PUBLICATION

Histopathological analysis of the olfactory epithelium of zebrafish (Danio rerio) exposed to sublethal doses of urea

Authors

Bettini, S., Lazzari, M., Ferrando, S., Gallus, L., Franceschini, V.

ID

ZDB-PUB-151030-10

Date

2016

Source

Journal of anatomy 228(1): 59-69 (Journal)

Registered Authors

Keywords

PCNA, Gα olf, TRPC2, TrkA, neuroepithelium

MeSH Terms

GTP-Binding Protein alpha Subunits/metabolism
Urea/toxicity*
Olfactory Bulb/drug effects
Olfactory Receptor Neurons/drug effects
Immunohistochemistry
Zebrafish/physiology*
Analysis of Variance
Water Pollutants/toxicity*
Olfactory Mucosa/drug effects*
Animals

(all 10)

PubMed

26510631 Full text @ J. Anat.

Abstract

Chronic renal disease is known to alter olfactory function, but the specific changes induced in olfactory organs during this process remain unclear. Of the uraemic toxins generated during renal disease, high levels of urea are known to induce hyposmic conditions. In this study, the effects of environmental exposure to elevated concentrations of urea (7, 13.5 and 20 g L(-1) ) on the sensory mucosa of zebrafish in acute toxicity and chronic toxicity tests were described. It was observed that lamellae maintained structural integrity and epithelial thickness was slightly reduced, but only following exposure to the highest concentrations of urea. Pan-neuronal labelling with anti-Hu revealed a negative correlation with levels of urea, leading to investigation of whether distinct neuronal subtypes were equally sensitive. Using densitometric analysis of immunolabelled tissues, numbers of Gα olf -, TRPC2- and TrkA-expressing cells were compared, representing ciliated, microvillous and crypt neurons, respectively. The three neuronal subpopulations responded differently to increasing levels of urea. In particular, crypt cells were more severely affected than the other cell types, and Gα olf -immunoreactivity was found to increase when fish were exposed to low doses of urea. It can be concluded that exposure to moderate levels of urea leads to sensory toxicity directly affecting olfactory organs, in accordance with the functional olfactometric measurements previously reported in the literature.

Genes / Markers

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