BACKGROUNDOur previous study had demonstrated that ulinastatin (UTI) had a neuroprotective effect in experimental autoimmune encephalomyelitis (EAE). Methylprednisolone has been recommended to be a standard drug in multiple sclerosis (MS) therapies. The present study was to investigate the protective effects of UTI combined methylprednisolone in EAE.

METHODSMice were divided into a UTI treatment group, a methylprednisolone treatment group, a combined treatment group with UTI and methylprednisolone, a normal saline treatment group, and a normal control group. EAE mice were induced in groups receiving different combined treatments, or respective monotherapies. Demyelination was evaluated by Solochrome cyanin staining. 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP)/ myelin basic protein (MBP)/ the precursor form of nerve growth factor (proNGF)/p75/ inducible nitric oxide synthase (iNOS) proteins in cerebral cortex of EAE were detected by Western blotting.

RESULTSThe combined treatment group had a lower clinical score (0.61 ± 0.06) and demyelinating score (1.33 ± 0.33) than the groups with normal saline (clinical score: 1.39 ± 0.08, P < 0.001; demyelinating score: 2.75 ± 0.49, P < 0.05) or monotheraphies. Compared with the saline treated EAE group, UTI combined methylprednisolone significantly increased expressions of CNP (1.14 ± 0.06 vs. 0.65 ± 0.04, P < 0.001), MBP (1.28 ± 0.14 vs. 0.44 ± 0.17, P < 0.001), and decreased expressions of proNGF (1.08 ± 0.10 vs. 2.32 ± 0.12, P < 0.001), p75 (1.13 ± 0.13 vs. 2.33 ± 0.17, P < 0.001), and iNOS (1.05 ± 0.31 vs. 2.17 ± 0.13, P < 0.001) proteins in EAE. Furthermore, UTI combined methylprednisolone could significantly upregulate MBP (1.28 ± 0.14 vs. 1.01 ± 0.15, P < 0.05) expression and downregulate iNOS (1.05 ± 0.31 vs. 1.35 ± 0.14, P < 0.05) expression compared to methylprednisolone treatment EAE group. And proNGF expression was significantly lower in combined treatment (1.08 ± 0.10) than that in UTI (1.51 ± 0.24, P < 0.05) or methylprednisolone (1.31 ± 0.04, P < 0.05) treatment group.

CONCLUSIONCombination treatment of UTI with methylprednisolone was shown to protect EAE, suggesting that combination therapy is a potential novel treatment in MS.