Effect of fluoxetine treatment on neurotoxicity induced by lysolecithin in male rats

Abstract

Demyelination disorder is an unusual pathologic event, which occurs in the central nervous system (CNS). Multiple sclerosis (MS) is an inflammatory demyelinating disease that affects the CNS, and it is the leading cause of disability in young adults. Lysolecithin (LPC) is one of the best toxin-induced demyelination models. In this study, a suitable model is created, and the effect of fluoxetine treatment is examined on this model. In this case, it was assumed that daily fluoxetine treatment had increased the endogenous remyelination in the LPC model. This study was focused on investigating the influence of the fluoxetine dose of 5 or 10 mg/kg per day for 1 and 4 weeks on LPC-induced neurotoxicity in the corpus callosum region. It was performed as a demyelinating model in male Wistar rats. After 3 days, fluoxetine was injected intraperitoneally (5 or 10 mg/kg per day) for 1 and 4 weeks in each group. After completing the treatment course, the corpus callosum was removed to examine the gene expression and histological analysis was performed. The results of the histopathological study of hematoxylin and eosin staining of the corpus callosum showed that in 1 and 4-week treatment groups, fluoxetine has reduced the level of inflammation at the LPC injection site (5 and 10 mg/kg per day). Fluoxetine treatment in the luxol fast blue (LFB) staining of the corpus callosum has been led to an increase in myelination capacity in all doses and times. The results of the genetic study showed that the fluoxetine has significantly reduced the expression level of tumor necrosis factor-α, nuclear factor κβ, and induced nitric oxide synthase in comparison with the untreated LPC group. Also, the fluoxetine treatment has enhanced the expression level of the forkhead box P3 (FOXP3) gene in comparison with the untreated group. Fluoxetine has increased the expression level of myelination and neurotrophic genes such as myelin basic protein (MBP), oligodendrocyte transcription factor 2 (OLIG2), and brain-derived neurotrophic factor (BDNF). The outcomes demonstrated that fluoxetine reduces inflammation and strengthens the endogenous myelination in the LPC-induced demyelination model; however, supplementary studies are required for specifying the details of its mechanisms.