve, and the change of cell apoptosis was detected by flow cytometry. ResultsThe expression level of ERβ1 mRNA in the pcDNA3.1-ERβ1 transfection group (0.449±0.077) significantly increased as compared with the nontransfection group (0.153±0.035) or the empty vector group (0.160±0.020), P=0.001 or P=0.000. The expression level of ERβ1 protein in the pcDNA3.1-ERβ1 transfection group (0.847±0.065) significantly increased as compared with the non-transfection group (0.356±0.050) or the empty vector group (0.390±0.030), P=0.001 or P=0.000. The expression level of hTERT mRNA in the pcDNA3.1-ERβ1 transfection group (0.127±0.020) significantly decreased as compared with the non-transfection group (0.283±0.025) or the empty vector group (0.283±0.049), P=0.001 or P=0.002. The expression level of hTERT protein in the pcDNA3.1-ERβ1 transfection group (0.147±0.023) significantly decreased as compared with the non-transfection group (0.783±0.025) or the empty vector group (0.802±0.019), P=0.001 or P=0.002. The rate of cell apoptosis in the pcDNA3.1-ERβ1 transfection group 〔(6.15±0.94)%〕 was higher than that in the non-transfection group 〔(1.41±0.42)%〕， P=0.001. Cell proliferation curve showed that proliferation ability significantly decreased in the pcDNA3.1-ERβ1 transfected groups as compared with the non-transfection group (Plt;0.05). ConclusionERβ1 could inhibit cell growth of human breast cancer MDA-MB-231 cell by down-regulating the expression of hTERT.
OBJECTIVE: To investigate the effects of bone morphogenetic protein (BMP) on the proliferation and collagen synthesis of skeletal muscle satellite cells. METHODS: Skeletal muscle satellite cells were harvested and cultured in vitro. The 0 ng/ml, 50 ng/ml, 100 ng/ml, 500 ng/ml, and 1000 ng/ml BMP were used to induce skeletal muscle satellite cells for 48 hours. Cell proliferation, rate of myotube formation and collagen-1 synthesis were measured. RESULTS: BMP promoted cell proliferation and reduced the rate of myotube formation. Collagen synthesis increased when skeletal muscle satellite cells were induced with more than 500 ng/ml BMP. And the higher the concentration of BMP was, the ber this effect became. CONCLUSION: BMP can enhance the proliferation of skeletal muscle satellite cells and change their differentiation from myoblasts to osteoblasts.
