Expression Of Autophagy-associated Protein LC3Av1 And LC3B In Induced Rat Pulpitis And Typical Dental Pulp Diseases Clinical Report

Objective: To establish the model of pulpitis in rats and investigate the expression of LC3Av1 and LC3 B in induced rat pulpitis.Methods: In twenty-four 8-week-old SD rats,pulps of left mandibular first molars were exposed with LPS(5 ?g/?L)cotton ball,then the cavities were filled with glass ionomer.Six rats were selected to be the blank control group.The rats were randomly sacrificed at 6 h,12 h,24 h and 48 h 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 LC3Av1 and LC3 B in pulp were analyzed by immunohistochemical staining.Results:1.Histological analysis According to the histological examination,we confirmed that pulpitis were suscessfully induced by enclosing Escherichia coli LPS.At 6h after operation,a small amount of neutrophil infiltration was found below the pulp point,and there was a slight disorder ofodontoblasts;At 12 h after operation,a large number of neutrophil infiltration was found below the pulp point,manifested as acute inflammatory exudate response;At 24 h after operation,the inflammatory reaction of the pulp was further aggravated,and some of the coronal pulp degeneration and necrosis were observed;At 48 h after operation,the necrotic area in the center of penetration of the pulp was spread to the root of the pulp,and the vascular dilation and hyperemia were significant.2.Immnohistochemical analysis A small amount of LC3Av1 and LC3 B expressed in normal dental pulp tissues.The expression of LC3Av1 and LC3 B in the experimental group were increased,and mainly expressed in cytoplasm and cell membrane.At 6h after operation,the expression of LC3Av1 and LC3 B could be detected in the odontoblast layer near the perforation;At 12 h after operation,a large number of LC3Av1 and LC3 B positive cells were found in the odontoblast layer and the multicellular layer in the whole pulp tissues;At 24 h and 48 h after operation,a large number of LC3Av1 positive cells were found in the odontoblast layer and the multicellular layer in the whole pulp tissue,but the number of LC3 B positive cells was significantly decreased.The expression of LC3Av1 increased at 6h after operation and reached peak value at 12 h.The expression of LC3Av1 were higher in pulpitis than those in normal dental pulp(P<0.01),and the expression of LC3 B were higher in pulpitis at 6,12 hours compared with others(P<0.05).Conclusion:Expression of LC3Av1 and LC3 B in dental pulp increased with the development of inflammation,which suggested that autophagy may be associated with the development of pulpitis.