Apoptotic changes in a full-lengthened immobilization model of rat soleus muscle.

Abstract

Lengthened immobilization may prevent muscle shortening, and help maintain normal muscle length. However, its apoptotic effects remain unclear. We evaluated the effects of long-term immobilization on apoptotic proteins. Rat soleus muscles were immobilized by casting in a neutral (NEUT) or lengthened (LENG) position for 21 days. We evaluated dynamic weight load and muscle atrophy following the 21-day period using hematoxylin and eosin staining. We measured Bax (pro-apoptotic Bcl-2 family member), MyoD (myogenic differentiation factor D), MYH (myosin heavy chain), and cleaved poly(ADP-ribose)polymerase levels and examined apoptotic nucleus expression. Decreased dynamic weight load and muscle atrophy changes were observed in LENG. Both NEUT and LENG showed significantly reduced levels of MYH. LENG showed a significant increase in Bax and MyoD expression as well as in the number of apoptotic nuclei. Long-term lengthened immobilization may increase apoptotic changes and decrease muscle formation proteins in muscle. Muscle Nerve 59:263-269, 2019.