Rat Adrenal Gland Research Articles

Expression of tryptophan hydroxylase in rat adrenal glands: Upregulation of TPH2 by chronic stress

It has been shown that chronic restraint stress (CRS) increases adrenal 5-HT levels and turnover through a mechanism that appears unrelated to tryptophan hydroxylase (TPH). In the present study we re-analyzed the effects of CRS (20 min/day) for 14 days relative to control (CTRL) conditions on TPH expression, distribution, and activity in rat adrenal glands. On day 15, adrenal glands were collected for TPH1 and TPH2 immunohistochemistry, Western blot, and RT-PCR; TPH activity was estimated by quantification of 5-hydroxytryptophan (5-HTP) and, indirectly, through measurement of 5-HT and 5-hydroxindolacetic acid (5-HIAA) levels and turnover (5-HIAA/5-HT ratio) by HPLC. TPH expression and activity in the dorsal raphe nucleus (DRN) were also determined for comparison. TPH1 and TPH2 immunostaining was observed in the adrenal medulla, and measurable levels of TPH1 and TPH2 protein and mRNA were detected in rat adrenal glands from CTRL animals. CRS exposure noticeably increased TPH2- but not THP1-immunostaining in the medulla and the outer adrenocortical areas of left (LAG) but not of right adrenal glands (RAG). In addition, CRS exposure increased TPH2 protein and mRNA levels in LAG; however, both measures decreased in DRN. Finally, CRS treatment produced an increase and a decrease of TPH activity and 5-HT turnover in LAG and DRN, respectively. Results indicate that TPH is indeed expressed in rat adrenal glands. Exposure to CRS upregulates TPH2 in LAG, while inducing downregulation of it in the DRN. Then, the increased levels of 5-HT in LAG from CRS-exposed animals likely results from TPH2-mediated synthesis.

The α3β4 nAChR tissue distribution identified by fluorescent α-conotoxin [D11A]LvIA

α3β4, a vital subtype of neuronal nicotinic acetylcholine receptors (nAChRs), is widely distributed in the brain, ganglia, and adrenal glands, associated with addiction and neurological diseases. However, the lack of specific imaging tools for α3β4 nAChRs has hindered the investigation of their tissue distribution and functions. [D11A]LvIA, a peptide derived from marine cone snails, demonstrates high affinity and potency for α3β4 nAChRs, making it a valuable pharmacological tool for studying this receptor subtype. In this study, three fluorescent conjugates of [D11A]LvIA were synthesized using 6-TAMRA-SE (R), Cy3-NHS-ester (Cy3), and BODIPY-FL NHS ester (BDP) dyes. The electrophysiological activities were assessed in Xenopus laevis oocytes by two-electrodes voltage clamp (TEVC). [D11A]LvIA-Cy3 and [D11A]LvIA-BDP show improved selectivity and affinity, with IC50 values of 512.70 nM and 343.50 nM, respectively, and [D11A]LvIA-Cy3 exhibits better stability in cerebrospinal fluid (CSF). Utilizing [D11A]LvIA-Cy3, we successfully visualized the distribution of α3β4 nAChRs in rat trigeminal ganglia, retina, adrenal glands, and various brain regions. This novel fluorescent peptide provides a significant pharmacological tool for the exploration and visualization in-situ distribution of α3β4 nAChRs in different tissues and also assists in clarifying the function.

Near-Infrared Emissive Super Penetrating Conjugated Polymer Dots for Intratumoral Imaging in 3D Tumor Spheroid Models.

This study describes the formation of single-chain polymer dots (Pdots) via ultrasonic emulsification of nonionic donor-acceptor-donor type (D-A-D) alkoxy thiophene-benzobisthiadiazole-based conjugated polymers (Poly BT) with amphiphilic cetyltrimethylammonium bromide (CTAB). The methodology yields Pdots with a high cationic surface charge (+56.5mV ± 9.5) and average hydrodynamic radius of 12nm. Optical characterization reveals that these Pdots emit near-infrared (NIR) light at a maximum wavelength of 860nm owing to their conjugated polymer backbone consisting of D-A-D monomers. Both colloidal and optical properties of these Pdots make them promising fluorescence emissive probes for bioimaging applications. The significant advantage of positively charged Pdots is demonstrated in diffusion-limited mediums such as tissues, utilizing human epithelial breast adenocarcinoma, ATCC HTB-22 (MCF-7), human bone marrow neuroblastoma, ATCC CRL-2266 (SH-SY5Y), and rat adrenal gland pheochromocytoma, CRL-1721 (PC-12)tumor spheroid models. Fluorescence microscopy analysis of tumor spheroids from MCF-7, SH-SY5Y, and PC-12 cell lines reveals the intensity profile of Pdots, confirming extensive penetration into the central regions of the models. Moreover, a comparison with mitochondria staining dye reveals an overlap between the regions stained by Pdots and the dye in all three tumor spheroid models. These results suggest that single-chain D-A-D type Pdots, cationized via CTAB, exhibit long-range mean free path of penetration (≈1µm) in dense mediums and tumors.

Impact of Aging on the Morphology of the Adrenal Gland in Rats

Impact of Aging on the Morphology of the Adrenal Gland in Rats

Dexmedetomidine on the interplay of IL-6 and STAT3 pathways in adrenal gland damage-induced scalding burns in rats.

Scalding burns are a common form of thermal injury that often leads to systemic complications. Pro-inflammatory cytokines like interleukin-6 (IL-6) and the activation of signal transducer and activator of transcription 3 (STAT3) pathways have been linked to the pathophysiology of organ damage caused by burns. This study aimed to investigate the potential therapeutic effects of dexmedetomidine, an α2-adrenergic receptor agonist with anti-inflammatory properties, on the interplay of IL-6 and STAT3 pathways in adrenal gland damage following scalding burns in rats. Twenty-eight rats were divided randomly into four groups. Rats in group 1 (n=7, control) were given only 0.9% intraperitoneal (i.p.) NaCl. Rats in group 2 (n=7, DEX) were exposed to 25°C water for 17 s on day 1 and received 100 mcg/kg/day dexmedetomidine i.p. for 3 days; for rats in group 3 (n=7, Burn), boiling water of 94°C was applied inside for 17 s. Rats in group 4 (n=7, Burn+DEX) were exposed to 94°C water for 17 s and received 100 mcg/kg/day dexmedetomidine i.p. for 3 days. Adrenal gland tissues were histopathological examined, and STAT3, IL-6, and TUNEL staining were performed using immunohistochemically. Our results revealed that scalding burns increased IL-6 and STAT3 expression in the adrenal glands of rats. Histological analysis demonstrated that dexmedetomidine administration ameliorated adrenal gland damage and reduced inflammatory cell infiltration. Our findings suggest that dexmedetomidine protects the adrenal glands in scalding burns. This protection appears to be mediated, at least in part, by its modulation of IL-6 and STAT3 pathways.

Ultrastructural changes in the adrenal gland in terms of age and gender-related

Objectives: The adrenal glands are endocrine organs that synthesise hormones with crucial functions in the body. This irreplaceable structure performs multiple functions, from metabolism of carbohydrates, fats and proteins to sex development. Any disorder concerning the adrenal glands can give rise to life-threatening conditions. The aging process inevitably affects the adrenal glands. The effects of ageing are marked by a rise in cortisol secretion in the zona fasciculata and a decrease in androgen secretion in the zona reticularis. Elevated cortisol levels in the blood disturb most bodily systems in favour of catabolism, amplifying the cellular decline and destruction that accompanies ageing. The deterioration of the adrenal glands relates not just to spongiocytes and chromaffin cells, but also to the endothelium, which enables circulation. It is clear that a decline in vascular function will have a negative impact on endocrine activities. Our study aims to explore the influence of ageing on the adrenal glands in rats, analysing sex-specific ultrastructural scales. Materials and Methods: A total of 28 Sprague-Dawley rats, 14 males and 14 females, were planned to be used in the study. Of these 28 rats, 4 females and 4 males will constitute the control group. The rats in the control group will be approximately 10 weeks old, and the rats in the experimental group, which will represent the aged group, will be 19 weeks old. All animals in the study will be anaesthetised and then sacrificed by removal of the heart. The right and left common carotid arteries were removed from the sacrificed animals. Collected vessels prepared for TEM examination. For each animal, at least four TEM images were taken from four different sections from the same block. Results: Our findings demonstrate that the ageing process not only affects spongiocytes within the adrenal gland, but also contributes to the deterioration of endothelial cells. As anticipated, our results indicate the presence of senescence and apoptosis in endothelial cells. The observed vascular separations and ruptures are due to the endothelial deterioration. Spongiocytes experienced hypertrophy to compensate for the functional deficiencies following a decrease in their number due to ageing. Elevated levels of lipofuscin, lipid droplets, and lysosomes were discovered in spongiocytes. Impaired endothelium potentially contributes to certain changes in spongiocytes. Conclusions: While ageing-related changes appear similar in both genders, males tend to be more impacted.

Impact of Prenatal LPS and Early-life Constant Light Exposure on Circadian Gene Expression Profiles in Various Rat Tissues

Exposure to lipopolysaccharide (LPS) during prenatal development leads to various changes in neurobiological and behavioural patterns. Similarly, continuous exposure to constant light (LL) during the critical developmental period of the circadian system affects gene expression in various tissues in adulthood. Given the reciprocal nature of the interaction between the circadian and the immune systems, our study primarily investigated the individual effects of both interventions and, more importantly, their combined effect. We aimed to explore whether there might be a potential synergistic effect on circadian rhythms and their parameters, focussing on the expression of clock genes, immune-related genes, and specific genes in the hippocampus, pineal gland, spleen and adrenal gland of rats at postnatal day 30. Our results show a significant influence of prenatal LPS and postnatal LL on the expression profiles of all genes assessed. However, the combination of prenatal LPS and postnatal LL only revealed an enhanced negative effect in a minority of the comparisons. In most cases, it appeared to attenuate the changes induced by the individual interventions, restoring the measured parameters to values closer to those of the control group. In particular, genes such as Nr1d1, Aanat and Tph1 showed increased amplitude in the pineal gland and spleen, while the kynurenine enzymes Kynu and KatII developed circadian rhythmicity in the adrenal glands only after the combined interventions. Our data suggest that a mild immunological challenge during prenatal development may play a critical role in triggering an adaptive response of the circadian clock later in life.

Comparative assessment of CacyBP/SIP, β-catenin and cannabinoid receptors in the adrenals of hypertensive rats.

Taking into account homeostatic disorders resulting from arterial hypertension and the key importance of CacyBP/SIP, β-catenin and endocannabinoids in the functioning of many organs, it was decided to assess the presence and distribution of CacyBP/SIP, β-catenin, CB1 and CB2 in the adrenal glands of hypertensive rats of various aetiology. The study was conducted on the adrenal glands of rats with spontaneous and renovascular hypertension. The expression of CacyBP/SIP, β-catenin, CB1 and CB2 was detected by immunohistochemistry and real-time PCR method. The results of the present study revealed both lower gene expression and immunoreactivity of CacyBP/SIP in the adrenal glands of all hypertensive groups compared to the normotensive rats. This study demonstrated a reduction in the immunoreactivity and expression of the β-catenin, CB1 and CB2 genes in the adrenals of 2K1C rats. While in SHR, the reaction showing β-catenin and CB1 was very weak or negative, and the expression of CB2 in the adrenal glands of these rats increased. The results of this study show, for the first time, marked differences in the expression of CacyBP/SIP, β-catenin and CB1 and CB2 cannabinoid receptors in the adrenal glands of rats with primary (SHR) and secondary hypertension (2K1C).

Ameliorative Effect of Cinnamon against Hypercholesterolemia Induced by High-Fat Diet in The Adult Male Albino Rat's Adrenal Gland; Histological, Ultrastructural, and Immunohistochemical Studies

Ameliorative Effect of Cinnamon against Hypercholesterolemia Induced by High-Fat Diet in The Adult Male Albino Rat's Adrenal Gland; Histological, Ultrastructural, and Immunohistochemical Studies

Morphological Changes in the Adrenal Glands of Rats with Different Individual Typological Behavioral Features in a PTSD Model after Dalargin Injections

Morphological Changes in the Adrenal Glands of Rats with Different Individual Typological Behavioral Features in a PTSD Model after Dalargin Injections

Evaluation of the Expression and Localization of the Multifunctional Protein CacyBP/SIP and Elements of the MAPK Signaling Pathway in the Adrenal Glands of Rats with Primary and Secondary Hypertension.

Hypertension is a global civilization disease and one of the most common causes of death in the world. Organ dysfunction is a serious health consequence of hypertension, which involves damage to the heart, kidneys and adrenals. The interaction of recently discovered multifunctional protein-CacyBP/SIP with ERK1/2 and p38 kinases by regulating the activity and intracellular localization of these kinases may play an important role in the signaling pathways involved in the pathogenesis of hypertension. Due to the lack of data on this subject, we decided to investigate the localization, expression and possible relationship between the studied parameters in the adrenals under arterial hypertension. The study was conducted on the adrenals of rats with spontaneous and DOCA-salt hypertension. The expression of CacyBP/SIP, p-ERK1/2 and p-p38 was detected by immunohistochemistry and qRT-PCR. The results show a statistically significant decrease in CacyBP/SIP expression in the adrenal glands of hypertensive rats. With ERK1/2, there was a decrease in cortical immunoreactivity and an increase in the adrenal medulla of primary hypertensive rats. In contrast, in the adrenals of DOCA-salt rats, ERK1/2 immunoreactivity increased in the cortex and decreased in the medulla. In turn, p38 expression was higher in the adrenal glands of rats with primary and secondary hypertension. The obtained results may suggest the involvement of CacyBP/SIP in the regulation of signaling pathways in which MAP kinases play an important role and provide new insight into molecular events in hypertension. Moreover, they show the participation of CacyBP/SIP in response to oxidative stress.

Does Dactyloctenium aegyptium ethanolic extract protect against hormonal, histological and immunohistochemical alterations induced by sodium fluoride in rat adrenal gland?

ABSTRACT This work aimed to perform a biochemical, histological, and immunohistochemical assessment of the influence of sodium fluoride on the adrenal gland of rats and the possible ameliorating role of Dactyloctenium aegyptium (D. aegyptium). Thirty-five male albino rats were divided into five equal groups: group I served as the control group, group II received sodium fluoride (5 mg/kg), group III received D. aegyptium (200 mg/kg), and groups IV and V received sodium fluoride and D. aegyptium (100 and 200 mg/kg respectively) simultaneously for 28 days. Aldosterone, corticosterone, nitric oxide, sodium, potassium, and chloride were measured in serum samples. Adrenal gland specimens were processed for histological, histochemical, and immunohistochemical studies. The sodium fluoride group recorded a significant reduction in serum levels of aldosterone, corticosterone, potassium, and chloride (p ≤ 0.0001) and a significant increase in nitric oxide (p ≤ 0.0001) and serum sodium (p = 0.0076) when compared with the control group. Histological changes in the sodium fluoride treated group showed cytoplasmic vacuolation, scattered apoptotic cells, and hemorrhage. The sodium fluoride treatment significantly decreased glycogen (p = 0.0002), total protein) p = 0.0007), and DNA (p ≤ 0.0001) and increased inducible nitric oxide synthase (p = 0.0001). Co-treated groups with D. aegyptium showed almost average values for most parameters and a nearly standard architecture. The present data answers the question of our research that D. aegyptium ethanolic extract could protect against sodium fluoride’s adverse effects in rat adrenal glands on the physiological and histological levels.

Dapagliflozin downregulates G protein-coupled receptor Kinase-2 and upregulates regulator of g protein signaling-4 in adrenals to exert sympatholysis in heart failure

Abstract Dapagliflozin is a sodium-glucose co-transporter (SGLT)-2 inhibitor with beneficial cardiovascular effects independent of its anti-diabetic actions. Among these is sympatholysis, i.e., norepinephrine (NE) lowering which is beneficial in chronic human heart failure (HF). Adrenal G protein-coupled receptor kinase (GRK)-2 upregulation is a major driver of circulating catecholamine (CA) elevation and sympathetic nervous system (SNS) hyperactivity in HF due to dysregulation of adrenal sympatho-inhibitory α2-adrenergic receptors (ARs) [1]. On the other hand, we recently reported that signaling by neuronal free fatty acid receptor (FFAR)-3, which stimulates NE release from sympathetic neurons, is blocked by Regulator of G protein Signaling (RGS)-4 [2,3]. We hypothesized herein that dapagliflozin may lower SNS hyperactivity in the adrenal gland by improving α2AR, and antagonizing FFAR3 signaling in adrenal chromaffin cells. We used the rat pheochromocytoma PC12 cell line expressing human α2A-AR, as well as freshly isolated adrenal glands from rats treated with dapagliflozin in vivo. Dapagliflozin treatment for 7 consecutive days (20 mg/kg/d in drinking water) led to a significant reduction in blood circulating NE levels (217+67 pg/ml, n=6), compared to control, vehicle-treated rats (363+77 pg/ml, n=6, p<.05), suggesting reduced SNS activity. This was accompanied by reduced GRK2 and tyrosine hydroxylase (TH) mRNA and protein levels in dapagliflozin-treated rat adrenals vs. vehicle-treated animal-derived glands. In contrast, RGS4 mRNA levels were increased in dapagliflozin-treated adrenals. Adrenal α2AR density was higher in dapagliflozin- vs. vehicle-treated rats (51.3+7.3 vs. 26.1+8.1 fmol/mg of protein, respectively; n=12 glands from 6 animals per group, p<.05). These results (i.e., GRK2 & TH downregulation with RGS4 upregulation) were completely recapitulated in PC12 cells in culture, treated with 5 microM dapagliflozin (or vehicle) for 24 hours. Importantly, α2AR-dependent G protein-mediated signaling towards inhibition of CA secretion was markedly enhanced, whereas FFAR3-dependent phospholipase C/calcium signaling was reduced, at 24 hrs post-dapagliflozin treatment of PC12 cells. GRK2 overexpression partially reversed dapagliflozin`s effect on cholinergic-induced CA secretion. In conclusion, dapagliflozin exerts a sympatholytic action in the adrenal medulla via a) downregulation of TH, which reduces CA biosynthesis, and GRK2, which reduces α2AR desensitization; and b) upregulation of RGS4 to block FFAR3-stimulated CA secretion (Figure).Figure

Muscarinic Receptor Stimulation Does Not Inhibit Voltage-dependent Ca2+ Channels in Rat Adrenal Medullary Chromaffin Cells.

Adrenal medullary chromaffin (AMC) and sympathetic ganglion cells are derived from the neural crest and show a similar developmental path. Thus, these two cell types have many common properties in membrane excitability and signaling. However, AMC cells function as endocrine cells while sympathetic ganglion cells are neurons. In rat sympathetic ganglion cells, muscarinic M1 and M4 receptors mediate excitation and inhibition via suppression of M-type K+ channels and suppression of voltage-dependent Ca2+ channels, respectively. On the other hand, M1 receptor stimulation in rat AMC cells also produces excitation by suppressing TWIK-related acid sensitive K+ (TASK) channels. However, whether M4 receptors are coupled with voltage-dependent Ca2+ channel suppression is unclear. We explore this issue electrophysiologically and biochemically. Electrical stimulation of nerve fibers in rat adrenal glands trans-synaptically increased the Ca2+ signal in AMC cells. This electrically evoked increased Ca2+ signal was not altered during muscarine-induced increase in Ca2+ signal, whereas it decreased significantly during a GABA-induced increase, due to a shunt effect of increased Cl- conductance. The whole-cell current recordings revealed that voltage-dependent Ca2+ currents in AMC cells were suppressed by adenosine triphosphate, but not by muscarinic agonists. The fractionation analysis and immunocytochemistry indicated that CaV1.2 Ca2+ channels and M4 receptors are located in the raft and non-raft membrane domains, respectively. We concluded that muscarinic stimulation in rat AMC cells does not produce voltage-dependent Ca2+ channel inhibition. This lack of muscarinic inhibition is at least partly due to physical separation of voltage-dependent Ca2+ channels and M4 receptors in the plasma membrane.

Impact of Classic Adrenal Secretagogues on mRNA Levels of Urotensin II and Its Receptor in Adrenal Gland of Rats.

Urotensin 2 (Uts2) is a biologically active peptide involved in the regulation of a variety of physiological and pathophysiological processes. In both the human and rat adrenal gland, the expressions of the Uts2 gene and its receptor (Uts2r) have been described. This paper focuses on the description of the hormonal control of the mRNA levels of urotensin II and its receptor in the adrenal gland of the rat, both in vitro and in vivo. The initial in vitro experiments were carried out on freshly isolated rat adrenocortical cells and their primary culture. The obtained results indicated a stimulating PKA-independent effect of ACTH on the Uts2 mRNA level in the tested cells, with no changes in the Uts2r transcript. Subsequent in vivo experiments showed that ACTH-induced adrenal growth was accompanied by an elevated level of the Uts2 mRNA, with unchanged expression of Uts2r. In the other types of in vivo gland growth studied, enucleation-induced adrenal regeneration and compensatory growth of the gland, the mRNA levels of the studied genes showed no significant differences. The only exception was hemiadrenalectomy, which led to a significant increase in Uts2 mRNA expression level 24 h after surgery. In 12-week-old rats of both sexes, gonadectomy led to a significant increase in the level of Uts2 mRNA in the adrenal gland, an effect that was prevented by sex hormones' replacement. No changes in Uts2r transcript levels were observed under these conditions. Thus, this study suggests that the regulation of Uts2 and Uts2r mRNA levels differs significantly in the rat adrenal gland. While Uts2 transcript levels appear to be mainly dependent on ACTH action, Uts2r mRNA levels are not under the control of this hormone.

Transcranial Direct Current Stimulation (tDCS) Promotes state-dependent Effects on Neuroinflammatory and Behavioral Parameters in rats Chronically Exposed to Stress and a Hyper-Palatable Diet.

Chronic stress is a common condition affecting health, often associated with unhealthy eating habits. Transcranial direct current stimulation (tDCS) has been proposed to address these issues. Thus, this research investigated the effects of tDCS on biometric, behavioral, and neurochemical parameters in chronically stressed rats fed a hyper-palatable cafeteria diet (CAFD). The study lasted 8 weeks, with CAFD exposure and/or chronic restraint stress model (CRS - 1h/day, 5 days/week, for 7 weeks) started concurrently. tDCS or sham sessions were applied between days 42 and 49 (0.5mA, 20min/day). CAFD increased body weight, caloric consumption, adiposity, and liver weight. It also altered central parameters, reducing anxiety and cortical levels of IL-10 and BDNF. In turn, the CRS resulted in increased adrenals in rats with standard diet (SD), and anxiety-like and anhedonic behaviors in rats with CAFD. tDCS provided neurochemical shifts in CAFD-fed stressed rats increasing central levels of TNF-α and IL-10, while in stressed rats SD-fed induced a decrease in the adrenals weight, relative visceral adiposity, and serum NPY levels. These data demonstrated the anxiolytic effect of CAFD and anxiogenic effect of stress in CAFD-fed animals. In addition, tDCS promoted state-dependent effects on neuroinflammatory and behavioral parameters in rats chronically exposed to stress and a hyper-palatable diet. These findings provide primary evidence for additional mechanistic and preclinical studies of the tDCS technique for stress-related eating disorders, envisioning clinical applicability.

Transcriptome Profile of the Rat Adrenal Gland: Parenchymal and Interstitial Cells.

The homeostasis of the adrenal gland plays a decisive role in its proper functioning, both in non-stressful conditions and under the influence of various types of stress. This consists of interactions between all types of cells that make up the organ, including parenchymal and interstitial cells. The amount of available information on this subject in the rat adrenal glands under non-stressful conditions is insufficient; the aim of the research was to determine the expression of marker genes for rat adrenal cells depending on their location. The material for the study consisted of adrenal glands taken from intact adult male rats that were separated into appropriate zones. Transcriptome analysis by means of Affymetrix® Rat Gene 2.1 ST Array was used in the study, followed by real-time PCR validation. Expression analysis of interstitial cell marker genes revealed both the amount of expression of these genes and the zone in which they were expressed. The expression of marker genes for fibroblasts was particularly high in the cells of the ZG zone, while the highest expression of specific macrophage genes was observed in the adrenal medulla. The results of this study, especially with regard to interstitial cells, provide a so far undescribed model of marker gene expression of various cells, both in the cortex and medulla of the sexually mature rat adrenal gland. The interdependence between parenchymal and interstitial cells creates a specific microenvironment that is highly heterogeneous within the gland with respect to some of the interstitial cells. This phenomenon most likely depends on the interaction with the differentiated parenchymal cells of the cortex, as well as the medulla of the gland.

Differences in the extracellular matrix protein signature of the outermost zone of the rat adrenal gland

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Magnesium Supplementation Alleviates the Toxic Effects of Silica Nanoparticles on the Kidneys, Liver, and Adrenal Glands in Rats.

Concerns regarding the possible hazards to human health have been raised by the growing usage of silica nanoparticles (SiNPs) in a variety of applications, including industrial, agricultural, and medical applications. This in vivo subchronic study was conducted to assess the following: (1) the toxicity of orally administered SiNPs on the liver, kidneys, and adrenal glands; (2) the relationship between SiNPs exposure and oxidative stress; and (3) the role of magnesium in mitigating these toxic effects. A total of 24 Sprague Dawley male adult rats were divided equally into four groups, as follows: control group, magnesium (Mg) group (50 mg/kg/d), SiNPs group (100 mg/kg/d), and SiNPs+ Mg group. Rats were treated with SiNPs by oral gavage for 90 days. The liver transaminases, serum creatinine, and cortisol levels were evaluated. The tissue malondialdehyde (MDA) and reduced glutathione (GSH) levels were measured. Additionally, the weight of the organs and the histopathological changes were examined. Our results demonstrated that SiNPs exposure caused increased weight in the kidneys and adrenal glands. Exposure to SiNPs was also associated with significant alterations in liver transaminases, serum creatinine, cortisol, MDA, and GSH. Additionally, histopathological changes were significantly reported in the liver, kidneys, and adrenal glands of SiNPs-treated rats. Notably, when we compared the control group with the treated groups with SiNPs and Mg, the results revealed that magnesium could mitigate SiNPs-induced biochemical and histopathologic changes, confirming its effective role as an antioxidant that reduced the accumulation of SiNPs in tissues, and that it returns the levels of liver transaminases, serum creatinine, cortisol, MDA, and GSH to almost normal values.

Morphofunctional State of the Adrenal Glands in Rats under Urethane and Selenium Administration

The adrenal gland is one of the first organs to respond to external influences. Cortisol, with its important properties affecting the immune system, proliferation and apoptosis in various tissues, is a significant indicator of such a pathological process as malignant growth. Selenium is a powerful antioxidant having an immunomodulatory action and exhibiting anticarcinogenic effects. In this paper, we investigate adrenal morphofunctional changes under experimental carcinogenesis against the background of urethane and selenium administration by determining blood cortisol concentrations and studying the aggregate morphometric index of adrenal glands. The study revealed that carcinogen introduction imitates the adaptation syndrome stages in the organism and is accompanied by changes in the cortisol level and aggregate morphometric index. Maximal values of the studied parameters were detected after 1 month of exposure to carcinogen, which indicated the development of the alarm phase. A further decrease in the indices after 2 and 3 months down to the intact level indicates the development of the resistance stage. A sharp decrease in the indices after 6 months shows the exhaustion stage. An isolated course introduction of selenium leads to a reliable decrease in the aggregate morphometric index practically in all terms that indicates the stress-relieving influence of the microelement. The combined effects of selenium and carcinogen revealed a dropout of the alarm stage, but rapid elimination of the micronutrient from the body could not prevent the development of the exhaustion phase after 6 months.