Experimental Comparative Study of potential anxiolytic effect of Vitamin C and Buspirone in rats

Abstract

Background: Anxiety disorders are the most common of all mental health problems. They are more prevalent among women than among men, and they affect children as well as adults. The aim of the current study is to evaluate this problem via an experimental animal model and try to explore its possible mechanisms by studying the effect of Vitamin C compared to Buspirone on anxiety in rats induced by Monosodium Glutamate (MSG).

Materials and Methods: 56 healthy adult male albino rats (Sprague-Dawley) weighing 200-250 gm were used and divided into 7 groups (8 rats each). The first and the second groups were provided with normal saline and MSG at a dose of (2 mg/g p.o.) respectively. The other five groups were given MSG and treated daily in the following way: The third and fourth groups were treated with Vitamin C (100, 200 mg/kg p.o) respectively. The fifth group was treated with only Buspirone (10 mg/kg p.o.), while the last sixth and seventh groups were given a combination of Buspirone and Vitamin C with (100, 200 mg/kg) respectively. After 3 weeks, the open field and successive alleys tests were used to assess behavioral changes. The percentage change of systolic blood pressure (SBP) was measured. Additionally, glutathione reductase (GR), malondialdehyde (MDA), and corticosterone levels were determined biochemically.

Results: The results after 3 weeks revealed that MSG group showed significant anxiogenic effects in both behavioral tests, with an increased percentage change of SBP in addition to increased malondialdehyde and corticosterone level measured statistically. While the results of the treated groups revealed that the Vitamin C (100mg/kg) treated group demonstrated significant improvement in anxiety levels in the open field test, there were no significant changes in the biochemical assessment. However, vitamin C (200mg/kg) treated group revealed a significant anxiolytic effect in behavioral tests, improved glutathione and malondialdehyde with low corticosterone level. Administration of buspirone revealed significant anxiolytic effects, which is lower than that of vitamin C (200mg/kg). But it caused significant increase in the oxidative stress and corticosterone levels. A combination of buspirone with Vitamin C (200mg/kg) only demonstrated significant anxiolytic effect in both tests and a significant decrease of corticosterone.

Conclusion: MSG has neurotoxic effect leading to anxiogenic behaviors in rats which are opposed by Vitamin C. Furthermore, as an antioxidant, vitamin C protects against the oxidative stress induced by MSG. Moreover, it lowers the high corticosterone level associated with MSG or buspirone administration.

Key Words: MSG, vitamin C, buspirone, glutathione reductase, malondialdehyde, open field, successive alleys