Wj. Trooster et al., THE EFFECT OF GONADECTOMY ON THE CLINICAL COURSE OF CHRONIC EXPERIMENTAL ALLERGIC ENCEPHALOMYELITIS, Clinical neurology and neurosurgery, 98(3), 1996, pp. 222-226
Experimental allergic encephalomyelitis (EAE) is an animal model for t
he human neurological disease multiple sclerosis (MS). Upon immunizati
on with guinea pig spinal cord under a low dose of Cyclosporin A, male
Lewis rats develop a severe chronic (relapsing) course of EAE (CR-EAE
). By contrast, female Lewis rats develop a more mitigated course of E
AE: only half of the female rats develop relapses. To Further analyze
factors determining this sexual dimorphism in the course of EAE, in th
e present study male and female Lewis rats were gonadectomized before
induction of CR-EAE. Now both male and female rats all developed a sev
ere chronic course of EAE, showing extensive pathological changes in t
he CNS. In the female sham-gonadectomy (control) group only one third
of the rats developed relapses. These female rats only showed mild pat
hological changes in the CNS. In the male sham-gonadectomy (control) g
roup all rats developed relapses of EAE and showed extensive pathologi
cal changes in the CNS. From these data we conclude that the presence
of the ovaries (partially) protects female rats against relapses of EA
E and CNS injury. Presence or absence of the testes apparently makes n
o difference on the course of EAE. We propose that sex hormones produc
ed in the ovaries protect female rats against relapses of EAE and unde
rlying CNS injury.