Guinea pigs and athymic nude (RNU/RNU) rats were used to assess the efficacy of three orally administered
antifungal agents--
Tolciclate,
Tolnaftate, and
Ketoconazole--against Trichophyton mentagrophytes
dermatophytosis. All three
antifungal agents inhibited the test strain of T. mentagrophytes in vitro.
Antifungal agents were tested in intervention (oral
therapy started 5 days after challenge) or prophylaxis (oral
therapy started 5 days before challenge) protocols. Oral treatment of
dermatophytosis on guinea pig skin demonstrated that
Tolciclate and
Tolnaftate alleviated clinical symptoms and shortened the duration of the
dermatophytosis, in comparison to nontreated controls. Assessment of antifungal efficacy in the guinea pig model was time consuming (30-35 days) and variability in the duration and severity of clinical symptoms on guinea pig skin was common. Oral
therapy of chronically infected athymic rats demonstrated that
Tolciclate,
Tolnaftate, and
ketoconazole were effective
antifungal agents in vivo. Obvious improvement in clinical symptoms of
dermatophytosis (i.e. less
erythema and fewer lesions) was evident with all three
antifungal agents within 10 days of starting oral
therapy. By day 20, athymic rats that were treated with either
Tolciclate or
Ketoconazole showed marked clinical improvement of the chronic
dermatophytosis. Chronically infected athymic rats, which lack thymus matured T-cells, are a promising new model to evaluate the efficacy of
antifungal agents by culture, histology, and visual observations of clinical symptoms.