Corneal lesions induced by the systemic administration of capsaicin in neonatal mice and rats.

Following a single subcutaneous injection of capsaicin to neonatal mice, a high incidence of corneal lesions with opacity developed after a long latency. The intensity of the lesions progressed for about 1 month in animals which had received a high dose (50 or 100 mg/kg) of capsaicin. Although the intensity gradually decreased thereafter, 50% of animals still exhibited a visible opacity 6 months after treatment. Similar corneal lesions were also produced in neonatal rats which had been injected with capsaicin. It is suggested that the corneal lesions induced by capsaicin may be due to destruction of the trigeminal nerve.