ABSTRACT
BACKGROUND: Noise acts as a stressor and is reported to have impact on individual health depending on nature, type, intensity and perception. Modern medicine has no effective drugs or cure to prevent its consequences. Being an environmental stressor noise cannot be avoided; instead minimizing its exposure or consuming anti-stressor and adaptogens from plants can be considered. OBJECTIVES: The present study was carried out to evaluate the anti-stressor, adaptogen and immunostimulatory activity of Scoparia dulcis against noise-induced stress in Wistar rat models. MATERIAL AND METHODS: Noise stress in rats was created by broadband white noise generator, 100 dB A/4 h daily/15 days and S. dulcis (200 mg/kg b.w.) was administered orally. 8 groups of rats were used consisting of 6 animals each; 4 groups for unimmunized and 4 groups for immunized. For immunization, sheep red blood cells (5 × 109 cells/ml) were injected intraperitoneally. RESULTS: Sub-acute noise exposed rats showed a significant increase in corticosterone and IL-4 levels in both immunized and unimmunized rats whereas lymphocytes, antibody titration, soluble immune complex, IL-4 showed a marked increase with a significant decrease in IL-2, TNF-α, IFN-γ cytokines only in unimmunized rats. Immunized noise exposed rats presented increased leukocyte migration index and decreased foot pad thickness, IL-2, TNF-α, IFN-γ with no changes in the lymphocytes. CONCLUSION: S. dulcis (SD) has normalized and prevented the noise induced changes in cell-mediated and humoral immunity and it could be the presence of anti-stressor and immuno stimulant activity of the plant.
ABSTRACT
Noise pollution is one of the most widespread and fast growing environmental and occupational menaces in the modern era. Exposure to noise above 100dB is not adaptable through the brain homeostatic mechanism. Yet, the detrimental effects of noise have often been ignored. Developing reliable animal models to understand the neurobiology of noise stress and advance our research in the field of medicine to impede this growing stressor is needed. In this study experimental animals were divided into four groups, (i) Control and (ii) S. dulcis extract (200mg/kgbw) treated control group. (iii) To mimic the influence of noise, animals in this group were exposed to noise stress (100dB/4h/day) for 15days and finally, (iv) Noise exposed treated with S. dulcis extract (200mg/kgbw) group. Rota-rod and narrow beam performance results showed impaired motor co-ordination in noise exposed group on both 1st and 15th day when compared to controls. This impaired motor function on exposure to noise could be attributed to the altered norepinephrine, dopamine and serotonin levels in both the striatum and cerebellum. Moreover, the motor impaired associated changes could also be attributed to upregulated nNOS and iNOS protein expression in the cerebellum resulting in increased nitric oxide radical production. This increased reactive free radicals species can initiate lipid peroxidation mediated changes in the cerebellar Purkinje cells, which is responsible for initiating inhibitory motor response and ultimately leading to impaired motor co-ordination. Treatment with S. dulcis extract (200mg/kgbw) could control motor impairment and regulate neurotransmitter level as that of control groups when compared to noise exposed group. One key aspect of therapeutic efficacy of the plant could have resulted due to attenuated lipid peroxidation mediated damages on the cerebellar Purkinje cells thereby regulating motor impairment. Thus, targeting the antioxidant and free radicals scavenging properties of the plant could serve as a potential therapeutic to combat this environmental stressor.
