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Immunolocalization of the Cholesterol Transporters ABCA 1 and ABCG 1 in Canine Reproductive Tract Tissues and Spermatozoa
Author(s) -
Palme N,
Becher AC,
Merkl M,
Glösmann M,
Aurich C,
SchäferSomi S
Publication year - 2014
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/rda.12294
Subject(s) - capacitation , acrosome , biology , acrosome reaction , epididymis , sperm , andrology , atp binding cassette transporter , endocrinology , transporter , biochemistry , medicine , genetics , gene
Contents The mammalian sperm membrane undergoes cholesterol efflux during maturation and fertilization. Although ATP ‐binding cassette ( ABC ) transporters are known to transport cholesterol through cell membranes in other organs, their presence in canine testis, epididymis and sperm has not been proven to date. Hence, the aim of the present study was to localize the ABC transporters ABCA 1 and ABCG 1 in canine testicular and epididymidal tissue as well as in spermatozoa membranes. To this end, semen samples from 12 dogs as well as testicles and epididymides of four young and healthy dogs were prepared for immunohistochemistry, respectively. Capacitation and acrosome reaction ( AR ) were induced in aliquots of the semen samples before immunostaining to assess changes in the expression of ABCA 1 and ABCG 1. Evaluation by confocal microscopy revealed the presence of both ABCA 1 and ABCG 1 in canine testicles and of ABCA 1 in the epididymides. In spermatozoa, only ABCA 1 immunoreactivity was detected, mainly in the region of the acrosome and midpiece. After induction of capacitation, ABCA 1 signal persisted in the acrosome but disappeared after AR , indicating a loss of ABCA 1 with the loss of the acrosome. We conclude that ABCA 1 and ABCG 1 are expressed in canine testis, whereas only ABCA 1 is expressed in epididymis and spermatozoa membrane, both transporters probably contributing to the regulation of membrane cholesterol content.