Comparison of expression of apoptosis regulatory proteins in the adipose tissue of tumor-bearing and diet-restricted rabbits

We investigated the expression of apoptosis regulatory proteins in the adip ose tissue of tumor-bearing and diet-restricted rabbits, and analyzed the d ifferences between the two groups. The apoptotic index in the tumor-bearing group was 25.1 12.4 on day 10 and increased to 27.2+/-14.4 by day 20. Ther eafter, however, it gradually decreased, falling to 11.2+/-7.8 on day 30 an d 0.67+/-0.88 on day 40. By contrast, no apoptotic cells were detected in t he diet-restricted group at any of the times examined. Bcl-2 immunoreactivi ty was either not detected at all, or was only weakly observed in both grou ps. Bax expression, on the other hand, gradually increased after implantati on in the tumor-bearing group. In 2 of the 5 tumor-bearing rabbits, Bax exp ression in adipocytes was moderate 10 days after tumor implantation, and st rong by day 20, but steadily decreased thereafter. By contrast, hardly any Bax-immunopositive cells were detected in the diet-restricted group. These results suggested that loss of body weight in the tumor-bearing,group was d ifferent from that in the diet-restricted group, and that it was related to adipocyte apoptosis.