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Changes to the uterine epithelium during the reproductive cycle of two viviparous lizard species ( N iveoscincus spp.)
Author(s) -
Wu Qiong,
Fong Cameron K.,
Thompson Michael B.,
Murphy Christopher R.
Publication year - 2015
Publication title -
acta zoologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.414
H-Index - 37
eISSN - 1463-6395
pISSN - 0001-7272
DOI - 10.1111/azo.12096
Subject(s) - biology , chorioallantoic membrane , vitellogenesis , ultrastructure , uterus , lizard , glycocalyx , epithelium , anatomy , microbiology and biotechnology , embryo , andrology , zoology , endocrinology , oocyte , genetics , medicine
We investigated morphological differences in uterine epithelia of the reproductive cycle between two closely related viviparous skinks, N iveoscincus metallicus (lecithotrophic) and N iveoscincus ocellatu s (placentotrophic), which have similar placental complexity but different degrees of placentotrophy. Scanning ( SEM ) and transmission electron microscopy ( TEM ) revealed that the uterine surface of non‐reproductive females of both species is mainly covered by ciliated cells. As vitellogenesis begins, the uterine epithelium consists of ciliated and non‐ciliated cells under a thin glycocalyx. Microvilli are greatly reduced at mid‐pregnancy, and the uterus differentiates into two structurally distinct regions: the chorioallantoic and the omphaloplacenta. At late stages of pregnancy, the uterine epithelium of chorioallantoic placenta in both species is further ridged, forming a knobbly uterine surface. The ultrastructural evidence between N . metallicus and N . ocellatus cannot strictly account for the distinct differences in their placentotrophy; as yet unexplored molecular nutrient transport mechanisms that are not reflected in uterine ultrastructure must play significant roles in nutrient transportation. Characteristics consistent with a plasma membrane transformation were confirmed in both species.