Damage of urinary/respiratory system and survival rate is affected by gender in EAE model of Lewis rat

ABSTRACT

Background: Multiple sclerosis (MS) is a demyelinating chronic inflammatory disease of the central nervous system.Experimental autoimmune encephalomyelitis (EAE) is a widely used model for MS based on autoimmune and histopathological similarities. Women are more susceptible to multiple sclerosis than men. This susceptibility has been attributedto sex hormones, sex-linked gene, and more robust immune responses in females. The aim of this study was to comparesurvival rate and severity of disease in terms of clinic-pathological signs including nasal bleeding, urinary incontinenceand bleeding from urinary tract rate between males and females affected by EAE.Materials, Methods & Results: Lewis rats aged 7-8 weeks were immunized subcutaneously with a homogenate ofguinea pig spinal cord and complete Freunds adjuvant (CFA). Each rat received 50 μg guinea pig spinal cord and 400 μgMycobacterium tuberculosis. Animals were daily weighed and clinical signs of disease were evaluated until day 36 postimmunization. Incidence, survival rate, clinic-pathological signs including nasal bleeding, urinary tract bleeding, and urinaryincontinence were evaluated. To assess the degree of inflammation at the peak of the disease, kidney and lung were dissected,fixed, and examined. The susceptibility to EAE in male and female rats was 100%. The day that the first clinical signs wereobserved was 7 days for both males and females after the immunization. Weight curve of EAE-affected male and femaleanimals were significantly different from their corresponding healthy animals (P < 0.001). The course of clinical scoreshowed a significant difference between males and females (P < 0.04). There was no significance association between sexand incidence. Survival analysis indicated a significant high mortality in male group (P = 0.001). The coagulopathy signin females, including nasal bleeding and urinary incontinence, decreases as disease progresses...(AU)