不同游泳训练方式对大鼠下丘脑室旁核c-fos表达的影响

Effects of different swimming styles on the expression of c-fos in the hypothalamic paraventricular nucleus of rats

为了观察游泳运动后大鼠下丘脑室旁核(PVN)内c-fos mRNA及Fos免疫阳性神经元的表达变化,探讨下丘脑PVN对不同形式运动的调节机制,本实验将60只雄性SD大鼠随机分为对照组(n=10)和运动组(n=50),建立大鼠游泳运动模型(持续训练和间歇训练)。在运动结束后0、0.5、1、2、4h等不同时间点,冰水浴分离新鲜脑组织或用多聚甲醛灌注固定取脑,前者经RT-PCR反应,半定量分析运动后下丘脑PVN内c-fos mRNA的含量变化,后者经冰冻切片、免疫组织化学染色,观察Fos免疫阳性神经元的定位和分布情况。结果显示:(1)对照组大鼠下丘脑PVN内c-fos mRNA表达极低,而运动结束后c-fos mRNA表达明显升高。持续运动组逐渐升高,1h时达到最大值;间歇训练结束后2h,c-fos mRNA表达最强,然后回落,运动结束4h组c-fos mRNA仍较对照组显著增多(P<0.05);(2)运动大鼠Fos免疫阳性神经元的数目明显增多,特别是在PVN处。在室旁核小细胞部(pPVN),持续组游泳结束后1hFos阳性神经元的数目显著升高达峰值,而间歇组在运动结束后2h达峰值,同一时刻间歇组的表达高于持续运动组;室旁核大细胞部(mPVN)内,持续组Fos阳性神经元数在运动结束后持续升高,2h后显著下降,而间歇组各时刻阳性神经元的表达变化无统计学差异(P>0.05)。以上结果提示,下丘脑PVN在运动后机体调节中起重要作用,不同的运动方式可以产生不同的影响,且pPVN对不同形式运动性应激反应具有较高灵敏度。

To observe the expression of c-fos mRNA and Fos immunoreactive neurons in hypothalamic paraventracular nucleus （PVN） of adult rats after swimming, and investigate the regulatory mechanism of hypothalamic PVN to different types of exercise, sixty SD rats were divided into the experimental group （n = 50 ） and control group （n = 10）. The model rats were established by durative and intermittent swimming in the present study. The fresh cerebral tissues were obtained by ice water bath or by the paraformaldehyde perfused at 0, 0.5, 1, 2, 4 h after swimming. The former cerebral tissues were detected by RT-PCR in order to investigate the changes of c-fos mRNA in hypothalamic PVN after swimming; the later perfused brains were used to make frozen section and immunohistochemical stained, then the localization and distribution of Fos immunopositive neurons were observed. The results showed that ： （ 1 ） The expression of c-fos mRNA was extremely lower in control group, but increased obviously after exercise. The expression of c-fos mRNA increased gradually and reached peak after 1 hour in durative swimming group; whereas in the intermittent swimming, the expression of c-fos mRNA reached peak after 2 hours, then decreased gradually, but the expression of c-fos mRNA retains the high level after 4 hours compared with control group （P 〈 0. 05 ） ; （2） The number of Fos immunopositive neurons increased significantly in swimming group, especially in hypothalamic PVN. In parvacellular part of PVN （ pPVN）, the number of Fos immunopositive neurons increased to the peak at 1 hour after durative swimming, but at 2 h after intermittent swimming. The number of Fos immunopositive neurons in intermittent swimming was more numerous than that in durative at the same time. In magnocellar part of PVN （mPVN） , the Fos immunopositive neurons increased gently and then decreased at 2 h in durative swimming group, however, the number change of Fos immunupositive neurons between various groups of the intermittent swimming had no statistic difference （ P 〉 0.05 ）. The above results suggest that hypothalamus PVN play an important role in physical regulation after exercise ; the type of different training can lead to different impact and the pPVN is more sensitive to different types of exercising stress response.