In the present study, we compared the cell damage response in skeletal and
cardiac muscle tissue when exposed to doxorubicin. This was carried out by means
of a less invasive informative substitute to endomyocardiac biopsy based on
Hsp70 immunodetection and a subcellular analysis of the nucleolus. Male Sprague
Dawley rats (62 g body weight) were randomly distributed into 3 group, the
control and doxorubicin I and doxorubicin II groups, in which 15 and 25 mg/kg
body weight of doxorubicin (0.1 ml, i.v.) was administered, respectively. After
15, 30, 45 and 60 minutes, portions of the left and right ventricle wall and
interventricle wall, together with skeletal muscle from the posterior and
anterior member, were prepared for Hsp70 immunodetection by Western blot
analysis and ultrastructural study using the thin cut technique. Differential
cell response between the control and treated groups was observed in Hsp70
immunodetection and at the subcellular level. In the control group, the Hsp70
recognition levels and typical normal nucleolar morphology were similar, while
the treated groups showed variable-dependent Hsp70 recognition and segregation
of nucleolar components, forming ring-like figures of a variable-independent
nature. Comparison of cardiac and skeletal muscle tissue cell response to
doxorubicin toxic aggression revealed parallelism in terms of Hsp70 accumulation
in certain regions of both tissues (15 mg/kg body weight of doxorubicin), which
suggests that replacing endomyocardiac biopsy analysis with skeletal muscle
analysis may be a safe option.