The underlying mechanisms of how nicotine affects cord umbilical cells remain largely elusive. Nicotine rapidly crosses the blood-brain barrier (10 to 20 s) and binds to nicotinic acetylcholine receptors (nAChRs). Nicotine considered as a major compound found in cigarette smoke and the mechanism of nicotine action in immune response is not well understood. Cigarette smoke well known by activation of toll like receptors (TLRs) especially TLR4 and 9 which stimulates the immune response by induction of releases of cytokines mainly CXCL-8 which in turn triggers lungs reactions specially induction of neutrophils recruitments. In this study we isolated human umbilical mononuclear cells (UCBMC) from umbilical cord blood and exposed to the nicotine for detection any cytokines and TLRs modulation. We have found that nicotine (at concentration 0.01µM) induced release of TNF-a and IL-6 but not CXCL-8 production. Besides we have shown that nicotine did not effect on TLR4 surface expression however up-regulated the TLR2 surface expression. Moreover expression of CD11a and CXCR4 after nicotine incubation was upregulated as demonstrated by flow cytometry analysis, These data indicated that nicotine by stimulation of inflammatory cytokines induces immune response. The present study provides evidence that nicotine selectively regulates the release of cytokines and expression of TLRs. Further studies are needed to exploring details of its effects and signaling.

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Background: Methadone is a centrally-acting synthetic opioid analgesic widely used in the methadone maintenance therapy (MMT) programs throughout the world. Considering its neurotoxic effects particularly on the cerebellum, this study aims to address the behavioral and histological alterations in the cerebellar cortex associated with methadone administration. Materials and Methods: Twenty-four adult male albino rats were randomized into two groups of control and methadone treatment. Methadone was subcutaneously administered (2.5–10 mg/kg) once a day for two consecutive weeks. The functional and structural changes in the cerebellum were compared to the control group. Results: Our data revealed that treating rats with methadone not only induced cerebellar atrophy, but also prompted the actuation of microgliosis, astrogliosis, and apoptotic biomarkers. We further demonstrated that treating rats with methadone increased complexity of astrocyte processes and decreased complexity of microglia processes. Our result showed that methadone impaired motor coordination and locomotor performance and neuromuscular activity. Additionally, relative gene expression of TNF-α, caspase-3 and RIPK3 increased significantly due to methadone. Conclusions: Our findings suggest that methadone administration has a neurodegenerative effect on the cerebellar cortex via dysregulation of microgliosis, astrogliosis, apoptosis, and neuro-inflammation.