| Background: Pulpitis occurs in dental pulp tissue and produces significant pain,which affects the work,relaxation and dialy life of patients.In clinic,a large number of doctors at home and abroad choose root canal therapy for the treatment of pulpitis,but it may increase the risk of tooth fracture in the long-term run.Therefore,looking for new drug therapy may become a new research direction to inhibit pulpal inflammation and preserve living pulp.Tripterine,a traditional Chinese medicine,is a natural active ingredient with antitumor,anti-inflammatory and immunosuppressive effects.At present,studies have shown that tripterine has a significant role in inhibiting inflammation,but whether tripterine can also inhibit pulpitis has not been reported.Objective: To determine the construction method of acute pulpitis model in SD rats and to explore whether tripterine can inhibit pulpitis.Method:1.The rats were anesthetized and fixed in supine position.The left and right maxillary first molars of rats were drilled without water spray.When the drilling stopped at the red penetration point,sharp probes were used to pierce the top of the pulp chamber.After hemostasis with normal saline cotton ball,place LPS small cotton ball,remove the cotton ball for 30 min and wipe dry the medullary opening.After 1,3 and 5days,the maxillary first and second molars were extracted and the inflammation of dental pulp was determined by HE staining.At the same time,and the expression level of TNF-α,IL-1β in dental pulp was detected by q RT-PCR.2.After successfully establishing the rat model of pulpitis,direct pulp capping is used for treatment.Sixteen rats are treated with direct pulp capping immediately after the model construction of maxillary first and second molars.The rats are randomly divided into 4 groups,with 4 rats in each group: model group,calcium hydroxide treatment group,tripterine treatment group and calcium hydroxide+tripterine mixed drug treatment group.After direct pulp capping,the rats are temporarily sealed with glass ionomer cement.3.days later,the rats are killed,the maxillary first and second molars are extracted,and some isolated teeth are randomly selected for HE staining to determine the inflammation in dental pulp tissue.The dental pulp status of each group is evaluated according to the semi quantitative histological scoring standard and the remaining teeth are divided into two groups.In group 1,the RNA in tooth tissue is extracted and the expression level of TNF-α,IL-1βin dental pulp is detected by q RT-PCR.The other group extracts the protein from tooth tissue and Western Blot is used to detect the expression level of NF-κB and NF-κB p65.Result:1.Through the accumulation of food residues,disordered arrangement of dental pulp cells and increased inflammatory cells in the pulp tissue after LPS cotton ball was directly placed after pulpotomy,it is proved that the acute pulpitis model of SD rats has been successfully constructed.The q RT-PCR results showed the higher expression levels of the inflammatory factor TNF-α and IL-1β in the model compared with the control group.2.In the HE staining results of dental pulp tissue after direct pulp capping,the pulp angle was used as the observation field.The arrangement of dental pulp cells in the model group was disordered,with severe inflammatory cell infiltration and tissue necrosis.The calcium hydroxide group and tripterine group had moderate inflammatory cell infiltration,accompanied by vasodilation and vacuole like tissue.The calcium hydroxide and tripterine group had mild inflammatory cell infiltration without obvious tissue congestion and necrosis.The semi quantitative histological score showed that the score of the mixed drug group was significantly lower than that of the model group,and the difference was statistically significant（P < 0.05）.The q RT-PCR results showed that the expression level of inflammatory factor TNF-α and IL-1β was significantly decreased in each treatment group after direct pulp capping,the difference was statistically significant（P < 0.05）.The Western Blot test results showed that the protein content of NF-κ B and NF-κ B p65 in the mixed drug group was reduced compared with the molded group,and the difference was statistically significant（P < 0.05）.Conclusion:1.Pulpotomy + LPS cotton ball placement can successfully establish the acute pulpitis model of SD rats.2.Tripterine can inhibit experimental pulpitis in rats.And its mechanism may be related to the decrease of NF-κB and NF-κB p65 by tripterine. |
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