PROTECTION AGAINST CYTOSINE ARABINOSIDE-INDUCED ALOPECIA BY MINOXIDIL IN A RAT ANIMAL-MODEL

Background. Alopecia is one of the most physically and psychologically distressing side effect of cancer chemotherapeutic agents. In the past 2 years, we reported that: (a) treatment of 8-day-old rats with 1-B-D-arabinofuranosylcytosine (Ara-C), doxorubicin, and cyclophosphamide (CYC) consistently produced alopecia; (b) Imuvert, a biological response modifier, produced complete protection against alopecia induced by Ara-C and doxorubicin, but not that produced by eve, most probably through the release of interleukin-1; and (c) n-acetylcysteine protected against CYC-induced alopecia in the newborn rat. Methods. As an extension to these observations, we chose to test the efficacy of minoxidil, a drug known to be a hypertrichotic agent, in preventing chemotherapy-induced alopecia in the newborn rat animal model. Results. Minoxidil, when injected locally, offered good local prevention against Ara-C but not eve-induced alopecia. Minoxidil 2% dissolved in a vehicle of ethanol, propylene glycol, and water was not effective when applied topically. Conclusions. The mechanism of action of minoxidil in its prevention against Ara-C-induced alopecia is currently unknown. This observation may shed some light on the in vivo mechanism of action of minoxidil and may prove to be important in our efforts to search for agents to prevent alopecia among patients receiving chemotherapy.