Abstract
The sperm produced in the seminiferous tubules pass through the rete testis, efferent ducts, and epididymis. The epididymis has three distinct regions known as caput, corpus, and cauda. The transit through the epididymis is an essential process in sperm maturation. The lumen of each epididymal region has a unique fluid composition regulated by many ion channels and transporters in the epithelial cells. The objective of this study was to map the sites of localization of ion channels ENaC and CFTR along the length of the mouse and rat epididymis using confocal microscopic imaging. The integrity of the fine structure of the tissues was verified by fluorescent phalloidin staining of actin filaments visualized by high-resolution confocal microscopy. The 2D and 3D images showed preservation of the stereocilia. Based on these images we determined morphometric parameters of the epithelial cells and ducts. ENaC and CFTR immunofluorescence appeared almost continuously on the apical membrane of caput and in smooth muscle myoid cells. In cauda, CFTR expression was observed continuously in long stretches of epithelium interrupted by clusters of cells that showed no CFTR expression. Similar patterns of localization were observed in both mouse and rat samples. Mutations in the CFTR gene are known to result in male infertility. Based on the widespread presence of ENaC along the epididymis we suggest that mutations in ENaC subunits may also be associated with male infertility. The diverse phenotypes associated with CFTR mutations may be due to malfunction of CFTR at specific subcellular locations in the male reproductive system.
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We are grateful to Prof. Aaron Hanukoglu (Tel Aviv University, Sackler School of Medicine) for useful discussions and for his critical evaluation of the manuscript.
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10735_2019_9813_MOESM1_ESM.png
Negative control for the specificity of the anti-CFTR antiserum. The anti-CFTR antisera was reacted first with antigen peptide provided with the antiserum. A mouse caput section was then reacted with this antiserum using the same protocol as normal samples. a DAPI staining; b control immunofluorescence with anti-CFTR antisera pre-incubated with the CFTR antigen; and c merged image. (PNG 1925 KB)
10735_2019_9813_MOESM2_ESM.png
The primary negative control for the specificity of the anti-ENaCα antisera. A rat epididymal section was reacted using the same protocol except primary antisera (anti-ENaCα) was omitted from the reaction. a DAPI staining; b control immunofluorescence only with secondary antisera; and c merged image. (PNG 2147 KB)
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Sharma, S., Hanukoglu, I. Mapping the sites of localization of epithelial sodium channel (ENaC) and CFTR in segments of the mammalian epididymis. J Mol Hist 50, 141–154 (2019). https://doi.org/10.1007/s10735-019-09813-3
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DOI: https://doi.org/10.1007/s10735-019-09813-3