Mechanisms and Therapeutic Effects of Human Olfactory Mucosa-Derived Mesenchymal Stem Cells on Experimental Autoimmune Encephalomyelitis in Mice / 中山大学学报(医学科学版)

ABSTRACT

@#【Objective】 To study the mechanisms and therapeutic effects of human olfactory mucosa-derived mesenchymal stem cells（OMSC）on experimental autoimmune encephalomyelitis（EAE）in mice.【Methods】Under local anesthesia by using nasal endoscopy，olfactory epithelia of healthy donors were obtained，digested and cultured up to the 5th passage. OMSC were identified，differentiated and stained. EAE models were induced in C57 female mice by myelin oligodendrocyte glycoprotein（MOG35- 55）and pertussis toxin（PT）. Neurological function was documented daily. On day 16 after immunization（peak of incidence），the mice were divided randomly into two groups and treated with OMSC and PBS via tail vein injection respectively. On day 24 after immunization ，blood was collected from angular vein and levels of IL-10，IL-17，IFN-γ and IL-6 were determined by cytometric beads array（CBA）. The size of the spinal cord lesion in mice was observed and measured by using HE and LFB staining. Peripheral blood lymphocytes（PBL）of healthy donors were obtained and then co-cultured with OMSC. The proportions of CD4+ T cells secreting IFN- γ（Th1 cells）in lymphocyte group and co-culture group were compared after 2 days of cultivation. Adding IDO or COX pathway inhibitor to co- culture group and cultivating for 2 days，we observed and compared the proportions of Th1 cells in lymphocyte group，co-culture group and inhibitor treatment group respectively.【Results】OMSC exhibited certain mesenchymal stem cell-like characteristics with respect to expression of stem cell surface markers and multilineage differentiation potentials. After induced by MOG35- 55 and PT，EAE models showed different levels of neurological damage. Compared with those in PBS treatment group，in OMSC treatment group，the severity of neural dysfunction in mice was significantly reduced（P =0.002），the level of IFN-γ in serum was lower（P = 0.032），but no significant differences in the levels of IL-10，IL-17 and IL-6 were found between two groups. HE and LFB staining revealed that the inflammatory infiltration and demyelinating areas in OMSC treatment group were less than those in PBS treatment group. The proportion of Th1 cells was lower in co-culture group than that in lymphocyte group（P = 0.001），higher in IDO inhibitor group than that in co-culture group（P = 0.01），but no significant difference was found between IDO inhibitor group and lymphocyte group or between COX inhibitor group and co-culture group.【Conclusions】OMSC may regulate the proportion of Th1 lymphocytes through IDO pathway so as to inhibit the demyelinating injuries of EAE in mice. This study provides a new idea for the clinical treatment of multiple sclerosis.