Effects of fastigial nucleus electrical stimulation on lateral ventricle nestin expression after focal cerebral ischemia/reperfusion in adult rats

Yanjun Huang; Yong Luo

摘要：BACKGROUND: Previous studies have confirmed that fastigial nucleus electrical stimulation can induce endogenous neuroprotective mechanisms and produce wide and long-lasting neuroprotective effects. Nevertheless, the precise mechanisms remain poorly understood. OBJECTIVE: This study was designed to observe the effects of fastigial nucleus electrical stimulation on nestin-positive cell expression in adult rat lateral ventricle after focal cerebral ischemia/reperfusion, as well as neurological functional changes as a function of time.DESIGN: A randomized controlled animal experiment. SETTING: Department of Neurology, First Affiliated Hospital of Chongqing Medical University; Chongqing Key Laboratory of Neurology.MATERIALS: This study was performed in the Department of Neurology, First Affiliated Hospital of Chongqing Medical University and Chongqing Key Laboratory of Neurology from September 2004 to February 2006. A total of 180 healthy, adult, male Wistar rats, aged 8 weeks old, were provided by the Laboratory Animal Center of Chongqing Medical University. The main reagents and equipments were as follows: rabbit anti-rat nestin monoclonal antibody (Wuhan Boster Company, China).MAIN OUTCOME MEASURES: Nestin-positive cells were detected by immunohistochemical staining in the rat ischemic lateral cerebral ventricle at 1, 3, 7, 14, 21, and 28 days post-reperfusion. RESULTS: Morphological changes of nestin-positive cells in the ischemic lateral ventricle: in the normal control group, very few nestin-positive cells were detected in the choroid plexus, ependyma, and subependymal region of the lateral ventricle. In the model group, the number of nestin-positive cells exhibited a tendency towards a single peak, i.e., cells increased at day 1, reached peak levels by day 7, and then decreased sharply. Fastigial nucleus electrical stimulation was administered following focal cerebral ischemia/reperfusion, and results revealed that nestin-positive cell morphology was similar to horizontal cell morphology on day 7. The number of nestin-positive cells decreased after 14 days; however, the proportion of horizontal cell-like cells increased. In the sham-stimulation group, there was no change in nestin-positive cells. nestin-positive cell expression in the ischemic lateral ventricle: nestin-positive cell expression increased in the ischemic lateral cerebral ventricle, exhibiting a tendency towards unimodality; the number of cells peaked on day 7 (P < 0.01) and gradually decreased after 14 days (P < 0.01). Following fastigial nucleus electrical stimulation, the number of nestin-positive cells increased significantly (P < 0.05-0.01), reached peak levels by day 7 (P < 0.01), and remained at very high levels after 14 days (P < 0.01). Neurofunctional changes: neurofunctional deficits were gradually alleviated with prolonged focal cerebral ischemia/reperfusion time. At 1 hour of ischemia, and 6 hours to 7 days of reperfusion, rat neurological scores were significantly lower in the stimulation group than in the model and sham-operation groups (P < 0.05-0.01).CONCLUSION: Fastigial nucleus electrical stimulation increased nestin-positive cells in the rat lateral ventricle after focal cerebral ischemia/reperfusion in a time-dependent manner and simultaneously improved neurological deficits, as well as promoted differentiation of nestin-positive cells towards a cell type with neuronal and neuroglial cellular morphology.