Study On The Reshaping Of Ear Cartilage By Local Collagen Synthesis Mediated By Long-pulse 1064nm Nd:YAG Laser

Objective:The clinical incidence of ear deformity is relatively high,and the long-pulse 1064 nm Nd:YAG laser assisted shaping technology has been used clinically.Currently,it is believed that laser can promote the local collagen hyperplasia of cartilage and thus change its plasticity,but the molecular mechanism is still unclear.The purpose of this study is to preliminarily explore the molecular mechanism of laser action and provide better support for the clinical application of laser.Methods:New Zealand rabbits aged 3 months were used as experimental objects:1.The histological changes of rabbit ear cartilage after laser irradiation were observed by histopathological staining technique,and the changes of type Ⅱ collagen were analyzed.2.The rabbit ear cartilage tissues after irradiation and the control group were cut,and transcriptome RNA sequencing technology was used to determine the changes of related genes after irradiation;3.Primary rabbit ear chondrocytes were extracted,the cells were precipitated and irradiated by laser.CCK8 was used to detect cell activity and determine the optimal energy for in vitro irradiation.4.Based on the sequencing data,biogenic analysis and related literature reports were conducted to determine the role of IL-36 and MMP family molecules;5.qRT-PCR and ELISA were used to quantitatively detect IL-36α and MMP13,which were most down-regulated after in vitro irradiation.6.After the intervention of IL-36α and MMP 13 by siRNA,chondrocytes were irradiated by laser to observe the changes after irradiation;7.The downregulation of IL-36α and MMP13 after irradiation was verified in vivo by immunohistochemistry,qRT-PCR and ELISA.Results:1.After laser irradiation,the chondrocytes in the radiation belt of rabbit ear were elongated and the content of local collagen was increased.2.After irradiation,RNA sequencing found that 384 genes were up-regulated,141 genes were down-regulated,and IL-36 and MMP families were significantly down-regulated.3.CKK8 detection of irradiated cells showed that the activity of chondrocytes was upregulated after 50J/cm2 energy irradiation.4.Enrichment analysis and GSEA results showed that collagen decomposition process and IL-17 signaling pathway were significantly down-regulated;5.qRT-PCR and ELISA showed that IL-36α and MMP13 were most significantly down-regulated after irradiation.6.The expression of MMP13 was significantly down-regulated after the intervention of IL-36α by siRNA,and the expression of both was decreased simultaneously by laser irradiation.7.Immunohistochemistry,qRT-PCR and ELISA showed that local expressions of IL-36αand MMP13 were down-regulated after laser irradiation in rabbit ears.Conclusion:The shaping ability of rabbit ear cartilage at 3 months of age was improved after long-pulse 1064 nm Nd:YAG laser irradiation,which was related to the increase of local type Ⅱ collagen content.After laser irradiation,the expression of IL-36α-MMP13 axis was down-regulated,and the expression of Col22a1 was upregulated,resulting in the structural changes of cartilage matrix,the increase of local collagen content,and the improvement of cartilage shaping ability.