Morphological and histological studies of the adrenal gland in the Japanese quail (Coturnix japonica)

Post-hatching developmental changes in the adrenal gland of the Japanese quail (Coturnix coturnix japonica): Histological, immunohistochemical, and electron microscopic studies

The adrenal glands are paired abdominal endocrine organs vital to the bird's health. The present research aimed to provide a comprehensive examination of the histological, ultrastructural, and immunohistochemical investigations of the adrenal gland in Japanese quail during the post hatching period. The current study was performed on 21 healthy Japanese quail chicks at different post hatching periods. Our results showed the adrenal gland is surrounded by a connective tissue capsule, which consists of dense collagen fibers containing large blood vessels, chromaffin cells, autonomic ganglia, fibroblasts, and migrating Schwann cells. The zonation of the adrenal gland is composed of a subcapsular layer, a peripheral zone, and a central zone, which gets more pronounced with age. At the ultrastructural level, the interrenal cells take the steroid-secreting cells characters; they have varying amounts of lipid droplets and abundant mitochondria. Adrenal medullary chromaffin cells showed positive immunoreactivity to the NSE. With increasing age, the chromaffin tissue's Sox10 immunoreactivity increased. β-catenin is expressed within the plasmalemma and the cytoplasm of the interrenal and chromaffin cells and its reactivity increased with age, especially in the chromaffin cells. Our results indicate the adrenal gland undergoes significant morphological changes during the postnatal life. Overall, the postnatal period is an important time for the development and maturation of the adrenal glands.

Adaptive remodeling of the stimulus-secretion coupling: Lessons from the 'stressed' adrenal medulla

Stress is part of our daily lives and good health in the modern world is offset by unhealthy lifestyle factors, including the deleterious consequences of stress and associated pathologies. Repeated and/or prolonged stress may disrupt the body homeostasis and thus threatens our lives. Adaptive processes that allow the organism to adapt to new environmental conditions and maintain its homeostasis are therefore crucial. The adrenal glands are major endocrine/neuroendocrine organs involved in the adaptive response of the body facing stressful situations. Upon stress episodes and in response to activation of the sympathetic nervous system, the first adrenal cells to be activated are the neuroendocrine chromaffin cells located in the medullary tissue of the adrenal gland. By releasing catecholamines (mainly epinephrine and to a lesser extent norepinephrine), adrenal chromaffin cells actively contribute to the development of adaptive mechanisms, in particular targeting the cardiovascular system and leading to appropriate adjustments of blood pressure and heart rate, as well as energy metabolism. Specifically, this chapter covers the current knowledge as to how the adrenal medullary tissue remodels in response to stress episodes, with special attention paid to chromaffin cell stimulus-secretion coupling. Adrenal stimulus-secretion coupling encompasses various elements taking place at both the molecular/cellular and tissular levels. Here, I focus on stress-driven changes in catecholamine biosynthesis, chromaffin cell excitability, synaptic neurotransmission and gap junctional communication. These signaling pathways undergo a collective and finely-tuned remodeling, contributing to appropriate catecholamine secretion and maintenance of body homeostasis in response to stress.

Role of Uterine Telocytes During Pregnancy

Endometrial remolding and angiogenesis are critical events that occur during pregnancy in order to establish uteroplacental vascular communication. This study investigated the role of uterine telocytes (TCs) in pregnancy. We analyzed the distribution of TCs and morphological changes in the endometrium of the gravid rabbit uterus at different stages of pregnancy: after ovulation, pre-implantation (day 7), post-implantation (days 8 and 9), and mid-pregnancy (day 14) and late (days 21–28) pregnancy. TCs gradually increased with the progression of pregnancy. They had distinctive telopodes (TPs) and podoms, with intranucleolar chromatin. The TCs established contact with decidual cells, growing a glandular epithelium, blood vessels, and immune cells, such as lymphocytes, neutrophils, and macrophages. The TCs underwent morphological changes at the post-implantation phase. They acquired thick and voluminous TPs, formed an extensive three-dimensional (3D) labyrinth at mid-pregnancy, and exhibited irregular-shaped nuclei and a dilated rough endoplasmic reticulum at late pregnancy. They also acquired a convoluted contour-formed complex network. Scanning electron microscopy (SEM) showed an extensive 3D network in the endometrium, forming a condensed sheath at late pregnancy. Transmission electron microscopy and SEM detected fenestrated TPs, and TCs were identified by CD34 and vascular endothelial growth factor expression. TCs also expressed matrix metalloproteinase-9 and transforming growth factor beta-1. Results suggested that TCs might play an essential role in maternal placenta formation, especially decidualization, regulation of uterine gland development, and neovascularization of maternal uterine blood vessels.

Lactoferrin improves the immune response and resistance of silver carp, a hematological, light (histochemical and immunohistochemical), fluorescent, and scanning electron microscopic study

Lactoferrin is a multifunctional protein that has roles in iron metabolism, cell generation and differentiation, and antibacterial, antiviral, and antiparasitic activity. The study aim was to evaluate the effect of dietary lactoferrin powder on the innate immune response and disease resistance of silver carp (Hypophthalmichthys molitrix) infected with Vibrio vulnificus. The study also investigates immune cells in different organs including gills, intestine, spleen, liver, and pancreas using light, scan electron microcopy. Two diet regimes, a basic diet and a 600-mg/kg bovine lactoferrin-supplemented diet were used. The fish were fed for 30 successive days. We included 270 apparently healthy silver carp (H. Molitrix) with an average body weight of 10 ± 2 g/fish. Addition of lactoferrin to the diet led to an increase in the activity of non-specific immune parameters; lymphocytes, and in the monocytes percentage, and in total protein, serum globulin, and albumin, with a corresponding increase in phagocytic activities and indices. The histological analysis revealed increase immune cells such as lymphocytes in intestine, rodlet cells in liver, gills, and pancreas, and the macrophages in liver, pancreas as well as spleen. The lactoferrin-supplemented diet significantly increased survival and disease resistance following V. vulnificus challenge, which seemed to correspond to an enhancement of non-specific immune functions in H. molitrix. RESEARCH HIGHLIGHTS: The study evaluates the effect of dietary lactoferrin powder on the innate immune response and disease resistance of silver carp (Hypophthalmichthys molitrix) infected with Vibrio vulnificus. The study also investigates immune cells in different organs including gills, intestine, spleen, liver, and pancreas using light, scan electron microcopy. Lactoferrin increases the activity of nonspecific immune parameters; lymphocytes, and in the monocytes percentage, and in total protein, serum globulin, and albumin, with a corresponding increase in phagocytic activities and indices. The histological analysis revealed increase immune cells such as lymphocytes in intestine, rodlet cells in liver, gills, and pancreas, and the macrophages in liver, pancreas as well as spleen.