Lamina Propria Of Nasal Mucosa Research Articles

Identification and Analysis of Natural Killer Cells in Murine Nasal Passages.

BackgroundNatural killer (NK) cells in the upper respiratory airways are not well characterized. In the current study, we sought to characterize and functionally assess murine nasal NK cells.MethodsUsing immunohistochemistry and flow cytometry, we compared the nasal NK cells of Ncr1 GFP/+ knock-in mice, whose NK cells produced green fluorescent protein, with their splenic and pulmonary counterparts. In addition, we functionally analyzed the nasal NK cells of these mice in vitro. To assess the in vivo functions of nasal NK cells, C57BL/6 mice depleted of NK cells after treatment with PK136 antibody were nasally infected with influenza virus PR8.ResultsImmunohistochemical analysis confirmed the presence of NK cells in the lamina propria of nasal mucosa, and flow cytometry showed that these cells were of NK cell lineage. The expression patterns of Ly49 receptor, CD11b/CD27, CD62L and CD69 revealed that nasal NK cells had an immature and activated phenotype compared with that of their splenic and pulmonary counterparts. Effector functions including degranulation and IFN(interferon)-γ production after in vitro stimulation with phorbol 12-myristate-13-acetate plus ionomycin or IL(interleukin)-12 plus IL-18 were dampened in nasal NK cells, and the depletion of NK cells led to an increased influenza virus titer in nasal passages.ConclusionsThe NK cells of the murine nasal passage belong to the conventional NK cell linage and characteristically demonstrate an immature and activated phenotype. Despite their hyporesponsiveness in vitro, nasal NK cells play important roles in the host defense against nasal influenza virus infection.

Regeneration of free grafted respiratory epithelium on severely altered lamina propria.

The lamina propria of nasal mucosa has been thought to play a key role in function and metabolism of respiratory epithelia by allowing exchange of various substances and migratory cells from blood vessels into the epithelium. Here we show that the lamina propria of mucosa transplanted to rat rectus abdominis muscle looses its typical structure and becomes vascularized connective tissue. In the subepithelial space of free grafted respiratory epithelia nasal glands, ducts and nerves degenerate and are no more detectable 3 weeks after transplantation. By contrast the epithelial cell layer regenerates, resulting in a healthy appearing mucosa. Histological and functional controls revealed that regenerated respiratory epithelium lies on a layer of vascularized connective tissue and displays normal cellular differentiation and ciliary function. The present experiments demonstrate that the lamina propria can be replaced by vascularized connective tissue without functional loss of the overlaying epithelium. Thus the results argue against a key role of lamina propria in mucosal function.

Characteristics of capillary permeability in nasal mucosa.

The transendothelial passage of horseradish peroxidase (HRP) and colloidal carbon and diffusion of HRP in pericapillary space, injected intravenously into rats, was studied at the light microscopic and ultrastructural level in the nasal mucosa. In the lamina propria of the mucosa in the middle third of the nasal septum of rats, the capillaries directly beneath the epithelium were mostly with fenestrae, while the capillaries around the nasal gland were without the fenestrae. The permeability of the capillaries in the lamina propria of the nasal mucosa was very high and some of the endothelial cells were wide open, like liver sinusoid, allowing free passage of carbon pasrticles. Marked transendothelial passage was also noted at ten seconds after HRP infusion through the capillaries without fenestrae located around the nasal gland. On the other hand, no extracapillary leakage of HRP was noted even at 150 seconds after its infusion in the capillaries without fenestrae located in the muscles. The permeability of small venules located in the lamina propria of nasal mucosa also was extremely high. The reasons for the greater permeation of HRP through capillaries of nasal mucosa are as follows. First, the endothelial cell junction was loose in the nasal mucosa and in some capillaries endothelium had holes like liver sinusoid. Second, interstitium surrounding the capillary was loose in nasal mucosa.