The Expression of neuronal Nitric Oxide Synthase in Reinnervated Recurrent Laryngeal Nerve

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J Korean Soc Laryngol Phoniatr Logop > Volume 12(1); 2001 > Article

Journal of The Korean Society of Laryngology, Phoniatrics and Logopedics 2001;12(1): 46-54.

흰쥐에서 편측 반회후두신경 재지배 후 neuronal Nitric Oxide Synthase(nNOS)의 발현과 후두기능회복과의 관계

정성민¹, 김성숙², 조윤희¹, 구태완¹, 박수경¹, 신유리¹

¹이화여자대학교 의과대학 이비인후과학교실²울산대학교 의과대학 병리학교실

The Expression of neuronal Nitric Oxide Synthase in Reinnervated Recurrent Laryngeal Nerve

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ABSTRACT

Background and Objectives
: Nitric oxide(NO) is a short-lived molecule with messenger and cytotoxic functions in nervous, cardiovascular, and immune systems. Among the three distinct NOS isoforms, the neuronal isoform is expressed in small, discrete neuronal populations of CNS and PNS. Axonal injury in adult animals results in a dramatic NOS up-regulation in many types of central and peripheral neurons which normally lack the enzyme or express it only at very low levels. In previous study, we confirmed the efficacy of PEMS on the early functional recovery in rats with surgically transected and reanastomosed recurrent laryngeal nerve. Therefore, after we obtained functionally recovered rats using PEMS in this study, we studied to evaluate the expression of nNOS through the analysis of the difference between functional recovery group and non-recovery group in the recurrent laryngeal nerve.
Materials and Method
: Using 84 healthy male Sprague-Dawley rats, transections and primary anastomosis were performed on their left recurrent laryngeal nerves. Rats were then randomly assigned to 2 groups. The rats in group A(n=42) received PEMS by placing them in custom cages equipped with Helm-holz coils(3 hr/day, 5 days/wk, for 12 wk). The rats in group B(n=42) were handled the same way as the group A, except that they did not receive PEMS. Laryngovideoendoscopy was performed before and after surgery and followed up weekly. Laryngeal EMG was obtained in both PCA and TA muscles. Immunohistochemisty staining using monoclonal anti-neuronal nitric oxide synthase(nNOS) antibody was performed to detect nNOS in recurrent laryngeal nerve and nodose ganglion.
Results
: 20 rats(63%) in group A and 5 rats(17%) in the group B showed recovery of vocal fo1d motion. The number of NOS-positive cells was increased in functionally-recovered rats. NOS-staining intensity was reduced 12 weeks after nerve injury. The difference between PEMS group and non-stimulated group was not found.
Conclusion
: This study shows that nNOS may exert a beneficial effect on nerve regeneration and functional repair.

KEY WORDS： Recurrent laryngeal nerve;Reinnervation;functional recovery;Nitric oxide(NO);Nitric oxide synthase(NOS);S-100 protein;Pulse electromagnetic stimulation;nNOS;S-100;

중심 단어： 반회후두신경;기능회복;