title: Decreased proliferation of aging tenocytes is associated with down-regulation of cellular senescence-inhibited gene and up-regulation of p27.
abstract: Symptomatic tendinopathy tends to be age-related. However, the molecular mechanisms of ageing and its effects on tenocyte proliferation and cell cycle progression are unknown. We examined tenocytes from Achilles tendons in rats from three age groups (young, 2 months; middle-aged, 12 months, and near senescence, 24 months). Tenocyte proliferation was assessed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry. Senescence-associated β-galactosidase (SA β-gal) staining was performed in all groups of tenocytes. mRNA and protein expression of cellular senescence-inhibited gene (CSIG) and p27 was measured by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, respectively. The results of MTT assay revealed that tenocyte proliferation decreased with age (p < 0.05). Cell cycle progression was arrested at G0/G1 phase in senescent tenocytes. More senescent tenocytes expressed SA β-gal than young tenocytes did. By RT-PCR and Western blot analysis, the gene and protein expression of CSIG was found to be down-regulated, whereas that of p27 was up-regulated with age. In conclusion, the proliferation of tenocytes declines with age and is associated with the down-regulation of CSIG and up-regulation of p27.
authors: Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital at Linkou, Taiwan.
authors: Wen-Chung
authors: WC
authors: Tsai
authors: Hsiang-Ning
authors: HN
authors: Chang
authors: Tung-Yang
authors: TY
authors: Yu
authors: Cheng-Hsiu
authors: CH
authors: Chien
authors: Li-Fen
authors: LF
authors: Fu
authors: Fang-Chen
authors: FC
authors: Liang
authors: Jong-Hwei S
authors: JH
authors: Pang
mesh_terms: D000125:Achilles Tendon / Q000166:cytology* / Q000378:metabolism; D000375:Aging / Q000378:metabolism*; D000818:Animals; D049109:Cell Proliferation; D002478:Cells, Cultured; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism*; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D050760:Cyclin-Dependent Kinase Inhibitor p27; D001616:beta-Galactosidase