Effect of water restrictions on the physiological parameters, psychological behavior and brain c-Fos expression in rats.
Effect of water restrictions on the physiological parameters, psychological behavior and brain c-Fos expression in rats.
复制标题
限水对大鼠生理参数、心理行为及脑c-Fos表达的影响。
作者：
Zheng;Bai;Q. Tan;X. Duan;F. Kuang;Zhen Xu;G. Ju
目的
为探讨生理性和心理性应激源引起的应激反应特点，观察并比较了不同实验模式下限水对大鼠生理指标、心理行为表现和脑c-Fos表达的影响。
方法
选用雄性Wistar大鼠58只，随机分为3个实验组（n = 18）和对照组（n = 4）。对照组大鼠在实验期间自由饮水。在实验组中，限制对大鼠的供水。定时供水（TW）组，每天定时供水2次，每次10 min。在空瓶供应（EB）和限水（WR）组中，每天仅在清晨或傍晚供应水一次，每次10 min，并且在预定的供水时间点，在EB组中仅提供不含水的空瓶，而在WR组中不提供任何水。每天观察饮水量、进食量、体重增加情况及行为评分。分别于限水后3、7、14 d固定灌流，测定血清皮质酮水平，每组各6只。免疫组化法检测脑组织c-Fos表达。
结果
体重增长减慢，血清皮质酮水平升高，出现探索、攻击等不平静躁动的心理行为表现，穹窿下器（SFO）、正中视前核（MnPO）、最后区（AP）、下丘脑室旁核（PVN）、视上核（SON）、EB组和WR组杏仁内侧核（MeA）、中央核（CeA）和腹外侧隔（LSV）Fos表达均较对照组明显减少，孤束核（NTS）Fos表达减少。EB组多数核团Fos表达于第3天开始变化，至少持续到第7天，第14天下降; WR组多数核团Fos表达于第7天开始变化，第14天达到高峰。TW组除第7天皮质酮浓度略有升高外，其余指标无变化。
结论
结果表明，限水诱导生理和心理应激反应。并且以不同模式实验性地执行的水限制导致行为反应的不同表现和离散脑核/区域中的脑立即早期基因表达。
OBJECTIVE
In order to characterize the feature of stress response induced by stressor with both physical and psychological natures, the effects of water restriction performed in different experimental modes on the physiological parameters, psychological behavioral manifestations and brain c-Fos expressions were observed and compared.
METHODS
Fifty-eight male Wistar rats were used and randomly divided into three experimental groups (n = 18 for each) and a control group (n = 4). In control group, the rats were allowed to access drinking water freely at all experimental period. In the experimental groups the water supply to the rats was restricted. In timed water supply (TW) group, the water was supplied twice a day, 10 min for each in fixed hours every day. In empty bottle-served (EB) and water-restricted (WR) groups, the water was served only once a day for 10 min, either in the early morning or evening, and in the other time point scheduled for water supply only an empty bottle without water was provided in the EB group and nothing was given in the WR group. The quantities of drank water and eaten food, weight-gaining, and behavior score were observed every day. The serum level of corticosterone was assayed and the rats were sacrificed with fixative perfusion of 3 d, 7 d or 14 d, respectively, following water restriction (n = 6 for each time point in each group). The brain c-Fos expressions were examined with immunohistochemical method.
RESULTS
The slow down of weight-gaining, rise of serum corticosterone level, occurrence of psychological behavioral manifestations of unpeaceful restlessness such as exploring and attacking, enhance of c-Fos expression in the subfornical organ (SFO), median preoptic nucleus (MnPO), area postrema (AP), hypothalamic paraventricular nucleus (PVN), supraoptic nucleus (SON), medial (MeA) and central (CeA) amygdaloid nucleus and ventrolateral septum (LSV) were noticed in both EB and WR groups, except the nucleus of solitary tract (NTS) in which the Fos expression was decreased. The changes of Fos expression in most of nuclei in EB group began at day 3, at least persisted till day 7, and backed down at day 14, while in WR group, similar changes started at day 7 and reached its peak at day 14. In TW group, only the concentration of corticosterone at day 7 was slightly increased and the rest indexes observed were unchanged.
CONCLUSION
The results indicate that water restriction induces physical as well as psychological stress responses. And the water restrictions experimentally executed in different modes result in different manifestations of behavioral response and brain immediately early gene expression in discrete brain nuclei/regions.