Expressão de Bcl-xL, Bax e caspase-3 em células 5 tronco mesenquimais de ratas após a diferenciação condrogênica in vitro na 6 presença de triiodotironina

Abstract

Chondrogenesis in vivo is controlled by several factors, including thyroid hormones. However, there is still no study verifying the effect of these hormones on apoptosis of bone marrow mesenchymal stem cells (BMMSC) and adipose tissue (ATSC) on chondrogenesis. Thus, the objective was to evaluate the expression of Bcl-xL, Bax and caspase-3 in MSC of rats after in vitro chondrogenic differentiation in the presence of triiodothyronine (T3). The cells underwent chondrogenic differentiation for 21 days without T3 (control group) and with different concentrations of T3 (0.01; 1; 100 and 1000 nM). After differentiation, immunohistochemistry was performed to label Bcl-xL, Bax and caspase-3. The reading was done using IHC profile digital image analysis software. Analysis of variance and Shapiro Wilk, Tukey and t-tests were performed. Bcl-xL protein in BMMSC, had its expression decreased in doses of 0.01; 1 and 100 nM, while in ATSC, there was an increase in the dose of 0.01 nM. Bax protein increased its expression in BMMSC at doses of 0.01 and 100 nM and, in ATSC, it also increased expression at a dose of 1000 nM. There was no difference in the expression of caspase-3 in BMMSC, however, in ATSC there was a decrease in doses of 1 and 1000 nM. Bcl-xL protein was predominantly similar between BMMSC and ATSC, however, Bax expression was higher in BMMSC in most of the studied doses, while caspase-3 expression was higher in BMMSC in all evaluated groups. It is concluded that T3 influences in a dose dependent manner on the protein expression of Bcl-xL and Bax, both in BMMSC and in ATSC and on the protein expression of caspase-3 in ATSC after chondrogenic differentiation, however, it does not influence this expression in BMMSC. The expression of Bax and caspase-3 is predominantly higher in BMMSC compared to ATSC.