Protective effect of estrogen on experimental autoimmune encephalomyelitis / 国际药学研究杂志

ABSTRACT

Objective To explore the effect and mechanism of estrogen in mouse model with experimental autoimmune encephalomyelitis (EAE). Methods A mouse model with EAE was induced in female C57BL/6J mice by immunizing with MOG35-55 and CFA. The immunized mice were randomly divided into two groups. In treatment group, estrogen at 50 μmol/L was injected into mice by s.c. in a consecutive fashion from the day of myelin oligodendroglia glycoprotein (MOG) immunization until the day of experiment completion. Meanwhile, in control group, solvent was injected into mice by the same means. The disease score for EAE was recorded everyday. The secretion of TNF-α and IL-17A from cultured mouse splenic cell supernatant was tested by ELISA technique. The abundance of mRNA for TNF-α, IL-17A, PD-1 and PD-L1 in spinal cord was tested by real-time PCR method. The intracellular expression for TNF-α and IL-17A and the surface expression for CD4/PD-1, CD19/PD-L1, CD4/CD25/Foxp3, CD19/CD21/CD23 as well as CD19/ CD5/CD1dhigh of mouse splenocytes were tested by fluorescence activated cell sorting (FACS) method. Results The prophylactic treatment of estrogen could delay the progress in mouse EAE. Histopathological evaluation of mouse spinal cord specimen showed reduced demyelination and inflammatory cell invasion by estrogen treatment. Furthermore, both TNF-α and IL-17A production in estrogen treated mice was significantly downregulated compared to those in control group mice. However, the transcription and expression level for PD-1 in CD4+T cells and that for PD-L1 in CD19+B cells were observed to be upregulated in estrogen treated mice. Also, the percentages of CD19+CD21highCD23low and CD19+CD5+CD1dhigh Breg cells in splenocytes were augmented by estrogen treatment. In contrast, no changes were observed for the proportion of the splenic CD4+CD25+Foxp3+Tregs in mice composed to estrogen treatment with comparison to those in mice with vehicle treatment. Conclusion The prophylactic treatment of estrogen can delay the disease progress in EAE mice, likely through the upregulation of PD-1/PD-L1 pathway and Breg cells.