The subject mice were thymectomized 4 weeks after birth. Ten months after the
thymectomy, learning behaviors in passive and active avoidance performances and a spatial memory task, the contents of brain monoamines and brain
choline acetyltransferase (ChAT) activity, as well as the immune response were evaluated.
DX-9386, a traditional Chinese medicinal prescription consisting of ginseng, polygala, acorus and hoelen, was prepared in CE-2 mouse food (1%, w/w) and given to the thymectomized mice after the operation until all the experiments were finished.
DX-9386 treatment significantly ameliorated the learning and memory ability impaired by
thymectomy in passive avoidance performances and in a spatial memory task, and the mice tended to improve in the active avoidance performance of a lever press test. However,
DX-9386 treatment did not improve the
thymectomy-reduced immune response. The contents of hypothalamic
norepinephrine,
3,4-dihydroxyphenylacetic acid and
homovanillic acid, and hypothalamic ChAT activity were significantly increased in thymectomized mice, and
DX-9386 restored them to the control levels. These results suggested that
DX-9386 mainly affected the cognitive process of the central nervous system to ameliorate the learning and
memory deficit induced by
thymectomy.