MAPK通路对急性冷暴露大鼠下丘脑细胞增殖活性的调控作用

目的观察-15℃急性冷暴露4 h及室温复温24 h对大鼠下丘脑细胞增殖活性的影响及MAPK通路在此过程中的调控作用。方法雄性SD大鼠9只,体重(230±10)g,随机平均分为室温对照组(n=3)、冷暴露组(n=3)和冷暴露并复温组(n=3)。观察每组大鼠下丘脑神经元细胞增殖水平及MAPK通路活性的变化。结果冷暴露4 h导致大鼠中心体温显著降低(P<0.05),复温24 h后,中心体温恢复至冷暴露前水平;大鼠下丘脑Ki67表达水平和JNK磷酸化水平在急性冷暴露4 h后显著升高(P<0.05),室温复温24 h后下降至基线水平。ERK2磷酸化水平在急性冷暴露4h后显著升高(P<0.05),室温复温24 h后磷酸化水平与对照组相比明显降低(P<0.05)。结论急性冷暴露引起的中心体温下降导致大鼠下丘脑增殖活性增加,MAPK通路可能参与了这一过程的调控。

Regulation of Proliferative Activity of Hypothalamic Cells by MAPK Pathway in Rats with Acute Cold Exposure

Objective To determine the effects of acute cold extxsure （ - 15℃, 4 h） and subsequent rewarming （room temperature, 24 h） on proliferative activity of hypothalamic cells and the regulative role of mitogen- activated protein kinase （MAPK） pathway in this process. Methods Nine male adult Sprague - Dawley rats （weighting 230 ±10 g） were assigned to three groups randomly, room temperature control group （ n = 3）, acute cold exposure group （n = 3） and acute cold exposure with subsequent rewarming group （n = 3）. The proliferation level of hypothalamic neurons and the changes of MAPK pathway in each group were determined. Results The core body temperature of rats significantly declined after acute cold exposure （P 〈 0.05） and returned to baseline after rewarming. The expression of Ki67 and phosphor - JNK in hypothalamus increased significantly af- ter acute cold exposure （P 〈 0.05） and returned to control level after rewarming. The expression of phosphor - ERK2 also in- creased significantly after acute cold exposure （P〈0.05）, but decreased to a level significantly lower than that of controls after rewarming （P〈0.05）. Conclusions Decrease of core body temperature due to acute cold exposure leads to increase of prolif- erative activity in hypothalamus neurons. MAPK pathway may play roles in regulating this process.