Research Of Changes Of NO And CGRP In Pharyngeal Tissues And Plasma In OSAS

Objective: A narrow pharynx plays an important role in the pathogenesis of OSAS. Lately some reports show that a majority of patients with OSAS had signs of pharyngeal afferent and efferent (motor) nerve lesions, and these lesions might cause the collapse of upper airways with OSAS. So there must be some neurogenic inflammation mediums hi pharyngeal tissues. The purpose of this research is to explore the changes of nitric oxide(NO) and calcitonin gene-related peptide (CGRP) and its potential functions in OSAS, and to discuss the reasons which cause the narrow of pharynx . Materials and Methods: This study investigated the levels of NO and CGRP in plasma of OSAS subjects in the early morning comparing with that of control group, and the effect after UPPP in OSAS subjects. We also investigated the content of NO and CGRP in pharyngeal tissues of OSAS comparing with that of control subjects. Moreover, the distribution of NOS and CGRP in pharyngeal tissues was researched using method of immunohistochemistry , and the histological changes in pharynx of OSAS was observed with light-microscope. Results: (1)Plasma NO level in OSAS subjects was the lowest among the three groups and that in control group was the highest (OSAS = 53.33 +/- 7.83 microM, control subjects = 74.30 +/- 6.40 microM, UPPP group = 68.12 +/- 7.46 microM, P< 0.001). There was a significant increase in plasma CGRP after UPPP(P<0.01), and the plasma CGRP level in control subjects was as high as thatin UPPP group(P>0.05) (OSAS = 48.04 +/- 6.66 microM, control subjects = 54.37 +/- 4.43 microM, UPPP group = 54.10 +/- 3.70 microM). NO level in pharyngeal tissue of OSAS increased significantly (OSAS=0.748+/-0.053 nmol/g, control subjects =0.382+7-0.03 lumol/g P< 0.001), but CGRP level decreased markedly (OSAS=1.566+/-0.279 pg/mg, control subjects =2.685+7-0.351 pg/mg P< 0.001). (2) Pathological changes: Most subepithelia blood vessels and/or in deep part of soft tissues of OSAS expanded and hyperemiaed to some extent, and some small vascular wall thickened and lumen of blood vessel turned to narrow. Most salivary glandular epithelium were mucous epithelium and the cavity of partial duct expanded obviously within a great quantity of mucous substance. Striated muscle cells became degeneration,swelling and atrophy. Neutral mucous substance of PAS(+) was found in salivary glandular epithelium of control group, and acid mucous substance of AB(++) was found in that of OSAS group. (3) Immunohistochemistry change about NOS: There was a feeble positive expression in mucosa squamous epithelium of OSAS and powerful positive expression in some salivary glandular epithelium, striated muscle cells, vascular wall /small vascular wall and epithelium of glandular duct of OSAS. However, there was focal / segment positive marking only in epithelium of glandular duct and striated muscles in control group. (4) Immunohistochemistry change about CGRP: There were diffusible positive markings in striated muscle cells and most cilium columnar epithelium in OSAS, and negative expressions in other sites. Oppositely, there was no marking in interstitial blood vessels and epithelial cells of salivary gland in control subjects, and positive expressions in other sites. Conclusion: (1)Thisstudy demonstrates that circulating NO and CGRP are suppressed in OSAS,and reversible promptly after UPPP. Further more, The content of NO in pharyngeal tissues increases significantly and that of CGRP decreases markedly. (2)The pathological changes of pharyngeal tissues of OSAS are obviously, and the distribution of NOS and CGRP in pharyngeal tissue changes apparently according to sites. (3) Neurogenic inflammation medium may be the production of OSAS and/or may be the reason to worsen the later.