Histological effect of nicotine on adrenal zona fasciculata and the effect of grape seed extract with or without withdrawal of nicotine

Changes in Rat Adrenal Cortex and Pineal Gland in Inverted Light-Dark Cycle: A Biochemical, Histological, and Immunohistochemical Study

Poor sleep standards are common in everyday life; it is frequently linked to a rise in stress levels. The adrenal gland interacts physiologically with the pineal gland in the stress response. Pineal gland is a small endocrine organ that modulates sleep patterns. This work aimed to evaluate the inverted light-dark cycle rhythm on the histological changes within the adrenal cortex and pineal gland in adult male albino rats. Twenty adult male albino rats were equally divided into two groups: For the first control group, animals were kept on daylight-darkness for 12-12 h. The second group was kept under an inverted 12- to 12-h light-darkness cycle for 4 weeks. Adrenal sections were subjected to biochemical, histological, and immunohistochemical study. Inverted light-dark cycle group recorded a significant elevation of plasma corticosterone, tissue malondialdehyde, tumor necrosis factor-α, and interleukin-1β (IL-1β) associated with a significant reduction of catalase and superoxide dismutase. Adrenal cortex showed biochemical and histological changes. Pineal glands also showed loss of lobular architecture. A significant upregulation in activated inducible nitric oxide synthase (iNOS) and B-cell lymphoma-associated X (Bax) immunohistochemical expression was recorded in adrenal cortex associating with downregulation in B-cell lymphoma 2 (Bcl-2). It could be concluded that subchronic inverted light-dark cycle exerted direct effects on adrenal cortex and the pineal glands.

Potential Disruption of Systemic Hormone Transport by Tobacco Alkaloids Using Computational Approaches

Tobacco/nicotine is one of the most toxic and addictive substances and continues to pose a significant threat to global public health. The harmful effects of smoking/nicotine affect every system in the human body. Nicotine has been associated with effects on endocrine homeostasis in humans such as the imbalance of gonadal steroid hormones, adrenal corticosteroid hormones, and thyroid hormones. The present study was conducted to characterize the structural binding interactions of nicotine and its three important metabolites, cotinine, trans-3'-hydroxycotinine, and 5'-hydroxycotinine, against circulatory hormone carrier proteins, i.e., sex-hormone-binding globulin (SHBG), corticosteroid-binding globulin (CBG), and thyroxine-binding globulin (TBG). Nicotine and its metabolites formed nonbonded contacts and/or hydrogen bonds with amino acid residues of the carrier proteins. For SHBG, Phe-67 and Met-139 were the most important amino acid residues for nicotine ligand binding showing the maximum number of interactions and maximum loss in ASA. For CBG, Trp-371 and Asn-264 were the most important amino acid residues, and for TBG, Ser-23, Leu-269, Lys-270, Asn-273, and Arg-381 were the most important amino acid residues. Most of the amino acid residues of carrier proteins interacting with nicotine ligands showed a commonality with the interacting residues for the native ligands of the proteins. Taken together, the results suggested that nicotine and its three metabolites competed with native ligands for binding to their carrier proteins. Thus, nicotine and its three metabolites may potentially interfere with the binding of testosterone, estradiol, cortisol, progesterone, thyroxine, and triiodothyronine to their carrier proteins and result in the disbalance of their transport and homeostasis in the blood circulation.

Harmine prevents 3-nitropropionic acid-induced neurotoxicity in rats via enhancing NRF2-mediated signaling: Involvement of p21 and AMPK

Oxidative stress induced neurotoxicity is increasingly perceived as an important neuropathologic mechanism underlying the motor and behavioral phenotypes associated with Huntington's disease (HD). Repeated exposure to 3-nitropropionic acid (3-NP) induces neurotoxic changes which closely simulate the neuropathological and behavioral characteristics of HD. This study aimed at evaluating the prophylactic effects of the dual-specificity tyrosine phosphorylation regulated kinase 1A (DYRK1A) inhibitor "harmine" against 3-NP-indued neurotoxicity and HD-like symptoms. The potential prophylactic effect of harmine (10 mg/kg/day; intraperitoneal) was investigated on 3-NP-induced motor and cognitive HD-like deficits, nuclear factor erythroid 2 like 2 (NRF2), AMP kinase (AMPK) and p21 protein levels and the gene expression of haem oxygenase-1 (Ho-1), NAD(P)H: quinone oxidoreductase-1 (Nqo-1) and p62 in addition to redox imbalance and histological neurotoxic changes in the striatum, prefrontal cortex, and hippocampus of male Wistar rats. Harmine successfully increased the protein levels of NRF2, AMPK and p21 and the gene expression of Ho-1, Nqo-1 and p62, restored redox homeostasis, and reduced CASPASE-3 level. This was reflected in attenuation of 3-NP-induced neurodegenerative changes and improvement of rats' motor and cognitive performance. This study draws attention to the protective role of harmine against 3-NP-induced motor and cognitive dysfunction that could be mediated via enhancing NRF2-mediated signaling with subsequent amelioration of oxidative stress injury via NRF2 activators, p21 and AMPK, in the striatum, prefrontal cortex, and hippocampus which could offer a promising therapeutic tool to slow the progression of HD.

Protective effect of grape seed extract against chronic physical stress-induced zona fasciculata injury in male rats: Functional, immunohistochemical and electron microscopic study

In the present study, we investigated the antioxidant effect of grape seed extract (GSE) against chronic immobilization stress-induced zona fasciculata injury in Wistar male rats. Thirty male rats were divided into three groups: Non-stress group: rats were not subjected to stress protocol and received distilled water orally for 30 days. Stress group: rats received distilled water orally for 15 consecutive days before the induction of chronic immobilization stress experiment (repeated stress for 15 consecutive days), distilled water was continued along with the constant stress experiment. GSE-stress group: rats treated with oral GSE (300 mg/kg), administered orally for 15 consecutive days before the induction of chronic immobilization stress experiment (repeated stress for 15 consecutive days), GSE was continued along with the stress exposure. Chronic stress was induced by placing each animal in a restrainer for 2 h daily for 15 consecutive days in both Stress and GSE-stress groups. The serum corticosterone and adrenal cortex malondialdehyde (MDA) levels were measured as indices of stress. Immunohistochemistry of the inducible nitric oxide synthase (iNOS) as a nitrosative stress marker beside the adrenal cortex's ultrastructure, particularly zona fasciculata, was assessed. Chronic restraint stress significantly elevated the serum corticosterone and adrenal cortex MDA levels, while oral administration of GSE reduced the serum corticosterone level, adrenal cortex MDA levels, and iNOS immunoreactivity in zona fasciculata. Besides, adrenocortical ultrastructure significantly improved. These results suggested that GSE enhanced the antioxidant defense against reactive oxygen species produced under chronic stress conditions, protecting the adrenal cortex.

Tramadol Promotes Oxidative Stress, Fibrosis, Apoptosis, Ultrastructural and Biochemical alterations in the Adrenal Cortex of Adult Male Rat with Possible Reversibility after Withdrawal

Tramadol is a centrally acting analgesic drug, used for the management of moderate to severe pain in a variety of diseases. The long-term use of tramadol can induce endocrinopathy. This study aimed to evaluate the effect of tramadol dependence on the adrenal cortex and the effect of its withdrawal. Thirty adult male rats were divided into three experimental groups: the control group, the tramadol-dependent group that received increasing therapeutic doses of tramadol orally for 1 month, and the recovery group that received tramadol in a dose and duration similar to the previous group followed by a withdrawal period for another month. Specimens from the adrenal cortex were processed for histological, immunohistochemical, enzyme assay, and quantitative real-time PCR (RT-qPCR) studies. Tramadol induced a significant increase in malondialdehyde level and a significant decrease in the levels of glutathione peroxidase and superoxide dismutase. A significant decrease in the levels of adrenocorticotrophic hormones, aldosterone, cortisol, corticosterone, and dehydroepiandrosterone sulfate was also detected. Severe histopathological changes in the adrenal cortex were demonstrated in the form of disturbed architecture, swollen cells, and shrunken cells with pyknotic nuclei. Inflammatory cellular infiltration and variable-sized homogenized areas were also detected. A significant increase in P53 and Bax immunoreaction was detected and confirmed by RT-qPCR. The ultrastructural examination showed irregular, shrunken adrenocorticocytes with dense nuclei. Dilated smooth endoplasmic reticulum, mitochondria with disrupted cristae, and numerous coalesced lipid droplets were also demonstrated. All these changes started to return to normal after the withdrawal of tramadol. Thus, it was confirmed that the long-term use of tramadol can induce severe adrenal changes with subsequent insufficiency.