Untitled

Abstract

Background: The paca is a South American rodent with potential as a commercial food animal. We examined paca placenta as part of a wider effort to understand the reproductive biology of this species.

Subplacental development in Galea spixii

“…Our findings in the prea were in accordance to former studies that the subplacenta was active and proliferative in early and mid-gestation (Davies et al 1961a, 1961b, Kaufmann & Davidoff 1977, Wolfer & Kaufmann 1980, Kaufmann 2004, Miglino et al 2002, 2004, Bonatelli et al 2005, Oliveira et al 2006, Rodrigues et al 2006, Bosco et al 2007, Mess 2003, 2007a, 2007b, Mess & Carter 2007, 2012a, 2012b, Kanashiro et al 2009, Flamini et al 2011. Immunostaining for the proliferation marker PCNA and revealing the mitotic index by morphology both resulted in high proliferation early on, followed by an abrupt decrease around day 45 and further decrease towards term.…”

“…For the first time, proliferation processes inside the subplacenta were revealed by three independent methods, supporting the former results. During advanced gestation, the subplacenta generally degenerated (Davies et al 1961a, 1961b, Kaufmann & Davidoff 1977, Wolfer & Kaufmann 1980, Miglino et al 2002, 2004, Mess 2003, 2007a, 2007b, Kaufmann 2004, Bonatelli et al 2005, Oliveira et al 2006, 2012a, 2012b, Rodrigues et al 2006, Bosco et al 2007, Mess & Carter 2007, Kanashiro et al 2009, Flamini et al 2011. In addition, these results corroborate with those described in the capybara (Kanashiro et al 2009) and in the punaré (Oliveira et al 2012a), however the final phases are not approached in this regard.…”

“…The subplacenta historically was regarded as an organ without fetomaternal exchange, mainly based on studies of the guinea pig where the maternal blood system was stopped by coagulation from day 20 on and fully disappeared at least at day 27, in contrast to the fetal system that started around day 26 to 32 (Kaufmann & Davidoff 1977, Wolfer & Kaufmann 1980, Kaufmann 2004. However, recent studies showed a short-term overlap in the prea, the degu Octodon degus, the punare Thrichomys aperoides, the capybara Hydrochaeris hydrochaeris as well as paca Cunniculus paca and agouti Dasyprocta leporina (Miglino et al 2002, 2004, Bonatelli et al 2005, Bosco et al 2007, Mess 2007a, 2012a. Here, we argued for an even more intimate overlap, On the contrary, a hemotricorial barrier is observed in Sigmodontinae (Favaron et al 2011).…”

“…In the last decade placentation was investigated in several caviomorph species (Davies et al 1961a, 1961b, Kaufmann & Davidoff 1977, Wolfer & Kaufmann 1980, Miglino et al 2002, 2004, Kaufmann 2004, Bonatelli et al 2005, Oliveira et al 2006, Rodrigues et al 2006, Bosco et al 2007, Mess 2003, 2007a, 2007b, Mess & Carter 2007, Kanashiro et al 2009, Flamini et al 2011, Oliveira et al 2012a, 2012b) revealing a quite stable pattern of evolution that is largely independent from size diameters or reproductive specializations (Kanashiro et al 2009, Flamini et al 2011, Mess 2011, 2014. In particular, trophoblast invasion in caviomorphs is associated with a specialized area within the placental disk, the so-called subplacenta (Kaufmann 2004, Rodrigues et al 2006, Mess 2007a, 2014.…”

Placental Evolution within the Supraordinal Clades of Eutheria with the Perspective of Alternative Animal Models for Human Placentation

“…Thus, several taxa including rare or wildlife species have been studied by means of histology and modern methods like immunohistochemistry or proper fine structural investigations by electron microscopy. Among 2 Advances in Biology them are nonmurine rodents native to South America and Africa [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40], as was shown by Figure 2, bats [41][42][43], anteaters and armadillos [44,45], and some other taxa [46][47][48][49][50][51]. Also, there were several promising attempts to reinvestigate historical histological material from museum collections such as neotropical primates [52] or great apes [53][54][55][56] in order to answer open questions.…”