title: Strenuous Treadmill Running Induces a Chondrocyte Phenotype in Rat Achilles Tendons.
abstract: BACKGROUND Although tendinopathy is common, its underlying pathogenesis is poorly understood. This study aimed to investigate the possible pathogenesis of tendinopathy. MATERIAL AND METHODS In this study, a total of 24 rats were randomly and evenly divided into a control (CON) group and a strenuous treadmill running (STR) group. Animals in the STR group were subjected to a 12-week treadmill running protocol. Subsequently, all Achilles tendons were harvested to perform histological observation or biochemical analyses. RESULTS Histologically, hypercellularity and round cells, as well as disorganized collagen fibrils, were presented in rat Achilles tendon sections from the STR group. Furthermore, our results showed that the expression of aggrecan, collagen type II (Col II), and Sex-Determining Region Y Box 9 (Sox 9) were markedly increased in the STR group compared with that in the CON group. Additionally, the mRNA expression of bone morphogenetic protein-2 (BMP-2) and biglycan was significantly up-regulated in the STR group in contrast to that in CON group. CONCLUSIONS These results suggest that a 12-week strenuous treadmill running regimen can induce chondrocyte phenotype in rat Achilles tendons through chondrogenic differentiation of tendon stem cells (TSCs) by BMP-2 signaling.
authors.affiliation: Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China (mainland).
authors.forename: Shao-Yong
authors.initials: SY
authors.lastname: Xu
authors.affiliation: Laboratory Medicine Center, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China (mainland).
authors.forename: Shu-Fen
authors.initials: SF
authors.lastname: Li
authors.affiliation: Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China (mainland).
authors.forename: Guo-Xin
authors.initials: GX
authors.lastname: Ni
mesh_terms: D000125:Achilles Tendon / Q000502:physiology*; D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D019902:Chondrocytes / Q000166:cytology / Q000502:physiology*; D024043:Collagen Type II / Q000378:metabolism; D008297:Male; D010641:Phenotype; D010805:Physical Conditioning, Animal / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012420:Running / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology; D052256:Tendinopathy / Q000473:pathology*
chemical_list: D019485:Bone Morphogenetic Proteins; D024043:Collagen Type II
keywords: Biglycan; Bone Morphogenetic Protein 2; Tendinopathy