Beneficial Effect of Chronic Treatment with Extracts from Rhodiola Rosea L. and Curcuma Longa L. on the Immunoreactivity of Animals Subjected to a Chronic Mild Stress Model

Background: Recent studies have suggested increased levels of pro-inflammatory cytokines in depression. Aim: The present study aimed to evaluate the effect of extracts from Rhodiola and Curcuma on immunoreactivity of animals subjected to a chronic mild stress (CMS) model followed by lipopolysaccharide-induced inflammation. Materials and methods: Male Wistar rats (n=56) divided in 7 groups were treated orally with: distilled water 10 ml/kg (control and CMS model groups); Rhodiola 250 mg/kg; Rhodiola 500 mg/kg; Curcuma 250 mg/kg; Curcuma 500 mg/kg, Rhodiola 250 mg/kg and Curcuma 250 mg/kg. All groups except the control were stressed daily according to a CMS protocol. Changes in glucose preference, weight gain and locomotor activity were recorded. In the sixth week the animals were challenged with LPS and rats’ sera were obtained for ELISA evaluation of TNF-α and IL-6 levels. Results: The animals from the model group decreased their weight gain, glucose preference and locomotor activity compared to controls. The groups exposed to stress and treated with Rhodiola 500 mg/kg, Curcuma 500 mg/kg and their combination increased their locomotor activity compared to the model group. High expression of the pro-inflammatory cytokines TNF-α and IL-6 were found in all groups exposed to CMS and challenged by LPS. Conclusions: The groups exposed to the stress procedure showed a variety of depression-like behavioral changes. In addition, ELISA tests showed that CMS is affecting rats’ immunity by increasing the cytokines’ levels. These changes could be reversed by administration of Rhodiola and Curcuma in combination suggesting synergic interaction regarding their anti-inflammatory and anti-stress effects