ABSTRACT
A small amount of the myotube-like structures (chained nuclei) are present in skeletal muscle independently of disease. These experiments show that the incidence of the myotube-like structure increases with the advance of age in mice. Moreover, it is shown that the DNA in the myotube-like structure is not fragmented. That is, the myotube-like structures were TUNEL (Terminal deoxynuc-leotidyl transferase (TdT) -mediated dUTP-biotin Nick-End labeling) negative. Moreover, we detected the polyadenylated mRNA around the myotube-like structure by using an in situ hybridization technique. This suggests that the myotube-like structure has transcription activity.<BR>This report indicates that the myotube-like structure is a useful indicator of aging in skeletal muscle.