Ginger Extract Reduces Chronic Morphine-Induced Neuroinflammation and Glial Activation in Nucleus Accumbens of Rats

BACKGROUND: Chronic usage of morphine elicits the production of inflammatory factors by glial cells and induces neuroinflammation. Ginger (Zingiber Officinale Roscoe) is a medicinal herb that has anti-inflammatory properties. It has been reported that ginger shows anti-addictive effects against chronic usage of morphine; however, its influence on morphine-induced neuroinflammation has not yet been clarified. METHODS: Morphine (12 mg/kg) was administrated intraperitoneally for 6 consecutive days. To evaluate the effect of ginger on morphine-induced neuroinflammation, ginger extract (100 mg/kg) was given orally 30 minutes before morphine. Glial fibrillary acidic protein (GFAP) and p38 mitogen-activated protein kinase (p38 MAPK) levels were assayed by immunoblotting in the rat nucleus accumbens (NAcc). FINDINGS: The injection of chronic morphine increased the levels of proteins involved in neuroinflammation (p38 MAPK and GFAP) in NAcc. Furthermore, the levels of p38 MAPK and GFAP significantly returned to the control levels by ginger extract. CONCLUSION: The results suggest that the ginger extract can reduce morphine-induced neuroinflammation in NAcc.