TREATMENT OF ACUTE EXPERIMENTAL ALLERGIC ENCEPHALOMYELITIS IN THE LEWIS RAT WITH THE SEX-HORMONE PROGESTERONE

In the present study we examined the effect of treatment with progesterone on experimental allergic encephalomyelitis (EAE), an animal model for the human neurological disease multiple sclerosis (MS). Acute EAE was induced in female Lewis rats by immunization with guinea pig spinal cord. From 4 days before induction until 21 days after induction the rats-were treated with progesterone suspended in vehicle or with vehicle alone. All rats developed histological signs and clinical symptoms, characteristic for EAE. Treatment with progesterone: resulted in partial protection against the histological signs, but did not suppress the clinical symptoms. The hormone treatment had no effect on the thymus or spleen. Therefore we suggest that treatment with progesterone protected against the histological signs of EAE through a peripheral immune mechanism.