Assessment of the effects of Zincum metallicum in maternal deprivation-induced behavioral disturbances in female rats

ABSTRACT

Background: Clinical studies have shown that adverse events in early life are quite stressful and can lead to the development of psychiatric disorders, such as anxiety, in adolescence and adulthood in humans. Experimental models of maternal deprivation (MD) in rats can be a useful tool for the understanding how these events in the early period of development can lead to behavioral changes in adulthood. Aims: The objective of this study was to evaluate the long-term effects of Zincum metallicum (Zinc met) homeopathic treatment in rats subjected to maternal deprivation (MD) in their early days of life. Methods: Newborn female rats were subjected to MD during 10 days, one hour per day, from PND10 to PND21, and treated from the 10th day of lactation (PND10) up to weaning (PND21). On the PND21 the rats were divided in 4 groups (N=8) a) treated with Zinc met 30c; b) treated with Zinc met 6c; c) treated with 10% hydroalcoholic solution (HS); and "blank control", rats without any treatment nor experienced deprivation (ND). The medicines were administered in blind trials, identified by codes. The animals were weighed weekly, from weaning until the end of the experiment, and evaluated in the Open Field (OF) and in the Elevated Plus Maze (EPM) devices, to evaluate mobility, emotionality and anxiety, in 3 moments of life in PND21 (childhood), during puberty (PND 40) and adulthood (PND75). Data were analyzed statistically by ANOVA, followed by the Bonferroni's Multiple Comparison Test, being p≤0.05. Results: 1) relative to ND group the Zinc met 6c showed reduced body weight while no differences were observed between the other groups; 2) In the OF, the MD group showed increased rearing behavior at PND 40. The Zinc met 6c group reversed this effect showing similar profile as the ND group. Moreover, Zinc met 6c group showed increase in the immobility time at this age; 3) In the EPM, the MD group showed increased time in closed arms and decreased head dips relative to ND group in PND21 period of observation. Treatment with Zinc met 6c but not with Zinc met 30c was effective to reduce this anxiety-like behavior in PND21. Conclusion: According to the proposed model, Zincum metallicum 6c seems to be able to prevent in anxiety-like behavior induced by maternal deprivation in the childhood, mainly in behavioral models related to anxiety. However, other studies still need to be developed to understand the physio-pathological basis of these effects. (AU)