The Influence Of Nestin Expression On Functions Of The Basal Forebrain Neurons

Objective There is a group of nestin immunoreactive cholinergic neurons in the basal forebrain, but the functional significance of nestin expressing in neurons is not clear. This research studied changes of the basal forebrain nestin positive and negative cholinergic neurons after lateral ventricle injection of colchicine, so as to explore functional influence of nestin expressing on basal forebrain neurons and related possible mechanism.Method Fifty-six mature healthy female SD rats were used in the experiment.The rats were divided into 7 groups, that is, normal control group and colchicine injection groups sacrificed 24 h, 48 h, 3d, 7d, 14 d and 28 d after colchicine jnjection.Each group contains 8 rats. Colchicine injection groups injected 1% colchicine 10μl into left cerebral ventricle with micro injector according to rat brain stereotaxic atlas written by Paxinos and Watson. Injections performed 0.8 mm behind bregma,1.5 mm left to the midline and 4.65 mm in deep. 24 h, 48 h, 3d, 7d, 14 d and 28 d after injection,rats were perfused with paraformaldehyde for fixation. Brains were harvested. Then,frozen section and immunohistochemistry of choline acetyltransferase(Ch AT) and nestin were performed. The number of the Ch AT immunoreactive(Ch AT+) and nestin immunoreactive(nestin+) neurons of basal forebrain medial septum(MS),vertical limb(v DB) and horizontal(h DB) limb of diagonal band nucleus were counted. The number of nestin negative(nestin-) cholinergic neurons was get by minus the numer of nestin+ neurons from Ch AT+ neurons. Then, the numbers of nestin+ and nestin- cholinergic neurons in the basal forebrain at different time points after injection were compered.Results nestin+ neurons distributed in MS, v DB and h DB, which formed a continuous cell band, and distributed in accordance with Ch AT+ neurons. 24 h after colchicine injection, the numbers of nestin+ and nestin- neurons in MS, v DB and h DB of the basal forebrain decreased sharply, There were significantly different from thoseof the normal control group(P<0.01), but no significant difference between the numbers of nestin+ and nestin- neurons(P>0.05). With the passage of time the number of nestin+ neurons recovered gradually, but the number of the nestincholinergic neurons maintained at a lower level. 14 d after colchicine injection,nestin+ neurons were returned to normal levels. They was not significant difference compared with normal control group(P>0.05), but there was significant difference between nesin+ and nesin- neurons(P<0.01).The nesin- neurons were significantly different(P<0.01) between colchicine injection groups and the normal control group at different time points after injection.Conclusion The nestin+ and nestin- cholinergic neurons of basal forebrain were sharply decreased after intracerebroventricular colchicine injection. The nestin+neurons could increase gradually after reduction, but the nestin- neurons were not restored. Compared with the nestin- neurons, nestin+ neurons have stronger neural plasticity.