Identification of key miRNAs in unilateral mastication‐induced disruption of cartilage homeostasis

Abstract

ObjectiveThe present study identified potentially pivotal miRNAs contributing to chondrogenic differentiation in temporomandibular joint suffering abnormal stress.Materials and MethodsSprague–Dawley rats were randomly divided into control and experimental unilateral mastication (EUM) group. Bone micro‐structure parameters was detected by micro‐CT, and FGF‐1 and MMP‐1 expression was examined by immunohistochemistry. Differentially expressed miRNAs of bilateral condyle cartilage were screened via miRNA microarray at 4‐ and 8‐week EUM, then further verified using quantitative reverse‐transcription PCR. Over‐expression of five differentially expressed miRNAs in chondrocytes was triggered by transfecting miRNA mimics. The expression of MMP‐13, Col‐II, OPN, and Runx2 was verified by western blotting.ResultsExpressions of FGF‐1 and MMP‐1 in right condyles gradually increased from 2 to 6 weeks after EUM. A total of 20 differentially expressed miRNAs were regulated by EUM, which related to cell proliferation, invasion, and osteoblast differentiation pathways. The over‐expression of miR‐148a‐3p and miR‐1‐3p led to down‐regulation of Col‐II, while MMP‐13 and Runx2 were up‐regulated by induction of hypotrophic differentiation or IL‐1β stimulation. These findings suggested that miR‐148a‐3p and miR‐1‐3p promote chondrogenic differentiation.ConclusionsSeveral pivotal miRNAs were found to be related to chondrogenic differentiation, which provides novel insight into pathogenic mechanisms of cartilage homeostasis.

A critical size volumetric muscle loss model in mouse masseter with impaired mastication on nutrition

“…Unilateral mastication pattern is a manifestation of impaired mastication function, 42 which can be caused by pain and impairments 43–45 . There is increasing evidence that prolonged unilateral mastication adversely affects maxillofacial soft and hard tissues due to the presence of asymmetric forces 46–49 . In this study, however, we did not observe any significant damage to the articular cartilage, trabecular bone of the condyle or tooth following unilateral masseter VML in a period of 28 days.…”

“…[43][44][45] There is increasing evidence that prolonged unilateral mastication adversely affects maxillofacial soft and hard tissues due to the presence of asymmetric forces. [46][47][48][49] In this study, however, we did not observe any significant damage to the articular cartilage, trabecular bone of the condyle or tooth following unilateral masseter VML in a period of 28 days. The mastication behaviour changes may be fully compensated by the dentoskeletal system.…”