Thymosin alpha 1 is chemopreventive for lung adenoma formation in A/J mice

The effects of thymosin (THN) alpha1 were investigated using the urethane i njection carcinogenesis A/J mouse model. Lung adenomas were observed 2.5, 3 , and 4 months after urethane injection (400 mg/kg i.p.) into female A/J mi ce. Daily administration of THN alpha1 (0.4 mg/kg, s.c.) reduced lung adeno ma multiplicity significantly, by approximately 45, 40, and 17%, respective ly, 2.5, 3, and 4 months after urethane injection. Animals treated with THN alpha1 had a significantly greater white cell density than control A/J mic e. Endogenous THN alpha1-like peptides were detected in the mouse lung. By radioimmunoassay and by Western blot, prothymosin alpha, was detected in th e mouse lung. By immunocytochemistry, THN alpha1-like peptides were detecte d in all lung compartments including the bronchus, adenoma, bronchioles, an d alveoli. These results indicate that exogenous THN alpha1 prevents lung c arcinogenesis in A/J mice. (C) 2000 Published by Elsevier Science Ireland L td.