Experimental Research Of Oral And Maxillofacial Infections Caused By LPS And Determination Of Its Immune Inflammatory Factors

Background:Oral infections have long been neglected.The nerve blood vessels of the oral and maxillofacial area are present in the interstices of the honeycomb tissue,and pass through the gaps,and the infection is spread over the gaps in the near and far gaps to form a multigap infection.Patients with infection of oral and maxillofacial clearance slightly facial discomfort in the initial stage,and after the corresponding gap is accumulated,obvious inflammation reaction occurs,the skin is reddish,facial swelling,palpation heat,spontaneous pain and tenderness,and obvious undulations after the formation of abscess.It is mainly through odontogenic and adenogenic infections that lead to dental diseases,maxillofacial diseases,periodontal infections,or common ulcers.If you don’t have an effective treatment in the early stages,which causes an infection in the mandibular facial tissue,you’ll be able to develop an infection in the mandibular facial cellulitis,the mandible osteomyelitis,and even the systemic infection,and even the risk of life.Early inflammation activates immune cells and releases tumor necrosis factor alpha,initiating an anti-inflammatory response.Immune cells can develop inflammation or other immune regulation,depending on the signal received from the microenvironment.If an inflammatory signal is received,the infection will spread further systemically,and the systemic inflammatory response will release a large amount of tumor necrosis factor alpha(TNF-α),the granule enzyme,the interleukin 1(IL-1),the oxygen radical and the like,and the medium,causing the rapid apoptosis of the lymphocytes,dendritic cells,and neutrophil to delay apoptosis,resulting in immunosuppression.In the inflammatory response,TNF-α and interleukin 6(IL-6)is a typical inflammatory factors.Its increase promote that recruitment and aggregation of inflammatory cells and aggravate inflammatory response.Purpose:In vitro oral maxillofacial bacterial infection and immune response model were established by use bacterial lipopolysaccharide(LPS)stimulation to mouse connective tissue fibroblast L929 and mouse macrophage RAW264.7 to detect that expression of inflammatory factors at different points in time.LPS were infect with that position of the mandible corresponding to the posterior region of C57 BL / 6 mice,and establish an in vivo model of the bacterial infection in the oral cavity and maxillofacial bacteria,and detecting the expression of the inflammatory factor at a corresponding time point.Result:It was found from that result of cck-8 that L929 cells have a significant proliferation rate(P < 0.01)when LPS stimulate 24 h,and the concentration is less than 20 μg/ml.However,with the increase of concentration(30-50 μg/ml),the cell proliferation rate began to decline.The proliferation of cells tended to be stable when the concentration reached 50 μg/ml.RAW264.7 cell proliferation rate was significantly increased when the LPS stimulated for 24 h and the concentration was less than 50 μg/ml(P < 0.01).And more than 50 mu g/ml,the cell proliferation rate fall.QPCR experimental results showed that TNF-α,IL-1,IL-5,IL-6,IL-8,IL-33 mRNA expression increased significantly,and IL-10,IL-13,IL-23 expression decreased obviously.CXCL2,CXCL10,FOXO3,GDF15 expression significantly increased.The results of ELISA showed that the levels of IL-6 were 42.04pg/ mL and 45.52pg/m L,respectively,with the stimulation of 50 μg/mL LPS stimulation of 24 h and 48 h,and the secretion of IL-6 in L929 cells.RAW264.7 cell secretion of IL-6 content is 25.90 pg/ml,28.92 pg/ml.LPS of 100 μg/ml LPS was stimulated 24 h,48h,and the content of IL-6 contained in L929 cells was 18.97 pg/ml,21.29 pg/ml;The content of IL-6 in RAW264.7 cells was 16.90 pg/ml,18.21 pg/ml.In vivo experiments on the maxillofacial expression of LPS infected C57BL/6 mice,when the LPS was injected into 4h,the mice showed slow movement and slow response.After 72 h,the average weight of the experimental group decreased by 4±1 g,and the mice showed a decrease in ingestion,and the fecal adhesion remained near the anus,and there was no obvious resistance to the hanging tail,and the behavior was slow.Fibrous connective tissue from infected area,salivary gland tissue,muscle tissue pathological change,a large number of inflammatory cells infiltration,the inflammation of the corresponding tissue atrophy,liquefaction,degeneration,necrosis and fibrosis.ELISA results showed that serum IL-6 levels increased from 0.419444pg/ml to 62.62851pg/ml(5μg/ml)and TNF-α levels increased from 0.322800pg/ml to 9.520406pg/ml,while LPS When the concentration was 15 μg/ml,the contents of IL-6 and TNF-α were 24.8694 pg/ml and 7.56178 pg/ml(10 μg/ml),which were decreased by 37.75914 pg/ml and 1.928626 pg/ml,respectively.Conclusion:1.L929 cells were stimulated with different concentrations of LPS for a short period of time(≤ 12 h)and the growth of L929 cells was inhibited continuously.2.LPS stimulation L929 cell 24 h,with the increase of concentration,cell proliferation rate rise gradually,when the concentration of LPS to 30 μg/ml,began to decline,and hence that LPS can cause cell growth,but high concentrations can inhibit the growth of cells.3.At the same time,the increase of LPS concentration had no significant effect on the proliferation of RAW cells.At the same concentration,LPS can promote RAW cell proliferation in a short time(≤12h).4.LPS stimulated 24 h,and the concentration was greater than 50 μg/ml,and the cell proliferation rate decreased,indicating that the stimulation of LPS for a long time could lead to the obvious growth of RAW cells,while high concentration had inhibitory effect on cell growth.5.LPS stimulation of L929 and RAW264.7 cells can induce inflammatory response in cells,and the expression of related inflammatory factors and chemokine factors increased,demonstrating the successful establishment of an external model of oral and maxillofacial infection.6.LPS infected C57 BL / 6 mice can cause inflammation occurs in oral and maxillofacial tissue that fibrous connective tissue,salivary gland,muscle tissue organization occurred liquefaction degeneration,fibrosis,atrophy,necrosis and other pathological changes.However,the expression of IL-6 and TNF-α in serum also increased significantly,and the model of oral and maxillofacial infection was established successfully.