Different Stages Of Postnatal Development Research Articles

Changes in the expression of satellite glial cell-specific markers during postnatal development of rat sympathetic ganglia

The sympathetic ganglia represent a final motor pathway that mediates homeostatic “fight and flight” responses in the visceral organs. Satellite glial cells (SGCs) form a thin envelope close to the neuronal cell body and synapses in the sympathetic ganglia. This unique morphological feature suggests that neurons and SGCs form functional units for regulation of sympathetic output. In the present study, we addressed whether SGC-specific markers undergo age-dependent changes in the postnatal development of rat sympathetic ganglia. We found that fatty acid-binding protein 7 (FABP7) is an early SGC marker, whereas the S100B calcium-binding protein, inwardly rectifying potassium channel, Kir4.1 and small conductance calcium-activated potassium channel, SK3 are late SGC markers in the postnatal development of sympathetic ganglia. Unlike in sensory ganglia, FABP7 + SGC was barely detectable in adult sympathetic ganglia. The expression of connexin 43, a gap junction channel gradually increased with age, although it was detected in both SGCs and neurons in sympathetic ganglia. Glutamine synthetase was expressed in sensory, but not sympathetic SGCs. Unexpectedly, the sympathetic SGCs expressed a water-selective channel, aquaporin 1 instead of aquaporin 4, a pan-glial marker. However, aquaporin 1 was not detected in the SGCs encircling large neurons. Nerve injury and inflammation induced the upregulation of glial fibrillary acidic protein, suggesting that this protein is a hall marker of glial activation in the sympathetic ganglia. In conclusion, our findings provide basic information on the in vivo profiles of specific markers for identifying sympathetic SGCs at different stages of postnatal development in both healthy and diseased states.

Phenotypic characterization of liver tissue heterogeneity through a next-generation 3D single-cell atlas

Three-dimensional (3D) geometrical models are potent tools for quantifying complex tissue features and exploring structure–function relationships. However, these models are generally incomplete due to experimental limitations in acquiring multiple (> 4) fluorescent channels in thick tissue sections simultaneously. Indeed, predictive geometrical and functional models of the liver have been restricted to few tissue and cellular components, excluding important cellular populations such as hepatic stellate cells (HSCs) and Kupffer cells (KCs). Here, we combined deep-tissue immunostaining, multiphoton microscopy, deep-learning techniques, and 3D image processing to computationally expand the number of simultaneously reconstructed tissue structures. We then generated a spatial single-cell atlas of hepatic architecture (Hep3D), including all main tissue and cellular components at different stages of post-natal development in mice. We used Hep3D to quantitatively study 1) hepatic morphodynamics from early post-natal development to adulthood, and 2) the effect on the liver's overall structure when changing the hepatic environment after removing KCs. In addition to a complete description of bile canaliculi and sinusoidal network remodeling, our analysis uncovered unexpected spatiotemporal patterns of non-parenchymal cells and hepatocytes differing in size, number of nuclei, and DNA content. Surprisingly, we found that the specific depletion of KCs results in morphological changes in hepatocytes and HSCs. These findings reveal novel characteristics of liver heterogeneity and have important implications for both the structural organization of liver tissue and its function. Our next-gen 3D single-cell atlas is a powerful tool to understand liver tissue architecture, opening up avenues for in-depth investigations into tissue structure across both normal and pathological conditions.

Ontogeny of adropin and its receptor expression during postnatal development and its pro-gonadal role in the ovary of pre-pubertal mouse

Adropin, a highly conserved multifunctional peptide hormone, has a beneficial effect on the maintenance of gluco-lipid homeostasis, endothelial and cardiovascular functions. However, the expression and potential role of adropin in ovarian function are not fully elucidated. The present study aimed to investigate the expression of adropin and GPR19 in the mice ovary during various stages of postnatal development. This study also explored whether the treatment of adropin can modulate the timing of puberty, for which pre-pubertal mice were treated with adropin. The result showed the intense immunoreactivity of adropin in TICs, while GPR19 immunoreactivity was noted in GCs in infantile, pre-pubertal, and pubertal mice ovary. Also, adropin and GPR19 are highly expressed in the CL of the ovary of reproductively active mice. The fact that adropin expression in the ovary at different stages of postnatal development positively correlated with circulating progesterone and estradiol indicated that it has a role in the production of steroid hormones. Furthermore, the results of in vivo studies in pre-pubertal mice showed that adropin promotes early folliculogenesis by enhancing the proliferation (PCNA) of GCs of cortical ovarian follicles and promotes estradiol production by enhancing the expression of GPR19, StAR, CYP11A1 and aromatase proteins. Also, adropin treatment increases the Bax/Bcl2 ratio and expression of cleaved caspase-3 and ERα proteins, which may result in increased apoptosis of medullary follicles leading to the formation of a well-developed interstitium with interstitial glandular cells. Collectively, these findings indicate that adropin may be a factor that accelerates pubertal development in the ovary and could be utilized as a therapeutic approach for treating pubertal delay.

Dysregulation of GABAergic System in the Inferior Colliculi of Rats during the Development of Audiogenic Epilepsy

Epilepsy is tightly associated with dysfunction of inhibitory GABA neurotransmission. In this study, Krushinsky–Molodkina (KM) rats genetically prone to audiogenic seizures (AGS) were used. KM rats are characterized by the development of audiogenic epilepsy during postnatal ontogenesis, with AGS onset at the age of 1.5–2 months and fully developed AGS expression by 3rd month. We analyzed GABAergic system of the inferior colliculi (IC) of KM rats at different stages of postnatal development. Wistar rats were used as a control. In the IC of young KM rats, Na+/K+/Cl– cotransporter 1 (NKCC1) expression was increased, while K+/Cl– cotransporter 2 (KCC2) was unchanged indicating impairment of postsynaptic GABA action at early stages of postnatal development. Moreover, we revealed also an increase in the expression of vesicular GABA transporter (VGAT) in the IC which additionally pointed on the higher activity of GABA release. In adult rats, in opposite, we revealed a decrease in the expression of KCC2 transporter indicating downregulation of GABA inhibition on the target cells. Thus, GABA dysregulation in the IC can mediate the seizure susceptibility in adult KM rats.

Structural Organization of GABA- and Nitroxidergic Systems of Subfornical Organ in Wistar Rats Postnatal Development

The subfornical organ (SFO) is one of the circumventricular organs (CVOs) of the mammalian nervous system responsible for maintaining the energy and water and sodium balance. Despite notable interest in the SFO and its physiological functions, the organization of individual populations of SFO cells, as well as their interactions remain to be clearly established. In this study we examined GABA and nitroxidergic systems of SFO using immunohistochemical (IHC) methods. The brain of male Wistar rats at different stages of postnatal development: postnatal day 7 (P7), 14 (P14) and adult (4–6 months), was examined. The data obtained allowed us to characterize changes in the activity of the GABA- and nitroxidergic systems of the SFO during development. In adult rats, three subpopulations of nitroxidergic cells, differing in the intensity of the reaction and tissue localization, can be distinguished. The revealed morphological heterogeneity of nitroxidergic cells in SFO may reflect their diverse functional status.

Asprosin modulates testicular functions during ageing in mice

Ageing is a gradual and multi-factorial process with a significant impact on fertility. The mechanism of declined testicular functions with age remains elusive. Asprosin is a novel fasting-induced gluconeogenic adipokine that regulates glucose homeostasis. However, the expression and potential role of asprosin in testicular functions with age are largely unexplored. So, the current study was aimed to examine the variation in asprosin expression in the mice testis and its correlation with OLFR734 receptor, insulin receptor (IR), GLUT-8 and various steroidogenic markers at different stages of postnatal development. The result demonstrated the highest expression of asprosin in reproductively active mice, which decreased significantly in aged mice testis. Asprosin expression declined simultaneously with declining testosterone production, testicular glucose and expression of OLFR734, IR, GLUT-8 and AR in aged mice testis. This suggests that declining asprosin expression with advancing age may be a causative factor for regressive changes in the testis. Further, the present study also evaluated the in vitro effect of asprosin on testicular functions of aged mice testis. The results showed that asprosin treatment improves testicular functions by stimulating the expression of OLFR734, StAR, 3β-HSD,17β-HSD, IR, GLUT-8, MCT-2&4, PCNA, Bcl2 proteins alongwith increased testosterone, insulin and lactate biosynthesis. Collectively, these findings indicate that a marked decline in asprosin and its receptor OLFR734 expression may result in decreased insulin sensitivity and glucose transport, leading to regressive changes in aged mice testis. Treatment of asprosin can possibly restore the testicular functions of aged mice by augmenting the testosterone, insulin and glucose levels.

Histological Study of the Harderian Gland of Pati Duck (Anas platyrhynchos domesticus) of Assam during Postnatal Development

Background: The farmers are rearing duck in small scale in semi intensive system without investing more capital but it contributes a major part to uplift the socio-economic condition of the rural poor people of Assam. The Pati duck (Anas platyrhynchos domesticus) population constitutes a major indigenous non-descript economically important duck variety in the state of Assam. The Harderian gland acts as a part of the head associated lymphoid tissue (HALT) and provides local innate immunity to the upper respiratory system, to the eye and oral cavity. Since literature on histological study of Harderian gland of Pati duck is scant, hence the present study was designed to establish the basic histological details on Harderian gland at different stages of postnatal development of Pati duck of Assam. Methods: The present study was conducted on total forty five (45) numbers Pati duck of Assam at different stages of postnatal development. The experimental birds were brought to the Department of Anatomy and Histology, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-22 and was sacrificed according to the method of Gracy (1986). For histological study the tissue samples from the Harderian gland of all the age group were fixed in 10% neutral buffered formalin solution and processed to prepare paraffin blocks as per the procedure described by Luna (1968). The paraffin blocks were sectioned in Shandon Finesse microtome in 5 µm thickness and the sections were stained by different methods as described by Luna (1968). Result: The Harderian gland of Pati duck had a capsule, the thickness of the capsule of the Harderian gland was increased slightly along the advancement of the age. The capsular connective tissue penetrated the parenchyma of the Harderian gland in the form of septa. The collagen, reticular, elastic and nerve fibers were observed along with the capsule and as well as in the septa. The Harderian gland of the Pati duck was compound tubular gland. The columnar epithelial cells lined the tubules. There was no cortex and medulla in the gland and the tubular structure were uniformly distributed within the lobules. A central canal was present in the gland which converged to the duct of the gland. The lymphocytes, plasma cells were found in the intertubular connective tissue. The numbers or population of plasma cell and lymphocytes were accelerated by the advancement of age. The myoepithelial cells with spindle shaped nucleus were present near the basement membrane close to the secretary cells. The histology of the duct of the Harderian gland of Pati duck was like that of typical hollow tubular organs. There were few lymphatic nodules very distinctly present extended from the lamina propria to the muscle layer.

Commentary on "Subcellular Fractions of Adult and Developing Rat Cerebellum, by M. del Cerro, R. S. Snider and M. L. Oster, July 1969".

Subcellular fractionation by differential ultracentrifugation has allowed the study of the cell and its organelles from a morphological, physiological, and biochemical perspective. Combined with electron microscopy, and by using animals at different stages of postnatal development, these methods yielded useful results concerning the ontogeny of synaptosomes, mitochondria, and myelin and broadened the possibilities to investigate the molecular underpinnings of cerebellar histogenesis.

Post Natal Gross Anatomical Studies on the Harderian Gland of Pati Duck (Anas platyrhynchos domesticus) of Assam

Background: The agro-climatic condition of Assam is suitable for duck rearing. Duck rearing contributes a major part to uplift the socio-economic condition of the rural poor people of Assam as well as others states located in the coastal regions of India. The Pati duck (Anasplatyrhynchos domesticus) population constitutes a major indigenous non-descript economically important duck variety in the state of Assam. The Harderian gland acts as a part of the Head Associated Lymphoid Tissue (HALT) Olah et al. (1992) and provides local innate immunity to the upper respiratory system, to the eye and oral cavity. Since literature on the postnatal development of Harderian gland of Pati duck is scant, hence the present study was designed to establish the basic anatomical details on Harderian gland at different stages of postnatal development of Pati duck of Assam. Methods: The present study was conducted on total forty five (45) numbers Pati duck of Assam at different stages of postnatal development. The experimental birds were brought to the Department of Anatomy and Histology, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-22 and was sacrificed according to the method of Gracy (1986). After slaughter, the birds were placed on a clean dissecting table and skin and fascia were reflected carefully without disturbing the other organs of the head region. The Harderian gland was collected by opening the orbital cavity. Thereafter, length, breadth and thickness of the Harderian gland of all age group were recorded with the help of the Vernier Callipers (McCance, 1974) and topographical location of the gland was observed. The weight of the Harderian gland of all age group was also recorded with the help of electronic balance. Result: The Harderian gland of Pati duck (Anas platyrhynchos domesticus) was located within the orbit. The gland was flat, oval and coma shaped with irregular border. The gland had two surfaces i.e. the parietal and visceral surfaces, two borders and two blunt poles. The parietal surface was found convex and attached to fascia covered by the nasal bones and interorbital septa. The visceral surface was concave and it was attached loosely to the eye ball with fascia. The lobes of the Harderian gland became more prominent with the advancement of the age. The gland was light pink in colour. The arterial blood and the venus drainage was by provided by the ophthalmic artery and vein, respectively. The slender branch of oculomotor nerve innervated the Harderian gland. The result reflected an ascending trend from 0 week age group to 42 week age group in regard to all the gross parameters. There were slight difference between left and right glands for all the gross parameters but such variations were not statistically significant (P greater than 0.05). Each lobe of the Harderian Gland of Pati duck (Anas platyrhynchos domesticus) had a single short duct which opened into the conjunctival sac at the base of the 3rd eyelid.

Sodium vitamin C transporter 2 orchestrates lactate metabolism in mouse Sertoli cells.

Transportation of vitamin C (also called ascorbic acid (AA)), an important water-soluble antioxidant and cofactor in testis, requires glucose transporter family (GLUTs) and sodium/vitamin C cotransporter family (SVCT1 and SVCT2). There is so far scant information vis-à-vis the functional roles of SVCTs in testis, although they possess higher affinity for transportation of AA compared to GLUTs. To analyze the biological effects of SVCT2 in testis, we assessed testicular expression of SVCT2 in different experimental settings and the effect of SVCT2 ablation on spermatogenesis. Persistent expression of SVCT2 was shown in the mouse testis at different stages of postnatal development, demonstrated on day 14 of testicular development in mice consistent with the appearance of pachytene spermatocytes during the first wave of spermatogenesis. Testicular expression of SVCT2 was enriched in the cytoplasm of murine Sertoli cells (SCs). We then showed that in vivo inhibition of SVCT2 in mouse testis significantly impaired male fertility by causing oligozoospermia and asthenospermia, which mainly stemmed from a deficiency in lactate production. By generating the TM4SVCT2-/- cells and by profiling TM4SVCT2-/- cells with a constitutively activated HIF-1α mutant, we demonstrated that SVCT2 deficiency led to impaired lactate synthesis and reduced expression of Ldha mRNA in SCs. Mechanistically, ablation of SVCT2 resulted in ubiquitination and subsequent degradation of HIF-1α protein in the FSH-stimulated SCs. Collectively, our data document a novel testicular site of action of SVCT2 in the control of lactate synthesis by SCs, probably via ubiquitination-dependent regulation of HIF-1α stability.

STRUCTURAL AND FUNCTIONAL CHARACTERISTICS OF MICROGLIA IN THE POSTNATAL RAT STRIATUM

The aim of this study was to evaluate the morphological and functional characteristics of microglial cells in the rat striatum at different stages of postnatal development. Using immunocytochemical methods and fluorescent microscopy, brain sections were analysed at each of the following postnatal ages: day 7 (n = 4), day 14 (n = 3), 4 to 6 months (n = 3). Different morphological and functional types of microglial cells were identified and characterized in details. It was noted that microglia activated during normal brain development do not contain vimentin, which is characteristic of stroke-activated microglia.

Abolition of prenatal lipopolysaccharide-induced reproductive disorders in rat male offspring by fulvestrant

During prenatal and early postnatal periods of development, multiple environmental factors have profound and long-lasting effects on the immune and reproductive functions. The aim of this study was to investigate the effects of maternal lipopolysaccharide (LPS) exposure (50mg/kg, i.p.) at day 12 of pregnancy and estradiol antagonist treatment (fulvestrant, 1.5mg/kg, s.c. in neck) at postnatal days 5-14 (PND5-14) with high estradiol levels on reproductive parameters in adult rat males. Serum steroid concentrations were measured in male offspring at PND80 by ELISA. Body, testis weights and ano-genital distance (AGD) were recorded at different stages of postnatal development. Testis was also processed to cytohistological studies at PND80. Our results demonstrate that body weight was decreased from PND14 to 30 after prenatal LPS treatment and was increased after fulvestrant treatment. AGD was decreased after prenatal LPS treatment and was increased after fulvestrant injections. Testis weight, testosterone level, seminiferous tubule diameter, and number of Sertoli and spermatid cells were also decreased in rats exposed prenatally to LPS and were restored to the normal control level after fulvestrant treatment. According to results, we can conclude that the development of sexual disorders in males after prenatal immune stress is potentiated by estradiol during the pre-pubertal period.

Regional and Developmental Differences in Na+ Currents in Vestibular Primary Afferent Neurons.

The vestibular system relays information about head position via afferent nerve fibers to the brain in the form of action potentials. Voltage-gated Na+ channels in vestibular afferents drive the initiation and propagation of action potentials, but their expression during postnatal development and their contributions to firing in diverse mature afferent populations are unknown. Electrophysiological techniques were used to determine Na+ channel subunit types in vestibular calyx-bearing afferents at different stages of postnatal development. We used whole cell patch clamp recordings in thin slices of gerbil crista neuroepithelium to investigate Na+ channels and firing patterns in central zone (CZ) and peripheral zone (PZ) afferents. PZ afferents are exclusively dimorphic, innervating type I and type II hair cells, whereas CZ afferents can form dimorphs or calyx-only terminals which innervate type I hair cells alone. All afferents expressed tetrodotoxin (TTX)-sensitive Na+ currents, but TTX-sensitivity varied with age. During the fourth postnatal week, 200–300 nM TTX completely blocked sodium currents in PZ and CZ calyces. By contrast, in immature calyces [postnatal day (P) 5–11], a small component of peak sodium current remained in 200 nM TTX. Application of 1 μM TTX, or Jingzhaotoxin-III plus 200 nM TTX, abolished sodium current in immature calyces, suggesting the transient expression of voltage-gated sodium channel 1.5 (Nav1.5) during development. A similar TTX-insensitive current was found in early postnatal crista hair cells (P5–9) and constituted approximately one third of the total sodium current. The Nav1.6 channel blocker, 4,9-anhydrotetrodotoxin, reduced a component of sodium current in immature and mature calyces. At 100 nM 4,9-anhydrotetrodotoxin, peak sodium current was reduced on average by 20% in P5–14 calyces, by 37% in mature dimorphic PZ calyces, but by less than 15% in mature CZ calyx-only terminals. In mature PZ calyces, action potentials became shorter and broader in the presence of 4,9-anhydrotetrodotoxin implicating a role for Nav1.6 channels in firing in dimorphic afferents.

Testosterone measured from amniotic fluid and maternal plasma shows no significant association with directional asymmetry in newborn digit ratio (2D:4D).

Foetal sex hormones can have powerful and far-reaching effects on later phenotype. However, obtaining accurate measurements is difficult for ethical reasons, and researchers often employ proxy variables to examine their effects. The relative length of the second and fourth fingers (digit ratio or 2D:4D) is frequently used for this purpose, as it is hypothesized to index variance in prenatal androgen and oestrogen exposure. Most studies employing this method examine digit ratio for the right hand (R2D:4D) and/or left hand (L2D:4D), though the mean value (M2D:4D) (i.e., the average of R2D:4D and L2D:4D) and directional asymmetry (D[R-L]) (i.e., R2D:4D minus L2D:4D) are also commonly used. As no published studies have examined M2D:4D or D[R-L] in relation to testosterone measured from amniotic fluid, we conducted a secondary analysis of data published by Ventura et al. The sample comprises 106 mothers from Portugal who underwent amniocentesis during the second trimester and their neonates. Newborn M2D:4D was negatively correlated with amniotic testosterone in females (P<0.05) but not in males; no significant association was observed between amniotic testosterone and D[R-L] in either sex. In addition, we examined testosterone measured from maternal circulation during the second trimester, and found that it was not a significant predictor of M2D:4D or D[R-L] in male or female infants. Further research should aim to measure the ratio of testosterone to oestradiol present in amniotic fluid and maternal plasma, to examine whether either is a predictor of digit ratio variables at different stages of postnatal development.

Development of a Novel FIJI-Based Method to Investigate Neuronal Circuitry in Neonatal Mice.

The emergence of systems neuroscience tools requires parallel generation of objective analytical workflows for experimental neuropathology. We developed an objective analytical workflow that we used to determine how specific autonomic neural lineages change during postnatal development. While a wealth of knowledge exists regarding postnatal alterations in respiratory neural function, how these neural circuits change and develop in the weeks following birth remains less clear. In this study, we developed our workflow by combining genetic mouse modeling and quantitative immunofluorescent confocal microscopy and used this to examine the postnatal development of neural circuits derived from the transcription factors NKX2.2 and OLIG3 into three medullary respiratory nuclei. Our automated FIJI-based image analysis workflow rapidly and objectively quantified synaptic puncta in user-defined anatomic regions. Using our objective workflow, we found that the density and estimated total number of Nkx2.2-derived afferents into the pre-Bötzinger Complex significantly decreased with postnatal age during the first three weeks of postnatal life. These data indicate that Nkx2.2-derived structures differentially influence pre-Bötzinger Complex respiratory oscillations at different stages of postnatal development.

Відмінності вмісту металотіонеїну у мозку гризунів за умов постнатального розвитку та кадмієвої інтоксикації

Introduction. Metal-binding metallothionein genes are found in a vast population of organisms. These proteins are non enzymatic and very rich in cysteine residues. The various metallothionein isoforms in different brain regions arguably change over time.The aim of the study – evaluating the distribution of metallothionein in different brain regions of gerbils and Wistar rats at different stages of postnatal development (PND), under standard and low dose Cd-induced conditions.Materials and Methods. 18 Mongolian gerbils and 36 Wistar rats were divided into 6 groups (n=6), by age and condition of experiment: groups 1, 2, 3, 4 – 1, 30, 90 and 180-days old were exposed to standard conditions; group 5 and 6 – 180-days old+0.1 or 1.0 µgµg Cd2+ per animal everyday for 36 days. The metallothionein content in the hippocampus, cerebellum, and thalamus were detected by the ELISA.Results and Discussion. Obtained data was shown the dynamic of metallothionein distribution in different brain regions of gerbils and Wistar rats depending on the stage of postnatal development and functional capacities. The content of metallothionein in the hippocampus continually decreased in both animal types but the cerebella metallothionein distribution pattern was different from that of the hippocampus, but identical in both rodents, rising from day one before decreasing on day 30. The low levels of metallothionein under the influence of Cd were proportional to the doses administered.Conclusions. The level of metallothionein in the brain varies depending on the stage of development of the functional capacities of the brain parts. The significant down-regulation of metallothionein in the investigated brain regions under Cd influence suggests that a decrease in metallothionein levels depends on the dose of Cd and on the time necessary for its accumulation.

GABAρ selective antagonist TPMPA partially inhibits GABA-mediated currents recorded from neurones and astrocytes in mouse striatum

The neostriatum plays a central role in motor coordination where nerve cells operate neuronal inhibition through GABAergic transmission. The neostriatum expresses a wide range of GABA-A subunits, including GABAρ1 and ρ2 which are restricted to a fraction of GABAergic interneurons and astrocytes. Spontaneous postsynaptic currents (sPSCs) evoked by 4-aminopyridine (4-AP) were recorded from neurones of the dorsal neostriatum, and their frequency was reduced > 50% by the selective GABAρ antagonist (1,2,5,6-Tetrahydropyridine-4-yl) methylphosphinic acid (TPMPA). Additionally, we recorded GABA evoked currents from astrocytes in vitro and in situ. Astrocytes in vitro showed modulation by pentobarbital and desensitization upon consecutive applications of GABA. However, modulation by pentobarbital was absent and no significant desensitization was detected from astrocytes in situ. Moreover, TPMPA-sensitive GABA-currents that were insensitive to bicuculline were also recorded from astrocytes in situ, consistent with our previous study where GABAρ expression was demonstrated. Finally, we assessed the mRNA expression of GABAρ3, through different stages of postnatal development; double immunofluorescence disclosed GABAρ3 expression in calretinin-positive interneurons as well as in astrocytes (>70%). These results add new information about the participation of GABAρ subunits in neostriatal interneurons and astrocytes.

Morphological and molecular aspects of immobilization-induced muscle atrophy in rats at different stages of postnatal development: the role of autophagy.

Muscle loss occurs following injury and immobilization in adulthood and childhood, which impairs the rehabilitation process; however, far fewer studies have been conducted analyzing atrophic response in infants. This work investigated first the morphological and molecular mechanisms involved in immobilization-induced atrophy in soleus muscles from rats at different stages of postnatal development [i.e., weanling (WR) and adult (AR) rats] and, second, the role of autophagy in regulating muscle plasticity during immobilization. Hindlimb immobilization for 10 days reduced muscle mass and fiber cross-sectional area, with more pronounced atrophy in WR, and induced slow-to-fast fiber switching. These effects were accompanied by a decrease in markers of protein synthesis and an increase in autophagy. The ubiquitin (Ub)-ligase MuRF1 and the ubiquitinated proteins were upregulated by immobilization in AR while the autolyzed form of μ-calpain was increased in WR. To further explore the role of autophagy in muscle abnormalities, AR were concomitantly immobilized and treated with colchicine, which blocks autophagosome-lysosome fusion. Colchicine-treated immobilized muscles had exacerbated atrophy and presented degenerative features. Despite Igf1/Akt signaling was downregulated in immobilized muscles from both age groups, Foxo1 and 4 phosphorylation was increased in WR. In the same group of animals, Foxo1 acetylation and Foxo1 and 4 content was increased and decreased, respectively. Our data show that muscle disorders induced by 10-day-immobilization occur in both age-dependent and -independent manners, an understanding that may optimize treatment outcomes in infants. We also provide further evidence that the strong inhibition of autophagy may be ineffective for treating muscle atrophy.

Localization and expression of Orexin A and its receptor in mouse testis during different stages of postnatal development

Orexin A (OXA), a hypothalamic neuropeptide, is involved in regulation of various biological functions and its actions are mediated through G-protein-coupled receptor, OX1R. This neuropeptide has emerged as a central neuroendocrine modulator of reproductive functions. Both OXA and OX1R have been shown to be expressed in peripheral organs such as gastrointestinal and genital tracts. In the present study, localization and expression of OXA and OX1R in mouse testis during different stages of postnatal development have been investigated. Immunohistochemical results demonstrated localization of OXA and OX1R in both the interstitial and the tubular compartments of the testis throughout the period of postnatal development. In testicular sections on 0day postpartum (dpp), gonocytes, Sertoli cells and foetal Leydig cells showed OXA and OX1R-immunopositive signals. At 10dpp, Sertoli cells, spermatogonia, early spermatocytes and Leydig cells showed immunopositive signals for both, the ligand and the receptor. On 30 and 90dpp, the spermatogonia, Sertoli cells, spermatocytes, spermatids and Leydig cells showed the OXA and OX1R-immunopositive signals. At 90dpp, strong OXA-positive signals were seen in Leydig cells, primary spermatocytes and spermatogonia, while OX1R-immunopositive intense signals were observed in Leydig cells and elongated spermatids. Further, semiquantitative RT-PCR and immunoblot analyses showed that OXA and OX1R were expressed in the testis both at transcript and protein levels during different stages of postnatal development. The expression of OXA and OX1R increased progressively from day of birth (0dpp) until adulthood (90dpp), with maximal expression at 90 dpp. The results suggest that OXA and OX1R are expressed in the testis and that they may help in proliferation and development of germ cells, Leydig cells and Sertoli cells, and in the spermatogenic process and steroidogenesis.

THE CHANGES OF GLIAL FIBRILLARY ACID PROTEIN LEVEL IN THE DIFFERENT BRAIN AREAS OF GERBILS UNDER DEVELOPMENT, AGING AND ALPHA-KETO GLUTARATE EFFECT

There has been shown the change of level of astrocytes-specific glial fibrillary acid protein (GFAP) in different areas of the brain of laboratory gerbils at different stages of postnatal development, aging, and the effect of lphaketoglutarate.Studies have shown that the content of both soluble and filament forms of GFAP significantly increased during the first 30 days of postnatal development in all parts of the brain. After 30 days, the level of soluble forms of GFAP continued gradualy increase in all studied brain areas of gerbils during development and aging. Content of filament forms of GFAP in the gerbils brain after 90 days has a different tendency to change depending on the brain region. The long-term diet containing 2% alpha-ketoglutarate has been prevented overproduction of filament form of GFAP in the thalamus and hippocampus of older animals.