Immunohistochemical Study on the SVCT Expression in the Spinal Cord of Experimental Allergic Encephalomyelitis (EAE) Model

Yoo, Young Bok

Abstract

Experimental allergic encephalomyelitis (EAE) lesions by autoimmune inflammatory mechanism are characterized by the activation of microglia and astrocytes during the peak symptomatic stage of the disease. Besides it is well known that ROS and nitric oxide (NO), which is come out from activated inflammatory cells, play important role in the pathogenesis of EAE lesions. And vitamin C (L-ascorbic acid), which may protect from the deleterious effect by reducing iron (Fe2+) or copper (Cu2+) ions and maintain tissue homeostasis by removing of oxygen free radical, is inevitable to help many enzymatic reactions of cells. Previous report already investigated expression and functional analysis on various vitamin C transporters of vitamin C in many cell types. However, the researches for the vitamin C transporters are mostly performed in the normal state but not disease model yet. Therefore, for the first time, we investigated to know whether the SVCT1, 2 immunoreactivity may be observed in the astrocyte of EAE rat spinal cord. In the comparison of control and peak time group, the number of SVCT1, 2 immunoreactive cell was inclined to increase (P<0.05) as respectively 100+/-29.93, 135+/-34.62 in the control group, and 179+/-54.29, 349+/-73.56 in the peak time group. SVCT2 immunoreactivity was not doubly colocalized with GFAP antibody in the control group. In contrast, the astrocytes of the peak time group showed SVCT2 immunoreactivity in the perivascualr region and the cell number of doubly (SVCT2, GFAP) colocalized was 15+/-5.67 (P<0.05). We are firstly demonstrated that, in the evolving processes of EAE, astrocytes are able to use the vitamin C via the SVCT2. Taken all findings into consideration, the present data on the typical anti-oxidant vitamin C and its transporters, which may play a role in removing ROS, could be considered as a target to the therapeutic strategy of EAE and is also very useful to identify the characterization of vitamin C in the biological organism.