Triiodotironina não aumenta a diferenciação osteogênica reduzida pela idade de células-tronco mesenquimais da medula óssea de ratas

Abstract

OBJETIVO: Avaliar se a adição de T3 aumenta o potencial osteogênico das células-tronco mesenquimais da medula óssea (CTM-MO) de ratas adultas normais comparado ao de ratas jovens. MATERIAIS E MÉTODOS: CTM-MO foram cultivadas em meio osteogênico e separadas em seis grupos: 1) CTM-MO de ratas jovens; 2) CTM-MO de ratas adultas; 3, 4, 5 e 6) CTM-MO de ratas adultas com T3 nas concentrações de 0,01; 1; 100 e 1000 nM, respectivamente. Foram avaliados: atividade da fosfatase alcalina, conversão do dimetiltiazol (MTT) e síntese de colágeno aos sete, 14 e 21 dias e celularidade e número de nódulos de mineralização aos 21 dias de diferenciação. RESULTADOS: T3 reduziu significativamente a conversão do MTT, a atividade da fosfatase alcalina, a síntese de colágeno e a formação dos nódulos de mineralização em pelo menos uma das doses e dos períodos estudados (p < 0,05). Os valores foram menores quando comparados aos das CTM-MO de ratas jovens e adultas sem T3 (p < 0,05). CONCLUSÃO: T3 apresenta efeitos negativos sobre os fatores envolvidos na diferenciação osteogênica das CTM-MO de ratas adultas.

Dose-dependent effect of triiodothyronine on the chondrogenic differentiation of mesenchymal stem cells from the bone marrow of female rats

“…After seven, 14 and 21 days, the expression of Sox9, collagen II (Col II) and aggrecan was evaluated by qPCR, and chondrogenic matrix formation was performed. The doses of T3 were established according to studies conducted by Boeloni et al ., and the dose of 0.01 n m was similar to the physiological dose. Thus, five experimental groups were constituted: (1) BMMSCs without T3; (2) BMMSCs with T3 (0.01 n m ); (3) BMMSCs with T3 (1 n m ); (4) BMMSCs with T3 (100 n m ); and BMMSCs with T3 (1000 n m ).…”

“…After four runs and until a cell confluence of 80-90% was obtained, the phenotypic characterization of the BMMSCs was performed by flow cytometry according to an established protocol. [33,39] The reading and analysis were performed on a Fluorescence Activated Cell Analyzer (FACScan) using Cell Quest software, with an acquisition of 20 000 events, with forward scatter (FSC) and side scatter (SSC) parameters on a linear scale and FL1 (relative fluorescence) on a logarithmic scale that detects light of 530 nm wavelength, which corresponds to green fluorescence, for analysis by the WinMDI program by dot plot charts and histograms. The primary antibodies used were as follows: anti-CD45 (clone 69 mouse), anti-CD54 (clone 1A29 mouse), anti-CD73 (clone 5 F/B9 mouse) and anti-CD90 (clone Ox-7 mouse) (BD Biosciences, San Jose, CA, USA).…”

“…Previous studies have shown that thyroid hormones may positively influence the in‐vitro osteogenic differentiation of BMMSCs from young female rats in a dose‐dependent manner . However, in‐vitro treatment with T3 has negative effects on factors involved in the osteogenic differentiation of BMMSCs from adult female rats . It is not known whether in‐vitro treatment with T3 could also increase the chondrogenic potential of female rat BMMSCs.…”

“…[32] However, in-vitro treatment with T3 has negative effects on factors involved in the osteogenic differentiation of BMMSCs from adult female rats. [33] It is not known whether in-vitro treatment with T3 could also increase the chondrogenic potential of female rat BMMSCs. BMMSCs have nuclear receptors for thyroid hormones.…”