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

Chronic usage of morphine elicits the production of inflammatory factors by glial cells andinduces neuroinflammation. Ginger (Zingiber Officinale Roscoe) is a medicinal herb that has antiinflammatory properties. It has been reported that ginger shows anti-addictive effects against chronic usageof morphine; however, its influence on morphine-induced neuroinflammation has not yet been clarified. Morphine (12 mg/kg) was administrated intraperitoneally for 6 consecutive days. To evaluate theeffect of ginger on morphine-induced neuroinflammation, ginger extract (100 mg/kg) was given orally 30minutes 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). 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 tothe control levels by ginger extract. The results suggest that the ginger extract can reduce morphine-induced neuroinflammation in NAcc.