Muscle atrophy and histopathology of the soleus in 6-mercaptopurine-treated rats.
This study was conducted to examine the histochemical changes occurring due to neonatal 6-mercaptopurine (6-MP) treatment (2 mg/kg, sc, between 2 and 22 days after birth) in the slow-twitch muscle (soleus) of adult male and female rats. At 6 months of age, the control and the 6-MP-treated rats were evaluated for the sciatic nerve conduction to the soleus and for the soleus atrophy and histopathology of the type I (slow-twitch) and type II (fast-twitch) muscle fibers. Compared to the normal controls, the 6-MP-treated male and female rats showed similar sciatic nerve conduction to the soleus. However, there was a significant muscle atrophy (57-60%, P less than 0.01) and a decrease in fiber areas of the type I (42-54%, P less than 0.05) and type II (41-71%, P less than 0.01) fibers. The number of type II fibers declined significantly (7.4-14.8%, P less than 0.05). It is proposed that the soleus muscle atrophy and histopathology in 6-MP-treated rats is unrelated to nerve conduction defects and may be related to growth inhibition caused by an interference of the drug during normal differentiation of muscle fibers.
Jaweed
M M
MM
Alleva
F R
FR
Herbison
G J
GJ
Ditunno
J F
JF
Balazs
T
T
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D005260:Female; D008297:Male; D015122:Mercaptopurine / Q000494:pharmacology* / Q000633:toxicity; D009132:Muscles / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D009133:Muscular Atrophy / Q000139:chemically induced*; D009431:Neural Conduction / Q000187:drug effects; D051381:Rats; D012584:Sciatic Nerve / Q000187:drug effects
D015122:Mercaptopurine; D000251:Adenosine Triphosphatases