Effect of hypoxia on the expression of matrix metalloproteinase and tissue inhibitors of matrix metalloproteinase mRNA in human periodontal ligament fibroblasts in vitro / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of hypoxia on the expression of matrix metalloproteinase (MMP) and tissue inhibitors of matrix metalloproteinase (TIMP) in human periodontal ligament fibroblasts (HPDLF).</p><p><b>METHODS</b>HPDLF were cultured in α-minima essential medium (α-MEM) and subcultured at confluence. In the hypoxic groups, cells were incubated in a humidified atmosphere of 1%O(2), 5%CO(2), 94%N(2) at 37°C for 12, 24 and 48 h, respectively. In the normoxic control group, cells were incubated under normoxic conditions of 20%O(2), 5%CO(2), 75%N(2). The mRNA expression of MMP and TIMP was measured using reverse transcription-polymerase chain reaction (RT-PCR). The data was analyzed by Student's t test, one-way ANOVA and LSD test with SPSS 13.0 software package.</p><p><b>RESULTS</b>The expression of MMP-2, TIMP-1 and TIMP-2 mRNA in the hypoxia groups was higher than that in control. The expression of MMP-2 mRNA in hypoxic groups showed a significantly increasing trend. There was significant difference between the hypoxic group and the normoxic control group in the expression of MMP-2 mRNA in HPDLF (P < 0.01). The expression of TIMP-1, TIMP-2 mRNA in hypoxic groups of 12 h was momentarily increased. There was significant difference between the hypoxic 12 h group and the normoxic control group in the expression of TIMP-1, TIMP-2 mRNA in HPDLF (P < 0.05). However, with prolonged hypoxia time, the expression of TIMP-1, TIMP-2 mRNA in hypoxic groups showed a significantly declining trend, there were significant differences between the hypoxic 12, 24 and 48 h group and the normoxic control group in the expression of TIMP-2 mRNA in HPDLF (P < 0.05). The expression of MMP-1 mRNA in hypoxic groups of 12 h was momentarily decreased and then increased after 24 h of hypoxia. There were significant differences between the hypoxic 48 h group and the normoxic control group in the expression of MMP-1 mRNA in HPDLF (P < 0.05). There were significant differences between the hypoxic 12 h group and the normoxic control group in the ratio of MMP-1/TIMP-1 mRNA (P < 0.05). The ratio of MMP-2/TIMP-2 mRNA in the hypoxia group significantly increased compared with normoxic group. There were significant differences between the hypoxic group and the normoxic control group in the ratio of MMP-2/TIMP-2 mRNA (P < 0.05).</p><p><b>CONCLUSIONS</b>Hypoxia could change the expression of MMP and TIMP mRNA and other relevant growth factors and also lead to the imbalance of MMP-2/TIMP-2 mRNA expression. It is suggested that the imbalance of MMP-2/TIMP-2 expression may be closely correlated with the occurrence and development of periodontal disease and play an important role in the process of periodontal tissue destruction in periodontitis.</p>

Combination of EMPs and BMSCs in promoting regeneration of periodontal tissue / 上海第二医科大学学报

Objective To evaluate the feasibility of reconstructing horizontal periodontal bone defects by tissue engineering based on bone marrow stromal cells(BMSCs)as seed cells and enamel matrix proteins(EMPs)as growth factors. Methods Two healthy rhesus monkeys were selected, and BMSCs were isolated from iliac marrow and serial subcultivation was conducted. The cells of induced BMSCs at passage 3 were harvested and mixed with Bio-oss collagen. The models of horizontal periodontal bone defects were established surgically in each buccal side of the posterior teeth, and were divided into four groups (blank control group, material group, cells/material group and cells/material/EMPs group). The histological and Micro-CT observation were carried out 8 weeks later. Results In the blank control group, the defects were filled with fibrous connective tissue. There was newly-formed alveolar bone in the material group. In the cells/material group, periodontal regeneration could be observed, while the newly-formed cementum was irregular and less in quantity. In the cells/material/EMPs group, the amount of newly-formed alveolar bone was larger, and the newly-formed cementum was continuous and regular. Conclusion The tissue engineering technique of BMSCs as seed cells in combination with EMPs induction can significantly promote the regeneration of periodontal tissue.

The effect of bFGF on proliferation of periodontal fibroblast-like cells of dogs / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effects of basic fibroblast growth factor(bFGF) on proliferation of periodontal fibroblast-like cells in vivo.</p><p><b>METHODS</b>A U-shaped osseous defect was produced on the buccal side of the mesial root. Four posterior teeth were conducted in four quadrants. Each quadrant included 4 groups: control, bFGF, expanded polytetrafluoroethylene(ePTFE) membrane, bFGF + ePTFE. Each time the 4 teeth sites in one quadrant were operated weekly and each dog experienced 4 times of operations. Bromodeoxyuridine(BrdU) was injected 1 hour prior to sacrificing the dogs at 4 weeks after first surgery. Immunohistochemical method was applied to count the BrdU-labeled fibroblast-like cells.</p><p><b>RESULTS</b>The number of BrdU-labeled cells reached the maximum at the 2nd week among all groups and then, decreased with time. Both bFGF and bFGF + ePTFE treated group had significantly more BrdU+ cells than remained control or ePTFE groups (P < 0.05) at 1st, 2nd weeks after surgery.</p><p><b>CONCLUSION</b>2 weeks after periodontal surgery is active phase of proliferation of periodontal fibroblasts. bFGF enhances fibroblast proliferation in early periodontal wound healing, and in turn accelerate periodontal regeneration.</p>