Histopathologic effects of methadone on central nervous system of mice newborns in suckling period

Methadone is a synthetic opioid, used in the treatment of opioid dependence and chronic pain. The aim of this study was to investigate histopathological effects of methadone on central nervous system of mice newborns in suckling period. In this study, twenty eight mature pregnant mice were randomly divided into four groups of seven each. Three groups were intraperitonealy injected methadone (3, 6, 9 mg/kg per day respectively) from first lactational day until weaning. Control group was injected distilled water saline. At the 27th day, respectively offspring were weighed and anesthetized with choloroform and then their brains removed from their skulls and immersed in the fixative formalin buffer 10% for 24h and samples were stained with Hematoxylin and Eosin stain for the histopathology study. The data were analysed using one way ANOVA and Sheffe tests. Methadone caused a significant reduction in both weight and Crown Rumpa-Length and also an increase in the brain to body mass ratio in experimental groups compared to the control group (P<0.001). In addition, offsprings who received methadone during lactational period showed changes in the brain neuronal degeneration along with apoptotic cells in the regions of DG and CA3 of the hippocampus. Methadone consumption during lactational period can cause reduction in growth indices and structural disorders in the offspring brains