PENTOXIFYLLINE DELAYS THE ONSET OF EXPERIMENTAL ALLERGIC ENCEPHALOMYELITIS IN MICE BY MODULATING CYTOKINE PRODUCTION IN PERIPHERAL-BLOOD MONONUCLEAR-CELLS

The effect of pentoxifylline (PTX) on experimental allergic encephalom yelitis (EAE) in mice, a known animal model of multiple sclerosis (MS) , was investigated, PTX was orally administrated at 10, 40 and 100 mg/ kg/day, respectively. Although oral PTX at these doses had no signific ant effect on the incidence and severity of EAE, oral PTX (40 mg/kg/da y) alone produced a significant delay in the onset of EAE. Semiquantit ative reverse transcriptase-polymerase chain reaction analysis reveale d that PTX at this dose reduced the mRNA levels for tumor necrosis fac tor (TNF)-alpha, interleukin (IL)-1 beta and IL-6 in peripheral blood mononuclear cells (PBMC) of mice with EAE. A histopathological study s howed that PTX treatment delayed infiltration of inflammatory cells in the central nervous system (CNS) of mice with EAE, These results indi cated that the tolerable dose of PTX had a suppressive effect on the i nduction phase of EAE by modulating cytokine production in PBMC but ha d no effect on the severity of EAE. The findings in the present study with animals suggested that a tolerable dose of PTX might prolong the intervals between relapses in MS, but might not improve the clinical s ign and symptoms of MS.