Anti-Inflammatory Compounds Ameliorate Locomotion and Anxiety Behaviors in Cuprizone Mouse Model of Multiple Sclerosis

¹Rasha Mohammed Alderbi, ¹Gadah Ali Alshahrany, ¹Kholoud Ahmed Alyami, ¹Hadeil Muhanna Alsufiani, ¹Ulfat Mohammed Omar, ¹Maryam A. Al-Ghamdi, ¹Mohammad Z. Alam

¹Department of biochemistry, Faculty of Sciences, King Abdulaziz University, Jeddah, Saudi Arabia

Introduction:

Multiple sclerosis (MS) is an inflammatory, autoimmune disease that affects the central nervous system (CNS). One of the commonly used models to study demyelination and remyelination process involved in MS is Cuprizone (CPZ)-intoxicated mouse model. During the demyelination period, CPZ has been shown to cause impaired locomotion activity and increased anxious behavior in mice. Notably, various compounds have been known for their anti-inflammatory effect on different inflammatory and neurodegenerative diseases in-vitro and in-vivo. These include 6-Shogaol (Sh), Vanillic acid (VA) (4-hydroxy-3-methoxybenzoic acid), and Retinoic acid (RA). Since their anti-inflammatory activities could be regarded as potential treatment/co-treatment for MS disease, this study has been aimed to investigate the therapeutic effect of Sh, VA, and RA on locomotion and anxiety behavior of cuprizone-model mice.

Material(s) and Method(s):

Briefly, 6–8-week-old male SWR/J mice (15-22 g) were used (n=30) and assigned randomly into 5 groups (6 mice/group). Control group has received standard rodent chow during the entire study, while CPZ-intoxicated groups have received 0.3% CPZ-mixed chow for the first 5 weeks to induce demyelination, followed by 4 weeks of standard rodent chow for recovery. During the last 4 weeks, Sh, VA, and RA groups have received intraperitoneal injections of 25 mg/kg Sh, 30 mg/kg VA, and 20 mg/kg RA, respectively. In order to evaluate locomotion and anxiety behaviors, Open Field Test was performed using EthoVision®XT software. Total distance moved (TDM) was calculated as an indicator of locomotion, whereas percentage of time spent in the center was an indicator of anxiety. Firstly, tests were performed in 5th week of the study, where maximum demyelination was achieved, and induction of the disease was confirmed accordingly. After that, the treatment regimens have been started, and the tests were done in 7th week (two weeks after starting treatment) as it represents early spontaneous remyelination. Lastly, the tests were repeated in the 9th week by the end of remyelination progress.

Result(s):

In week 5, all CPZ-intoxicated groups showed a significant decrease in TDM and % time spent in center compared to control group, which insured the induction of the MS before starting treatment. Afterward, TDM of Sh, VA, and RA treated groups were significantly improved in week 7 compared to CPZ group. However, further decrease in % spent in the center of CPZ-intoxicated groups was shown in the same week denoting highly anxious behavior. By week 9, all treated groups exhibited a significant increase in TDM and % spent in the center compared to the CPZ group.

Conclusion(s):

In conclusion, 6-Shogaol, Vanillic acid, and Retinoic acid enhance the locomotor activity and improve anxiety behaviors in the cuprizone mouse model of Multiple sclerosis.