Effects of Gossypium herbaceam Extract Administration on the Learning and Memory Function in the Naturally Aged Rats: Neuronal Niche Improvement1

Aging-associated cognitive impairment is an important health care issue since individuals with mild cognitive impairment are more likely to develop Alzheimer's disease. In the present study, the protective effect of Gossypium herbaceam extracts (GHE) on learning and memory impairment associated with aging were examined in vivo using Morris water maze and step through task. Furthermore, the antioxidant activity and neuroprotective effect of GHE was investigated with methods of histochemistry and biochemistry. These data showed that oral administration with GHE at the doses of 35, 70, and 140 mg/kg exerted an improved effect on the learning and memory impairment in aged rats. Subsequently, GHE afforded a beneficial action on eradication of free radicals without influence on the activity of glutathione peroxidase and superoxide dismutase. GHE treatment enhanced the expression levels of nerve growth factor. Meanwhile, proliferation of neural progenitor cells was elevated in hippocampus after treatment with GHE. Taken together, neurogenic niche improvement could be involved in the mechanism underlying neuroprotection of GHE against aging-associated cognitive impairment. These findings suggested that GHE might be a potential agent as cognitive-enhancing drugs that delay or halt mild cognitive impairment progression to Alzheimer's disease or treatment of aging-associated cognitive impairment.