Is pig spinal cord hydrolysate safe for treatment Experimental Allergic Encephalomyelitis in rats?

EAE (Experimental Allergic Encephalomyelitis) is the animal model of Multiple Sclerosis, an autoimmune and neurodegenerative human disease. Proposed method for autoimmune diseases treatment is to evoke oral tolerance, which is lack of response to fed antigen. Our previous experiments showed that pig spinal cord hydrolysate, which is source of myelin antigens is able to evoke oral tolerance in EAE rats. The aim of our study was to investigate, if treatement with pig spinal cord hydrolysate has any toxic effects on rats. Twelve female Lewis rats were fed with pig spinal cord hydrolysate (500mg/kg) or PBS (control group, 0,5ml per rat) each day for one month. One day after the last day of feeding animals were sacrified, and the main organs were collected. Organs were fixed in 10% formalin, postfixed in paraffin, cut into slices and stained with hematoxylin and eosin. Slices were analysed using the light microscope. Every spleen, thymus and adrenal gland was weighted to count relative mass. Number of spleen megakaryocytes in 1mm2 was counted. There were no changes observed in any brain, heart, stomach, intestine, uterus and ovary preparations. We observed single changes in rats liver, kidney, thymus, mesenteric lymph node, adrenal gland, and in the number of spleen megakaryocytes, but not corelated with experimental group. The fact that we did not find any significant changes in rat organs can confirm that pig spinal cord hydrolysate is safe for rats. Supported by N302 009 32/1139 grant.