GENE EXPRESSION OF HSP70 IN HUMAN OSTEOBLASTIC CELLS CULTURED ON TITANIUM.

BM08

Albuquerque, GC (1) - gustalbuquerque@usp.br

Crippa, GE (1);

Pizauro, JM (2);

Oliveira, PT(1);

Beloti, MM(1);

Rosa, AL(1).

Laboratório de Cultura de Células – FORP/USP (1)FAMV/UNESP - Jaboticabal (2)

The heat shock protein of 70 kD (HSP70) plays a role in the maintenance of cellular homeostasis and prevention of apoptosis induced by stress. HSP70 presents three isoforms, one constitutive and two induced, mainly for temperature increase. The aim of this study was to evaluate the effect of culturing human osteoblastic cells in presence of titanium (Ti) on expression of HSP70. Cells enzymatically released from bone alveolar fragments were cultured in osteogenic medium on Ti discs and tissue culture polystyrene (TCP) for 10 days. After that, total RNA was obtained for gene expression evaluation of constitutive HSP70 (HSP1L) and induced ones (HSPA1A and HSPA1B) by real-time PCR. Cells grown on TCP were exposed to 37, 43 or 47° C for 120 min as a positive control. The results of experiments carried out in triplicate were compared by Kruskal - Wallis test or Mann-Whitney test. The increase in temperature has not changed the gene expression of constitutive hsp70, but increased the expression of both induced HSP70. For cells grown on Ti, gene expression of constitutive and induced HSP70 were reduced in comparison to TCP. The results suggest that Ti does not induce stress in human osteoblastic cells.