| Objective: Establishing a model of periapical periodontitis in wild-type mice to study the expression of PLC?2 in experimental periapical tissues of mice.Methods: Twenty healthy 6-week-old C57 BL / 6L WT male mice were selected and their bilateral mandibular first molar pulp cavity were exposed to the oral environment and induced the formation of apical periodontitis.The mouse were randomly sacrificed at 0w,1w,2 w,3w and 4w and the lower jaws were isolated.After being histological processed,they were hematoxylin-eosin(HE)stained to observe the inflammation conditions in the pulp area.Expression of PLC?2 in pulp were analyzed by immunohistochemical staining.Enzyme-histochemical staining was used to detect the expression of osteoclasts in the apical inflammatory tissue.And the correlation between PLC?2 expression and osteoclast expression in the apical area.Results:1.Histological analysisAccording to the histological examination,there was almost no inflammatory cell infiltration in the periodontal tissue of the mandibular first molar in the normal control group(0 week);one week after the operation,there was a small area of inflammation in the periapical tissues as well as a small amount of periodontal ligament broaden,a small amount of neutrophils can be seen at this time;two weeks after operation,the infiltration of inflammatory cells gradually increased,mainly in neutrophils,lymphocytes and macrophages and appeareed alveolar bone absorption;three,four weeks after surgery,inflammatory cell infiltration further aggravate,mostly lymphocytes,alveolar bone resorption range continues to expand.2.Immnohistochemical analysisThe positive cells of PLC?2 were stained dark brown by immunohistochemical staining and expressed in the periapical periodontitis of mice from 0 week to 4 weeks and increased with the infiltration of inflammatory cells and the range of alveolar bone resorption.In normal control group(0 week),there was only a small amount of PLC?2 positive expression in periapical tissues.From one week to four weeks after operation,positive expression of PLC?2 was observed in the center and periphery of the periapical inflammatory area,mainly located in the lymphocytes,plasma cells and other cells in the nucleus,the cell membrane and cytoplasm are also part of the expression.At the1 st,2nd,3rd,4th week,the positive expression of PLC?2 also increased due to the gradual expansion of inflammatory cell infiltration.The positive cell counts were all significantly different(P <0.05).At the same time,the apical bone destruction of blood vessels surrounding and root bifurcation of PLC?2-positive expression also increased.3.The correlation analysis results of PLC?2 and osteoclast number.The results of TRAP staining showed that almost no osteoclasts were observed in periapical periodontal tissues of normal control group(0 week).One week after operation,a small amount of multinucleated osteoclasts were observed.,the osteoclast cytoplasm stained with TRAP was burnt red.;the number of osteoclasts continued to increase 2 weeks after operation;after 3 weeks,osteoclasts The number reached its peak;at 4 weeks postoperatively,a decrease in the number of osteoclasts was observed.Correlation analysis between TRAP positive cell count and PLC?2 positive cell count showed a significant correlation(r = 0.627,P <0.001).Conclusion:The expression of PLC?2 in the periapical inflammatory tissues of mice increased with the expansion of inflammatory infiltration,and was significantly correlated with the expression level of osteoclasts,which revealed that PLC?2 may be closely related to periapical inflammatory reaction and bone resorption. |
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