Deposition Process of Eosinophilic Substance in Mouse Nasal Septum

Abstract

ABSTRACT. An eosinophilic substance is usually observed in the mouse nasal septum, and its volume increases with age. In contrast to descriptions in textbooks defining the eosinophilic substance as amyloid, our previous report revealed that the observed eosinophilic substance is not amyloid, but consisted of collagen and an amorphous material. Furthermore, it was suggested that the amorphous material was produced by the clear hematoxylin and eosin (HE)-stained nasal gland epithelial cells. In this study, we investigated the deposition process of the amorphous material produced by nasal gland epithelial cells in the interstitium morphologically. In most cases, the amorphous materials in the clear HE-stained nasal gland epithelial cells accumulated at the basal portion. Collagen fibers surrounding the nasal glands partially disappeared, whereas the amorphous material in contact with the rough endoplasmic reticulum of the nasal gland epithelial cells continued to the amorphous material in the interstitium. These findings suggested that the amorphous material produced by the clear HE-stained nasal gland epithelial cells migrated to the interstitium through the partial opening of the basement membrane.KEY WORDS: amorphous material, basement membrane, eosinophilic substance, mouse, nasal cavity.J. Vet. Med. Sci. 71 (7): [931][932][933][934][935] 2009 An eosinophilic substance (ES) is usually observed in the mouse nasal septum, and its volume increases with age. ES has been described as amyloid in textbooks [5,7], but there are a few descriptions that ES is not amyloid [4,8]. Our previous report revealed that ES is not amyloid because it reacted negatively to Congo red and there were no nonbranching fibrils in the electron microscope examination [1]. Moreover, ES consisted of collagen and an amorphous material (AM), suggesting that AM is a complex carbohydrate except for the osteoglycan, because ES reacted positively with periodic acid Schiff reaction with prior diastase treatment, and negatively with toluidine blue and alcian blue [1].In the previous study, two kinds of glands were observed in the nasal septum in mice [1]. One of them stained clear with hematoxylin and eosin (HE), the other stained dark with HE. ES deposited at the interstitium of the clear HEstained nasal glands only. Electron microscopically, AM was observed in the clear HE-stained nasal gland epithelial cells as well as in the interstitium [1]. Glands composed of nasal gland epithelial cells holding AM were also observed in areas without interstitial AM nearby. Furthermore, AM was not only very similar to the material in the rough endoplasmic reticulum of the clear HE-stained nasal gland epithelial cells, it was also connected to it. These findings suggested that the clear HE-stained nasal gland epithelial cells produced AM [1].It is not clear how AM produced by clear HE-stained nasal gland epithelial cells deposits in the interstitium. In this study, we investigated the deposition process histopathologically and electron microscopically. MATERI...

Proceedings of the 2013 Joint JSTP/NTP Satellite Symposium

“…Similar lesions were previously diagnosed as an “eosinophilic substance” 11 , 12 , 13 . The material was reported to be Congo red negative, pale blue with Masson’s trichrome and dark magenta with PAS.…”

“…After the presentation, there was discussion about whether or not to rename this lesion as “nasal septum hyalinosis,” since it has already been reported in the literature three times as “eosinophilic substance” by Doi et al 11 , 12 , 13 A revote resulted in nasal septum hyalinosis (48%), eosinophilic substance (46%), nasal gland proteinosis (3%), interstitial hyalinosis (2%), nasal gland secretion (2%), amyloid (0%) and others (0%). These voting results indicate that all audience members agreed that this lesion was not amyloid, although this is the diagnosis in the current INHAND document 14 .…”

Proceedings of the 2010 National Toxicology Program Satellite Symposium

“…This lesion has been previously diagnosed as “eosinophilic substance” (ES) (Doi et al 2007, 2009, 2010). Present within the mouse nasal septum, it increases in volume with age (which plateaus over time), is more intense in males, and is not associated with degeneration or inflammation.…”

New Findings Concerning Eosinophilic Substance Deposition in Mouse Nasal Septum

“…ES deposited at the interstitium of the clear HE-stained nasal glands only. Additionally, electron microscopic findings suggested that the amorphous material, which is a major component of ES, was produced by the clear HE-stained nasal gland epithelial cells and migrated to the interstitium through the partial opening of the basement membrane (Doi et al 2007(Doi et al , 2009. The amorphous material is probably produced physiologically, because ES was found in all mice (Doi et al 2007;Engelhardt, Gries, and Long 1993;Leininger, Herbert, and Morgan 1996), and neither nasal gland degeneration nor inflammation occurred even when the grade of ES deposition was enhanced (Doi et al 2007), but the significance of ES is not clear.…”