Ferulic Acid Ameliorates Cell Injuries, Cognitive and Motor Impairments in Cuprizone-Induced Demyelination Model of Multiple Sclerosis

Abstract

Objective: Ferulic acid (FA) is a phenolic compound that exhibits neuroprotective effects in the central nervous system (CNS). This study was conducted to evaluate the potential effects of FA on the cognitive and motor impairments in the cuprizone-induced demyelination model of multiple sclerosis (MS).

Materials and methods: In this experimental study, demyelination was induced in mice by feeding them with chow containing cuprizone (CPZ) 0.2% for 6 weeks. Mice in the control group received normal chow. Mice in the CPZ+Veh, CPZ+FA10, and CPZ+FA100 groups received saline, and FA at a dose of 0, 10, or 100 mg/kg (intraperitoneal, I.P., daily) respectively. After cognitive and motor assessments, under anaesthesia, animal brains were removed for evaluating the histological, apoptosis, and molecular changes.

Results: The results showed that FA increased freezing behaviour in contextual (P<0.05) and cued freezing tests (P<0.05). FA also reduced the random arm entrance (P<0.01) and increased spontaneous alternations into the arms of Y-maze compared to the CPZ+Veh group (P<0.05). Time on the rotarod was improved in rats that received both doses of FA (P<0.01). Demyelination, apoptosis, and relative mRNA expression of p53 were lower in the FA-treated groups relative to the CPZ+Veh group (P<0.01). In addition, FA increased mRNA expression of brain-derived neurotrophic factor (Bdnf), Olig2, and Mbp (P<0.05) but decreased GFAP mRNA expression compared to the CPZ+Veh group (P<0.01).

Conclusion: The results of this study showed that FA plays a significant neuroprotective role in CPZ models of demyelination by reducing neuronal apoptosis and improving oligodendrocytes (OLs) growth and differentiation.

Keywords: Apoptosis; Cuprizone; Demyelination; Ferulic acid; Oligodendrocyte.

Fig 1

Effect of FA on cuprizone-induced impairments in cognitive function (freezing and cued behaviors in fear conditioning test, and the number of arm entries and spontaneous alternations in Y-maze) and motor coordination (time on road and the number of falling/flipping in rotarod). *; Significant difference when compared to control group, #; Significant difference when compared to CPZ+Veh group, *; P<0.05, **; P<0.01, ***; P<0.001, #; P<0.05, ##; P<0.01, FA; Ferulic acid, CPZ; Cuprizone, and Veh; Vehicle. Data are mean ± SEM.

Fig 2

Light micrographs showing histological sections of brains from rats in CC area. Arrows and open triangles show OLs and demyelination loci respectively. A, B. Control group, C, D. CPZ+Veh group, E, F. CPZ+FA 10, G, H. CPZ+FA 100 (the right column, 40x and the left column 400×). I. The histogram represents demyelination scores of CC in different groups. Demyelination score data are expressed as the mean ± SEM and analysed using one-way ANOVA followed by post hoc Turkey’s test. ***; P<0.001: significant difference when compared to the control group, #; P<0.05: significant difference when compared to CPZ+Veh group, OLs; Oligodendrocytes, FA; Ferulic acid, CPZ; Cuprizone, and Veh; Vehicle.

Fig 3

The apoptotic rate in different experimental groups light micrograph pictures (400×) of CC in experimental groups. A. Control group, B. CPZ+Veh treated group, C. CPZ+FA10 treated group, D. CPZ+FA100 treated group. The arrow indicates apoptotic cells. E. Quantitative analysis for calculating the ratio of TUNEL-positive cells to total cell number. F. The mRNA levels of P53 relative to HPRT in the corpus callosum as determined by RT-PCR, data are expressed as the mean ± SEM and analysed using one-way ANOVA followed by post hoc Turkey’s test. ***; P<0.001: significant difference when compared to the control group, #; P<0.05, and ##; P<0.01: significant difference when compared to CPZ+Veh group. CC; Corpus collosum, CPZ; Cuprizon, Veh; Vehicle, FA; Ferulic acid, HPRT; Hypoxanthine phosphoribosyltransferase 1 and R.

Fig 4

The effect of different doses of FA on mRNA expression of the genes involved in myelination. Data are expressed as the mean ± SEM and analysed using one-way ANOVA followed by post hoc Turkey’s test. *; Significant difference when compared to the control group, #; Significant difference when compared to CPZ group, *; P<0.05, #; P<0.05, **; P<0.01, and ##; P<0.01.