前庭代偿过程中前庭传出性和传入性神经系统的相互作用

Mutual interaction of vestibular afferent nervous system and vestibular efferent nervous system in vestibular compensation

目的通过前庭代偿的动物模型,了解在前庭病变的情况下,前庭传出性和传入性神经系统的相互作用。方法动物模型A组(16只)为正常大鼠。B组(15只)左侧前庭损毁术后7d。C组(7只)术后3个月。D组(7只)前庭代偿后。检测两侧头长肌静息状态的肌电图。检测传出性前庭神经系统降钙素基因相关肽免疫组化。检测传出性前庭神经系统胆硷乙酰转移酶(cholineacetyltransferase,AChT)免疫组化。检测传入性前庭神经系统NaKATP酶活性。结果损伤同侧肌群肌电活动减弱、对侧肌群增强,前庭代偿期恢复对称性。急性期传出性前庭神经系统降钙素基因相关肽阳性细胞双侧性增多,活性增高。传出性前庭神经系统损伤同侧AChT阳性反应细胞减少,两侧反应程度增加。前庭代偿期对侧反应程度显著增加。急性期同侧NaKATP酶mRNA表达水平低,对侧前庭信号增强,在前庭代偿期,同侧NaKATP酶mRNA表达水平增强,与对侧一致或略强。结论传出性前庭神经系统可能抑制对侧前庭传入信息,调整同侧前庭中枢兴奋性,在前庭代偿的复杂机制中发挥作用。

Objective To study the mutual interaction of vestibular afferent nervous system and vestibular efferent nervous system in vestibular compensation. Methods Build up animal model of vestibular compensation by destroying single side vestibule of wistar rat. In the study the rats were divided into 3 groups: Group A 16 normal rats; Group B 15 rats, after 7 days of left vestibular damage; Group C 7 rats 3 months after left vestibular damage; and Group D 7 rats, after vestibular compensation. Electromyography of the rats was recorded and the expression of calcitonin gene relative peptide (CGRP), choline acetyltransferase (AChT) and Na-K-ATPase were investigated in efferent vestibular nervous~ system. Results Electric potential activity of muscles of injury side decreased while that of the opposite side increased. In animals of vestibular compensation electric potential of bilateral musculus longus capitis at quiescent stage recovered symmetrically. CGRP positive cells of efferent vestibular nervous system increased bilaterally, and their activity enhanced, especially obvious at the acute stage. AChT positive cells of injury side of efferent vestibular nervous system decreased,but reaction degree of two sides enhanced. Reaction degree of the opposite side enhanced obviously at the stage of vestibular compensation.Expression of Na-K-ATPase mRNA of the same side was lower, but vestibular signal of the opposite side enhanced, clinically head and neck inclined obliquely by means of medial fasciculus of tractus vestibulospinalis. Months later, vestibular signal of the same side enhanced, and that of the opposite side enhanced also, clinical symptoms improved slightly. At the vestibular compensation stage, expression of Na-K-ATPase mRNA of the same side enhanced, and it was same as that of the opposite side or much higher , clinically it reached vestibular compensation. Conclusion Comprehensive effect of the above results maybe as follows : Efferent vestibular nervous system inhibited afferent signal of the opposite vestibule, and it modulated excitement of vestibular center of the same side, and it worked in the complicated mechanisms of vestibular compensation.CGRP may have facilitation function to the vestibular afferent signal of injury side. While Ach improved vestibule compensation by means of inhibition of vestibule excitement of the healthy side.