Javier Masot

Structure of the ovine pineal gland during prenatal development

Regodón S, Franco A, Masot J, Redondo E. Structure of the ovine pineal gland during prenatal development. J. Pineal Res. 1998; 25:229–239.

Histomorphometric and immunohistochemical study of the goat rumen during prenatal development.

This study sought to chart the ontogenesis of the goat rumen by histomorphometric examination, scanning electron microscopy and immunohistochemical analysis. A total of 140 goat embryos and fetuses were used, from the first stage of prenatal life until birth. The appearance of the rumen from the primitive gastric tube was observed at 35 days of prenatal life (CRL 3 cm, 23% gestation). By 38 days (CRL 4.3 cm CRL, 25% gestation) the ruminal wall comprised three layers: an internal epithelial layer, a middle layer of pluripotential blastemic tissue and an external layer or serosa. Ruminal pillars were visible at 46 days (CRL 6 cm, 30% gestation), and by 76 days (CRL 18 cm, 50% gestation) ruminal papillae were starting to appear. Under scanning electron microscopy, by 50 days (CRL 7.7 cm, 33% gestation) small ruminal papillae were observed protruding from the surface. Finally, neuroendocrine cells (synaptophysin, SYP) were detected at 53 days (CRL 9 cm CRL, 35% gestation), while glial cell markers (glial fibrillary acidic protein—GFAP, and vimentin‐VIM) were found at 108 days (CRL 31 cm, 72% gestation) and 39 days (CRL 4.4 cm, 26% gestation), respectively. Neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) were detected immunohistochemically at 113 days (CRL 33 cm, 75% gestation) and 120 days (CRL 35 cm, 80% gestation), respectively. In conclusion, histomorphogenesis of the rumen in goats was similar to that reported in deer, but rather slower than observed for sheep or cattle. Anat Rec, 2012.

Ontogenesis of the rumen: A comparative analysis of the Merino sheep and Iberian red deer

The aim of this study is to describe differences in the ontogenesis of the rumen in the sheep (domestic ruminant) and deer (wild ruminant). A total of 50 embryos and fetuses of Merino sheep and 50 of Iberian deer were used, from the first stages of prenatal life until birth. For the study, the animals were divided into five experimental groups according to the most relevant histological characteristics. The appearance of the rumen from the primitive gastric tube was earlier in the sheep (22% gestation, 33 days) than in the deer (25% gestation, 66 days). In both cases it displayed a primitive epithelium of a stratified, cylindrical, non-ciliary type. At around 28% gestation in the sheep (42 days) and 26% (67 days) in the deer, the rumen was configured of three clearly-differentiated layers: internal or mucosal, middle or muscular and external or serosal. In both species the stratification of the epithelial layer was accompanied by modifications in its structure with the appearance of the ruminal pillars and papillae. The pillars appeared before the papillae and the appearance of both structures was always earlier in the deer (pillars: 70 days, 27% gestation; papillae: 97 days, 36% gestation) than in the sheep (pillars: 42 days, 28% gestation; papillae: 57 days, 38% gestation). The outlines of the ruminal papillae appeared as evaginations of the basal zone toward the ruminal lumen, dragging in their formation the basal membrane, the lamina propria and the submucosa. The tegumentary mucosa of the rumen was without secretion capability in the first embryonic phases. From 67 days (26% gestation) the neutral mucopolysaccharides appeared in the deer and at 46 days (30% gestation) in the sheep. In both cases they continued to decrease until birth, this diminution being more pronounced in the deer. Finally, the presence of neuroendocrine and glial cells was detected in the deer at earlier stages than in the sheep.

Histomorphometric and immunohistochemical study of the goat reticulum during prenatal development.

This study sought to describe the morphological changes taking place in the goat reticulum during prenatal development, using histomorphometric and immunohistochemical techniques. A total of 140 goat embryos and foetuses were used, from the first stages of prenatal life until birth. Differentiation of the reticulum as a separate compartment of the primitive gastric tube was observed at 35 days of prenatal life (23% gestation). By 38 days (25% gestation) the reticular wall comprised three layers: an internal epithelial layer, a middle layer of pluripotential blastemic tissue and an external layer or serosa. Primary reticular crests were visible at 59 days (38% gestation) as evaginations of the epithelial stratum basale, marking the earliest histological differentiation of future reticular cells. Secondary reticular crests were observed at 87 days (61% gestation). Corneum papillae first became apparent on the lateral surface of primary reticular crests at 101 days (64% gestation). The muscularis mucosae was visible by 101 days (64% gestation) in primary reticular crests. Neuroendocrine cells were detected by synaptophysin at 64 days (43% gestation), while glial cell markers (glial fibrillary acidic protein and vimentin) were observed at 64 days (43% gestation) and 38 days (25% gestation), respectively. The peptidergic innervation markers such as neuropeptide Y and vasoactive intestinal polypeptide were detected at 75 days (50% gestation). In conclusion, prenatal development of the reticulum - like that of the rumen - appears to take place somewhat earlier in goats than in sheep or cattle, but at a similar rate to that reported in deer.

Ontogenesis of the Reticulum with Special Reference to Neuroendocrine and Glial Cells: A Comparative Analysis of the Merino Sheep and Iberian Red Deer

The present study was designed to compare the differences in the ontogenesis of the reticulum in sheep (domestic ruminant) and deer (wild ruminant). A total of 50 embryos and foetuses Merino sheep and 50 Iberian deer were used, from the first pre‐natal life until birth. The appearance of the reticulum from the primitive gastric tube was earlier in the sheep (22% gestation, 33 days) than in the deer (25% gestation, 66 days). In both cases, it displayed a primitive epithelium of a stratified, cylindrical, non‐ciliary type. At around 48% gestation in the sheep (72 days) and 36% (97 days) in the deer, the reticulum was configured of four clearly differentiated layers: mucosa (with epithelial layer and lamina propria), submucosa, tunica muscularis and serosa. The stratification of the epithelial layer was accompanied by modifications in its structure with the appearance of the primitive reticular ribs. The primary ribs began to be formed first in the deer, at 117 days of pre‐natal life (40% gestation) and later in the sheep (79 days, 53% gestation). The differentiation of the corneum papillae in the primary ribs coincided with the appearance of secondary reticular ribs. These structures began to be formed first in the deer, at 142 days of pre‐natal life (51% gestation) and later in the sheep (83 days, 55% gestation). The presence of neuroendocrine cells (non‐neuronal enolase‐positive cells) in the reticular mucosa was not detected until 97 days (36% gestation) in deer and 81 days (54% gestation) in sheep. The presence of glial cells (GFAP‐positive cells) occurred at around 142 days (51% gestation) in deer and at 112 days (75% gestation) in sheep. In conclusion, the presence of neuroendocrine and glial cells was detected in deer at earlier stages than sheep.

Immunohistochemical evaluation of the goat forestomach during prenatal development

Here we report the detection and distribution of synaptophysin (SPY), non-neuronal enolase (NNE), glial fibrillary acidic protein (GFAP), vimentin (VIM), neuropeptide Y (NPY), and vasoactive intestinal peptide (VIP) expression in the goat forestomach during prenatal development. A total of 140 embryos and fetuses were examined to evaluate protein expression from the first stage of prenatal life until birth. In all cases, SPY immunoreactivity was detected at 53 days gestation in the lamina propria-submucosa, tunica muscularis, serosa, and myenteric plexuses. Immunoreactivity to NNE was observed at 64 days gestation in the same locations as well as the epithelial layer. Glial cells were found at 64 days as indicated by signals corresponding to GFAP and VIM at 39 days. Positive staining for NPY and VIP was observed at 113, 75, and 95 days in the rumen, reticulum, and omasum, respectively, in the lamina propria-submucosa, tunica muscularis, and myenteric plexuses of each of these gastric compartments. These findings indicate possible preparation of the fetal goat forestomach for postnatal function. Compared to other ruminant species, neuroendocrine cells, glial cells and peptidergic innervations markers were detected earlier compared to sheep but at around the same stage as in deer.

Histomorphometric study of the goat stomach during prenatal development.

The aim of this study was to perform a morphometric analysis of the different structural tissue layers of the goat stomach to study their prenatal growth from mathematical models fitted to these morphometric data. A total of 90 embryos and fetuses were used, from the early stages of prenatal life until birth. The growth rate of the gastric wall was slower than that of body length; rumen was the stomach compartment displaying slowest growth. In the three non-glandular compartments, the epithelial layer grew faster than the gastric wall itself, while the growth rate of the abomasal epithelium declined in the early stages of development. A decline in growth rate was also observed for the lamina propria and submucosa in rumen and reticulum from the early embryonic stages, whereas in omasum and abomasum these layers continued to grow as gestation progressed. The tunica muscularis displayed consistent growth in all compartments, growing faster than the gastric wall. Serosa thickness increased as gestation progressed, displaying a decline in growth-rate only in the omasum. In conclusion, the dynamics of gastric wall growth were governed by the growth rate of each of the component tissue layers.