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Cytokines in the oviparity/viviparity transition: evidence of the interleukin‐1 system in a species with reproductive bimodality, the lizard Lacerta vivipara
Author(s) -
Paulesu Luana,
Bigliardi Elisa,
Paccagnini Eugenio,
Ietta Francesca,
Cateni Chiara,
Guillaume Claude Pierre,
Heulin Benoit
Publication year - 2005
Publication title -
evolution and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.651
H-Index - 78
eISSN - 1525-142X
pISSN - 1520-541X
DOI - 10.1111/j.1525-142x.2005.05034.x
Subject(s) - oviparity , biology , lizard , oviduct , embryo , hatchling , zoology , placenta , vertebrate , andrology , fetus , microbiology and biotechnology , pregnancy , ecology , endocrinology , genetics , medicine , gene , hatching
Summary Placental viviparity is a reproductive strategy usually attributed to mammals. However, it is also present in other vertebrate species, e.g. in Squamate reptiles. Although the immunological mechanisms that allow the survival of the semi‐allogenic embryo in maternal tissues are still largely unknown, cytokines seem to play an important role in mammalian reproduction. Previous studies in our laboratory showed that interleukin‐1 (IL‐1), a cytokine associated with implantation in mice, is also expressed at the materno‐fetal interface of placental viviparous Squamates. In this study, we used the model of Lacerta vivipara , which exhibits reproductive bimodality, that is, the coexistence of oviparous and viviparous populations. By means of immunohistochemistry and anti‐human antibodies, we showed that uterine tissues of L. vivipara (seven oviparous and six viviparous animals) expressed the two IL‐1 isoforms, IL‐1α and IL‐1β, and the type I IL‐1 receptor (IL‐1R tI) both at the pre‐ovulatory stage and during gestation, with no significant difference between oviparous and viviparous females. In L. vivipara , as in most oviparous Squamates, an important phase of embryonic development takes place in the mother's oviduct, before egg‐laying. Moreover, although thinner than in oviparous females, an eggshell membrane persists throughout gestation in viviparous females also, which develop a very simple type of placenta. The data suggest that immunological mechanisms that allow the survival of the semi‐allogenic embryo in maternal tissues are independent of the timing or intimacy of contact between maternal and fetal tissues.