Early Alterations of Endothelial Nitric Oxide Synthase Expression Patterns in the Guinea Pig Cochlea After Noise Exposure. (November 2019)

• Record Type: Journal Article
• Authors: Heinrich, Ulf R.; Schmidtmann, Irene; Meuser, Regina; Ernst, Benjamin P.; Wünsch, Desiree; Siemer, Svenja; Gribko, Alena; Stauber, Roland H.; Strieth, Sebastian
• Is Part Of: Journal of histochemistry and cytochemistry. Volume 67:Number 11(2019:Nov.)
• Page Start: 845
• Page End: 855
• Publication Date: 2019-11
• Subjects: eNOS -- NO -- noise-induced hearing loss (NIHL) -- otoprotection -- reticular lamina; Histochemistry -- Periodicals; Cytochemistry -- Periodicals; Histocytochemistry -- methods; Histological Techniques; 572.05
• DOI: 10.1369/0022155419876644
• Languages: English
• ISSNs: 0022-1554

Abstract

Constitutively expressed endothelial nitric oxide synthase (eNOS) is supposed to play a role in noise-induced nitric oxide (NO)-production. It is commonly known that intense noise exposure results in inducible NOS (iNOS) expression and increased NO-production, but knowledge about a contribution of the eNOS isoform is still lacking. Effects of noise exposure on eNOS immunolabeling were determined in male guinea pigs ( n =24). For light microscopic analysis, 11 animals were exposed to 90 dB for 1 hr and 6 animals were used as controls. After exposure, eNOS immunostaining was performed on paraffin sections, and the staining intensities were quantified for 4 cochlear regions. For electron microscopic analysis, 2 animals were exposed for 2 hr to 90 dB and 5 animals were used as controls. The intensity of eNOS immunolabeling was found to be already comprehensively increased 1 hr after noise exposure to 90 dB. At the ultrastructural level, a clear increase in eNOS immunolabeling was found in microtubules-rich areas of cochlear cuticular structures. Hence, our findings indicate that the reticular lamina forming the endolymph–perilymph barrier at the apical side of the organ of Corti is involved in a fast intrinsic otoprotective mechanism of the cochlea.