ABSTRACT
Traumatic brain injury (TBI) has been the result of neurological deficit and oxidative stress. This study evaluated the antioxidative neuroprotective property and learning and memory-enhancing effects of dimethyl sulfoxide (DMSO) in a rat model after the induction of TBI. 21 albino rats with 7 rats per group were used in this study. Group I was induced with TBI and treated with DMSO at 67.5 mg/kg orally once daily which started 30 min after the induction of TBI and lasted 21 days. Group II was induced with TBI but not treated while Group III was neither induced with TBI nor treated. Assessment of behavioral function (Learning and memory, anxiety and motor function), the level of an antioxidant enzymes and their gene expression (superoxide dismutase, catalase, glutathione peroxidase), the biomarkers of oxidative stress (malondialdehyde) and S100B levels as well as brain tissues histological studies were conducted. Administration of DMSO to rats with induced TBI has improved learning and memory, locomotor function and decreased anxiety in Group I compared to Group II. Moreover, the level of S100B was significantly (p < 0.05) lower in Group I compared to Group II. Treatment with DMSO also decreased lipid peroxidation significantly (p < 0.05) compared to Group II. There exists a significant (p < 0.05) increase in CAT, SOD, and GPX activities in Group I compared to Group II. Therefore, DMSO has demonstrated a potential antioxidative neuroprotective effect through its ability to increase the level of antioxidant enzymes which they quench and inhibit the formation of ROS, thereby improving cognitive functions.
ABSTRACT
BACKGROUND: Chronic morphine stimulates prolonged stimulation of opioid receptors, especially µ-opioid subtype (MOR), which in turn signals cellular adaptation. However, the sudden termination of the use of morphine after chronic intake causes the withdrawal syndrome. OBJECTIVES: Hence, this study was designed to find an alternative treatment for morphine withdrawal using the alkaloid leaf extract of Erythroxylum cuneatum (E. cuneatum) for the treatment of morphine-exposed neuroblastoma cell lines. METHODS: SK-N-SH, a commercialised neuroblastoma cell line, was used in two separate study designs; the antagonistic and pre-treatment of morphine. The antagonistic treatment was conducted through concurrent exposure of the cells to morphine and E. cuneatum or morphine and methadone for 24 hrs. The pre-treatment design was carried out by exposing the cells to morphine for 24 hrs, followed by 24 hrs exposure to E. cuneatum or methadone. The cytosolic fraction was collected and assessed for proteins expression involved in cellular adaptation, including mitogen-activated protein (MAP)/extracellular signal-regulated (ERK) kinase 1/2 (MEK 1/2), extracellular signalregulated kinase 2 (ERK 2), cAMP-dependent protein kinase (PKA) and protein kinases C (PKC). RESULTS: The antagonistic treatment showed the normal level of MEK 1/2, ERK 2, PKA and PKC by the combination treatment of morphine and E. cuneatum, comparable to the combination of morphine and methadone. Neuroblastoma cells exposed to morphine pre-treatment expressed a high level of MEK 1/2, ERK 2, PKA and PKC, while the treatments with E. cuneatum and methadone normalised the expression of the cellular adaptation proteins. CONCLUSION: E. cuneatum exerted anti-addiction properties by lowering the levels of cellular adaptation proteins it's effects is comparable to that of methadone (an established anti-addiction drug).