雌激素对雌性大鼠舌下神经核及颏舌肌的影响

Effect of estrogen on genioglossus and hypoglossal nucleus of female rats

目的 :研究SD大鼠外周血不同雌激素水平对舌下神经核自发放电及颏舌肌功能的影响,探讨雌激素影响上气道稳定性的中枢途径。方法:将30只SD大鼠随机分为假手术组(sham operation group,Sham)、去卵巢组(ovariectomized group,OVX)及去卵巢+雌二醇回补组(ovariectomized+estrogen covering group,OVX+E2),采用玻璃微电极记录神经元放电,记录舌下神经核自发放电频率和最大幅值。采用BL-420生物学系统,检测颏舌肌功能:颏舌肌肌电的平均频率、最大频率、积分幅度、最大幅度;电刺激诱发肌电幅度、临界融合频率、50%强直收缩时程及阈刺激强度。采用SPSS13.0软件包对数据进行单因素方差分析。结果:OVX组舌下神经核的自发放电频率和最大幅值低于Sham组和OVX+E2组(P<0.05);OVX组颏舌肌肌电最大频率、平均频率、积分幅度和最大放电幅度、50%强直收缩时程低于Sham组和OVX+E2组(P<0.05),OVX组阈刺激强度和临界融合频率均显著高于Sham组和OVX+E2组(P<0.05),OVX+E2组和Sham组各项指标相比无显著差异(P>0.05)。OVX组、Sham组、OVX+E2组颏舌肌的电刺激诱发肌电幅度无显著差异(P>0.05)。结论:外周血雌激素水平影响舌下神经核的兴奋性,进而影响颏舌肌功能。雌激素可能影响颏舌肌的收缩功能及抗疲劳能力。

PUEPOSE： To study the hypoglossal nucleus spontaneous discharge and genioglossus function of SD rats with different estrogen levels, and explore the possible central pathways of estrogen protecting upper airway stability. METHODS： Thirty SD rats were randomly divided into 3 groups： sham operation group （Sham）, ovariectomized group （OVX） and ovariectomized ＋ estrogen covering group （OVX＋E2）. The hypoglossal nucleus spontaneous discharge frequency and maximum amplitude of spontaneous discharge were measured with extracellular recording technique;BL-420 biological was used to detect the genioglossus EMG and contraction. The measurements included the average frequency, the maximum frequency, the integral amplitude, the maximum amplitude of the genioglossus, the amplitude of the evoked EMG, the critical fusion frequency, the 50% tonic contraction, and the intensity of the stimulus. SPSS 13.0 software package was used to analyze the data with One-way ANOVA. RESULTS： The hypoglossal nucleus spontaneous discharge frequency and maximum amplitude of spontaneous discharge in OVX group were significantly lower than the Sham group and OVX＋E2 group （P〈0.05）. The genioglossus EMG maximum frequency, average frequency, amplitude and integral maximum discharge magnitude, 50% tonic contraction drive of genioglossus in OVX group were significantly lower than the Sham and OVX＋E2 group （P〈0.05）; the threshold stimulation strength and critical fusion frequency in OVX group were significantly higher than the Sham and OVX ＋ E2 group （P〈0.05）; there was no significant difference between OVX＋ E2 group and the Sham group （P〉0.05）; there was no significant difference among the three groups （P〉0.05）.CONCLUSIONS： Estrogen changes excitability of hypoglossal nucleus and affect contraction of genioglossus. Estrogen levels can affect genioglossus contraction function and the ability of resistance to fatigue.