[Immunoblot and immunohistochemical analysis of CYP2A expression in human olfactory mucosa]

Abstract

Objective: To investigate the nasal expression of CYP2A proteins in human.

Methods: Immunoblot analysis was used to detect fetal tissues at 96-185 days of gestational age and in surgical biopsy tissues from different regions of nasal cavity of 36 adult patients, and immunohistochemical methods were used to localize CYP2A proteins' cellular distribution.

Results: In adults, CYP2A protein was detected in olfactory microsomes from 8 of 10 individual, but not in the respiratory nasal microsomes from 37 individual. Quantitative immunoblot analysis confirmed that CYP2A proteins were selectively expressed in the olfactory region in both adult and fetal tissues. Interestingly, the levels of CYP2A proteins in nasal microsomes were generally higher in fetuses than in adults. The CYP2A protein content in olfactory microsomes ranged from 0.1 to 1.1 pmol/mg among adult nasal microsomes, while among five fetuses ranged from 0.8 to 5.3 pmol/mg microsomal protein, with a trend of developmental increase in expression level. Immunohistochemical studies confirmed that the CYP2A proteins were expressed in the supporting cells in the olfactory epithelium and in the Bowman's glands in the lamina propria.

Conclusions: CYP2A proteins expression in human olfactory mucosa indicates that olfactory mucosa is metabolic target site of the xenobiotics. Also CYP2A has a relationship with olfaction. The prenatal expression of the CYP2A proteins in the OM suggests potential risks of developmental toxicity from maternally derived xenobiotics.