Effects of Cigarette Smoke on the Nasal Respiratory and Olfactory Mucosa in Allergic Rhinitis Mice

Abstract

Objective: Cigarette smoke (CS) exposure reportedly enhances allergic airway inflammation. However, some studies have shown an association between current cigarette smoke exposure and a low risk for allergic rhinitis. Thus, the impact of CS exposure on allergic rhinitis remains poorly understood. The purpose of this study was to investigate the effects of CS on the respiratory mucosa (RM) and the olfactory epithelium (OE) of mice with allergic rhinitis, as the effects may differ depending on the nasal histological compartments.Methods: Eight-week-old male BALB/c mice were used for this study. We developed a mouse model of smoking by intranasally administering 10 doses of a CS solution (CSS), and a mouse model of allergic rhinitis by sensitization with intraperitoneal ovalbumin (OVA) injection and intranasal challenge with OVA. We examined the effects of CS on the nasal RM and OE in mice with or without allergic rhinitis using histological, serum, and genetic analyses. First, we examine whether CSS exposure induces allergic responses and then, examined allergic responses in the OVA-sensitized allergic rhinitis mice with or without CSS exposure.Results: Short-term CSS administration intensified allergic responses including increased infiltration of eosinophils and inflammatory cells and upregulation of interleukin-5 expression in the nasal RM of OVA-immunized mice, although only CSS induced neither allergic responses nor impairment of the RM and OE. Notably, repetitive OVA-immunization partially impaired the OE in the upper-lateral area, but CSS administration did not reinforce this impairment in OVA-induced allergic mice.Conclusion: Short-term CSS exposure strengthened allergic responses in the nasal RM and did not change the structure of the OE. These results suggest that patients with allergic rhinitis could experience exacerbation of allergic symptoms after CS exposure.

Oral SARS-CoV-2 Inoculation Causes Nasal Viral Infection Leading to Olfactory Bulb Infection: an Experimental Study

“…Regarding the localization of SARS-CoV-2 infection sites in the nasal cavity and differences in the OE damage depending on the site, a previous report showed that it is more likely for SARS-CoV-2 to be found in the lateral region where there is a greater degree of tissue damage 20 , which is consistent with the present results. In addition, this is also analogous to the fact that the OE in the dorsolateral region is susceptible to damage via allergic in ammation 37 . Conversely, it has been reported that the NQO1positive OE is more likely to be damaged by long-term exercise and caloric restriction 38 .…”

Oral SARS-CoV-2 Inoculation Causes Nasal Viral Infection Leading to Olfactory Bulb Infection: An Experimental Study

“…Regarding the localization of SARS-CoV-2 infection sites in the nasal cavity and differences in the OE damage depending on the site, a previous report showed that it is more likely for SARS-CoV-2 to be found in the lateral region where there is a greater degree of tissue damage ( Urata et al., 2021 ), which is consistent with the present results. In addition, this is also analogous to the fact that the OE in the dorsolateral region is susceptible to damage via allergic inflammation ( Ueha et al., 2020 ). Conversely, it has been reported that the NQO1-positive OE is more likely to be damaged by long-term exercise and caloric restriction ( Tuerdi et al., 2018 ).…”

Understanding olfactory dysfunction in COVID-19: Expression of ACE2, TMPRSS2 and Furin in the nose and olfactory bulb in human and mice

“…Animal tissue samples were all obtained from the mice examined in the previous published studies (23,28), because purchasing new animals had been prohibited in our facility due to the epidemic spread. The samples from 6 eight-week-old male C57BL/6 mice (23) and 12 an eight-week-old-male Sprague Dawley rat (28) were used, and the following paraffin-13 embedded tissues were collected; the RM area and OM area of the nose, the OB area, and the 14 kidney and prostate for positive controls of immunostaining (Figure 1A).…”

“…The RM consists of various types of epithelial cells, including ciliated columnar and goblet cells. The OM serves olfaction and consists of the olfactory epithelium (OE) and subepithelial tissues (23). The degree of olfaction is closely related to the number of mature olfactory receptor neurons (ORNs) in the OE.…”