Expression of apoptosis regulatory proteins in the skeletal muscle of tumor-bearing rabbits compared with diet-restricted rabbits.
The mechanism of body weight loss in the tumor-bearing state is still unclear. In this study, we investigated expressions of apoptosis regulatory proteins in the skeletal muscle of tumor-bearing and diet-restricted rabbits, and tried to evaluate the differences between the two groups. The apoptotic index (AI) in the tumor-bearing group was 28.1+/-2.84 on day 10. By day 20, many more apoptotic cells were found (AI: 40.5+/-3.20), but then after day 20 their numbers gradually decreased (AI: 9.67+/-2.22 on day 30 and 0.93+/-0.96 on day 40). By contrast, no apoptotic cells were detected in the diet-restricted group at any of the times examined. Bcl-2 immunoreactivity was either not detected at all or only weakly observed in both groups. By contrast, Bax expression increased gradually after implantation in the tumor-bearing group. Bax expression in skeletal muscle cell was graded (moderate) 10 days after tumor implantation, and (high) by day 20, in 2 of the 5 tumor-bearing rabbits. After day 20, however, Bax immunoreactivity decreased continuously in the tumor-bearing group. By contrast, hardly any Bax-immuno-positive cells were detected in the diet-restricted group. These results suggest that loss of body weight in the tumor-bearing group is different from that in the diet-restricted group, and is related to apoptosis of skeletal muscles.
Ishiko
O
O
Department of Obstetrics and Gynecology, Osaka City University Medical School, 1-4-3 Asahi-machi, Abenoku, Osaka 545-8585, Japan. ishikoo@msic.med.osaka-cu.ac.jp
Sumi
T
T
Yoshida
H
H
Hyun
Y
Y
Ogita
S
S
D000273:Adipose Tissue; D000818:Animals; D017209:Apoptosis / Q000235:genetics; D015992:Body Mass Index; D001835:Body Weight; D053938:DNA Fragmentation / Q000235:genetics; D004038:Diet, Reducing; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry* / Q000378:metabolism / Q000473:pathology; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis*; D011817:Rabbits; D013997:Time Factors; D051028:bcl-2-Associated X Protein
D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein