The effect of curcumin on cellular senescence in rats' hippocampus and subventricular zone

Since the aging of the world population increased incidence of neurodegenerative diseases and dementia, researchers focused on this issue. Cellular senescence means the whole biological and genetic changes occurring in aging cells. For centuries mankind has been in search of immortality and has carried out researches effort to delay aging and death. Recently, investigations have been focused on curcumin (CUR) that has strong antioxidant and neuroprotective properties. This study was designed to investigate the effect of CUR treatment on cellular senescence of the cells in hippocampus and subventricular zone. In the study forty-eight male Wistar rats were divided into three groups. Each group were divided into two subgroups consisting of 6 and 12 months old rats. Rats in groups 1, 2 and 3 were administered 300 mg/kg CUR, vehicle and saline respectively intraperitoneally once daily for 6 weeks. At the end of the study the rats were sacrificed under ether anesthesia, blood samples were taken and the whole brain were removed. The brain samples were evaluated histologically with immunohistochemical staining by light microscopy. Superoxide dismutase, glutathione peroxidase activity and malondialdehyde (MDA) levels from the blood and brain samples were analyzed. In CUR-treated groups (Group 1A-B) hippocampal neuronal density and neural stem cells (NSC) in subventricular zone (SVZ) increased significantly (p <0.05) and MDA levels in brain had a statistically significant decrease (p<0.05). In the 12-month CUR subjects' group (Group 1B) compared with other groups in the same age (Group 2B- 3B), the senescent cells in SVZ reduced significantly (p<0.05). As a result, during the aging process CUR treatment might slow down the hippocampal neuronal senescence and might be effective of increasing the number of NSC by slowing down NCS' senescence in SVZ by reducing brain MDA levels. Based on these data, CUR might be a promising agent for preventing cognitive aging and associated neurodegenerative diseases that emerging with advanced age. Keywords: hippocampus, cellular senescence, cellular aging, curcumin, neural stem cell, subventricular zone