A Study On The Effect Of Stem Cells From Human Exfoliated Deciduous Teeth And The Derivatives On The Prognosis Of Condylar Cartilage Degeneration During Rat Temporomandibular Osteoarthritis

Temporomandibular disorder is the fourth most common disease in the oral field,and its severe manifestation-temporomandibular joint osteoarthritis(TMJ OA)is a degenerative joint disease characterized by progressive cartilage degeneration,abnormal subchondral bone reconstruction and synovial inflammation,which seriously affects the quality of life.At present,the treatment methods that can effectively reverse the degeneration of condylar cartilage are relatively limited.Studies have shown that cell transplantation therapy based on mesenchymal stem cells(MSCs)can reverse the condylar cartilage degeneration of TMJ OA to some extent.Stem cells from human exfoliated deciduous teeth(SHED)are a class of MSCs that exist around the pulp blood vessels and can self-renew.Compared with other MSCs,SHED has the advantages of less ethical controversy,easy availability of sources,minimally invasive collection,and easy retention of high stem cell potential.A large number of studies have shown that SHED can induce bone and cartilage formation,has biological potential such as joint cartilage repair and inhibition of inflammatory response,and has better prospect for transformation and application.In this study,we intend to preliminarily explore the effect of SHED and its derivatives on the degeneration and prognosis of condylar cartilage in TMJ OA animal models,in order to provide new ideas for the clinical treatment of TMJ OA in the future.Objective:To preliminary investigate the effects of dental pulp stem cells from exfoliated deciduous teeth(SHED)and its derivatives on the outcome of temporomandibular joint osteoarthritis(TMJ OA).Methods:One hundred eight-week-old male Sprague-Dawley(SD)rats were randomly divided into the following groups:control group(CON group),sodium iodoacetate-induced TMJ OA group(MIA group),TMJ OA treated via SHED group(SHED group),TMJ OA treated via SHED conditioned media group(SHED-CM group),and TMJ OA treated via SHED extracellular vesicles group(SHED-EXO group).Animals were euthanized at two weeks and four weeks post-treatment.HE staining and Safranin O-Fast Green staining was performed to evaluate the degree of cartilage degeneration.Immunohistochemical staining was performed to detect the expression of Col Ⅱ in condylar cartilage.TUNEL fluorescent staining was introduced to detect apoptosis in cartilage cells.Western blotting and RT-qPCR were performed to detect the protein and mRNA expression of apoptosis-related molecules,cleaved-CASP3,BAX,and BCL2;pro-inflammatory factor IL1β,IL-6,TNFα,MMP3,ADAMTS5;and MAPK pathway-related molecules p-ERK,ERK,p-P38,and P38.Results:Compared with the CON groups,the MIA group exhibited a disordered arrangement of chondrocytes in each layer,regional loss of chondrocytes and a thicker fibrous layer.and the histological score of Mankin’s osteoarthritis was significantly increased.After treatment,the morphology of SHED,SHED-CM and SHED-EXO groups basically returned to normal,and there were no significant differences in fiber layer thickness and Mankin’s histological score between these groups and CON groups.Compared with the CON,SHED,SHED-CM,and SHED-EV groups,the percentages of safranin O-positive and Col Ⅱ-positive areas in condylar cartilage decreased significantly in the MIA group.The rate of TUNEL-positive cells in the MIA group was significantly higher than that in the CON group,and the rate of TUNEL-positive cells in the SHED,SHED-CM and SHED-EXO groups was significantly decreased by treatment.Western blotting showed that the protein expression levels of key molecules cleaved-CASP3,BAX,and BCL2 and MAPK pathway-related molecules p-ERK,ERK,p-P38,and P38 in the MIA group were significantly higher than those in the CON group,and the expression levels of each molecule in the SHED group,SHED-CM group and SHED-EXO group decreased after treatment.The qRT-PCR indicated that the expression of pro-inflammatory related factors IL1β,IL-6,TNFα,MMP3,and ADAMTS5 was significantly increased in the MIA group compared with the CON group,and the expression of pro-inflammatory related factors in the SHED group,SHED-CM group and SHED-EXO group was reduced by treatment.Conclusion:SHED and its derivatives can effectively reverse MIA-induced cartilage degeneration of rat condylars,suggesting that SHED and its derivative intra-articular injection of temporomandibular can be used as an effective method for the treatment of TMJ OA.