Long‐term ethanol consumption promotes changes in β‐defensin isoform gene expression and induces structural changes and oxidative DNA damage to the epididymis of rats

Uncovering the impact of alcohol on internal organs and reproductive health: Exploring TLR4/NF-kB and CYP2E1/ROS/Nrf2 pathways

This review delves into the detrimental impact of alcohol consumption on internal organs and reproductive health, elucidating the underlying mechanisms involving the Toll-like receptor 4 (TLR4)/Nuclear factor kappa light chain enhancer of activated B cells (NF-kB) pathway and the Cytochrome P450 2E1 (CYP2E1)/reactive oxygen species (ROS)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathways. The TLR4/NF-kB pathway, crucial for inflammatory and immune responses, triggers the production of pro-inflammatory agents and type-1 interferon, disrupting the balance between inflammatory and antioxidant responses when tissues are chronically exposed to alcohol. Alcohol-induced dysbiosis in gut microbes heightens gut wall permeability to pathogen-associated molecular patterns (PAMPs), leading to liver cell infection and subsequent inflammation. Concurrently, CYP2E1-mediated alcohol metabolism generates ROS, causing oxidative stress and damaging cells, lipids, proteins, and deoxyribonucleic acid (DNA). To counteract this inflammatory imbalance, Nrf2 regulates gene expression, inhibiting inflammatory progression and promoting antioxidant responses. Excessive alcohol intake results in elevated liver enzymes (ADH, CYP2E1, and catalase), ROS, NADH, acetaldehyde, and acetate, leading to damage in vital organs such as the heart, brain, and lungs. Moreover, alcohol negatively affects reproductive health by inhibiting the hypothalamic-pituitary-gonadal axis, causing infertility in both men and women. These findings underscore the profound health concerns associated with alcohol-induced damage, emphasizing the need for public awareness regarding the intricate interplay between immune responses and the multi-organ impacts of alcohol consumption.

Rats Orally Administered with Ethyl Alcohol for a Prolonged Time Show Histopathology of the Epididymis and Seminal Vesicle Together with Changes in the Luminal Metabolite Composition

Prolonged ethanol (EtOH) consumption is associated with male infertility, with a decreased spermatogenesis rate as one cause. The defective maturation and development of sperm during their storage in the cauda epididymis and transit in the seminal vesicle can be another cause, possibly occurring before the drastic spermatogenesis disruption. Herein, we demonstrated that the cauda epididymis and seminal vesicle of rats, orally administered with EtOH under a regimen in which spermatogenesis was still ongoing, showed histological damage, including lesions, a decreased height of the epithelial cells and increased collagen fibers in the muscle layer, which implicated fibrosis. Lipid peroxidation (shown by malondialdehyde (MDA) levels) was observed, indicating that reactive oxygen species (ROS) were produced along with acetaldehyde during EtOH metabolism by CYP2E1. MDA, acetaldehyde and other lipid peroxidation products could further damage cellular components of the cauda epididymis and seminal vesicle, and this was supported by increased apoptosis (shown by a TUNEL assay and caspase 9/caspase 3 expression) in these two tissues of EtOH-treated rats. Consequently, the functionality of the cauda epididymis and seminal vesicle in EtOH-treated rats was impaired, as demonstrated by a decreases in 1H NMR-analyzed metabolites (e.g., carnitine, fructose), which were important for sperm development, metabolism and survival in their lumen.

Cyclosporine A induces cardiac remodeling through TGF-β/Smad3/miR-29 signaling pathway and alters gene expression of miR-30b-5p/CaMKIIδ isoforms pathways: alleviating effects of moderate exercise

BACKGROUND

Cyclosporine A (CsA)-induced cardiac interstitial fibrosis and cardiac hypertrophy are highly known phenomena; however, the basic mechanisms of CsA cardiotoxicity are unclear. The present study evaluated the role of the Transforming growth factor-beta (TGF-β)/Smad3/miR-29b signaling pathway and CaMKIIδ isoforms gene expression in cardiac remodeling under CsA exposure alone or combined with moderate exercise.

METHODS

A total of 24 male Wistar rats were divided into control, cyclosporine (30 mg/kg BW), and cyclosporine-exercise groups.

RESULTS

After 42 days of treatment, the findings revealed a significant decline in miR-29 and miR-30b-5p gene expression and an increase in gene expression of Smad3, calcium/calmodulin-dependent protein kinaseIIδ (CaMKIIδ) isoforms, Matrix Metalloproteinases (MMPs), protein expression of TGF-β, heart tissue protein carbonyl and oxidized LDL (Ox-LDL), and plasma LDL and cholesterol levels in the CsA-treated group compared to the control group. The CsA group presented greater histological heart changes such as fibrosis, necrosis, hemorrhage, infiltrated leukocyte, and left ventricular weight/heart weight than the control group. Moreover, combined moderate exercise and CsA relatively improved gene expression changes and histological alternations compared to the CsA group.

CONCLUSION

TGF-β-Smad3-miR-29 and CaMKIIδ isoforms may mainly contribute to the progression of heart fibrosis and hypertrophy due to CsA exposure, providing new insight into the pathogenesis and treatment of CsA-induced side effects on the heart tissue.

Impact of Alcohol Consumption on Male Fertility Potential: A Narrative Review

Alcohol abuse disorder is a serious condition, implicating more than 15 million people aged 12 years and older in 2019 in the United States. Ethanol (or ethyl alcohol) is mainly oxidized in the liver, resulting in the synthesis of acetaldehyde and acetate, which are toxic and carcinogenic metabolites, as well as in the generation of a reductive cellular environment. Moreover, ethanol can interact with lipids, generating fatty acid ethyl esters and phosphatidylethanol, which interfere with physiological cellular pathways. This narrative review summarizes the impact of excessive alcohol consumption on male fertility by describing its metabolism and how ethanol consumption may induce cellular damage. Furthermore, the impact of alcohol consumption on hormonal regulation, semen quality, and genetic and epigenetic regulations is discussed based on evidence from animal and human studies, focusing on the consequences on the offspring. Finally, the limitations of the current evidence are discussed. Our review highlights the association between chronic alcohol consumption and poor semen quality, mainly due to the development of oxidative stress, as well as its genotoxic impact on hormonal regulation and DNA integrity, affecting the offspring’s health. New landscapes of investigation are proposed for the identification of molecular markers for alcohol-associated infertility, with a focus on advanced OMICS-based approaches applied to the analysis of semen samples.

Ethanol consumption increases renal dysfunction and mortality in a mice model of sub-lethal sepsis

Chronic ethanol consumption and sepsis cause oxidative stress and renal dysfunction. This study aimed to examine whether chronic ethanol consumption sensitizes the mouse kidney to sub-lethal cecal ligation and puncture (SL-CLP) sepsis, leading to impairment of renal function by tissue oxidative and inflammatory damage. Male C57BL/6J mice were treated for 9 weeks with ethanol (20%, v/v) before SL-CLP was induced. Systolic blood pressure (SBP), survival rate, creatinine plasma, oxidative stress, and inflammatory parameters, inducible nitric oxide synthase (iNOS), cytokines, and metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) levels were evaluated. Chronic ethanol consumption increased SBP, plasma creatinine, O2.-, H2O2, lipid peroxidation, catalase activity, Nox4, IL-6, and TNF-α levels, and MMP-9/TIMP-1 ratio. SL-CLP decreased SBP, increased creatinine, lipid peroxidation, IL-6, TNF-α, nitrate/nitrite (NOx), and iNOS levels, and MMP-2/TIMP-2 ratio, and decreased catalase activity. SL-CLP mice previously treated with ethanol showed a similar decrease in SBP but higher mortality and creatinine levels than SL-CLP alone. These responses were mediated by increased O2-, lipid peroxidation, IL-6, TNF-α, NOx, iNOS, MMP-2, and MMP-9 levels, and MMP-9/TIMP-1 and MMP-2/TIMP-2 ratios. Our findings demonstrated that previous oxidative stress and inflammatory damage caused by ethanol consumption sensitizes the kidney to SL-CLP injury, resulting in impaired kidney function and sepsis prognosis.

Modulatory effect of tropisetron in the liver of streptozotocin-induced diabetes in rats: biochemical and histological evidence

Objectives There is an association between diabetes and liver disorders. Oxidative stress plays a crucial role in the pathology of hepatic abnormalities in diabetes. In this study, the effect of Tropisetron on the oxidative damage and histological alterations in the liver of type 1 diabetes mellitus (DM) were evaluated. Methods Thiry-five male Wistar rats were randomly divided into five experimental groups (n = 7): control (C), tropisetron (T), diabetes (D), diabetes + tropisetron (D + T) and diabetes + glibenclamide (D + G). A single injection of streptozotocin (STZ, 50 mg/kg; i.p) was used to induce diabetes. Tropisetron (3 mg/kg; i.p), as a 5-HT3 receptor antagonist and glibenclamide (1 mg/kg; i.p), as a positive control were given once daily for 2 weeks. Finally, animals were euthanized and liver samples were obtained for histopathological examination and biochemical measurements including malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx) levels. Results There is a significant increase in MDA (p < 0.001) level and a significant decrease (p < 0.001) in SOD and GPx contents in diabetic animals. Tropisetron attenuated MDA levels (p < 0.001) and enhanced SOD (p < 0.05) and GPx (p < 0.01) activities accompanied by histopathological improvement in the diabetes liver. Similar results were achieved in the rats treated with the standard drug, namely: glibenclamide. Conclusions Our findings indicate that tropisetron mitigates liver damage in the diabetes rats in part by attenuation of oxidative stress.

Tropisetron improves pancreas function and increases insulin synthesis and secretion in the STZ-induced diabetic rats: involvement of UCP2/ZnT8 pathway

OBJECTIVES

Diabetes mellitus is one of the most common metabolic diseases. Tropisetron, as a 5-HT3 receptor antagonist, has a considerable role in the inflammation and oxidative stress lowering. This study aimed to investigate the effect of this 5-HT3 receptor antagonist on insulin secretion in male diabetic rats and the possible mechanisms.

METHODS

Animals were divided into five equal groups; the control, tropisetron, diabetes, tropisetron-diabetes and glibenclamide-diabetes (7 in each group). Tropisetron and glibenclamide were administrated for 2 weeks after inducing type 1 diabetes.

KEY FINDINGS

We demonstrated that insulin secretion improved robustly in diabetes-tropisetron compared with the diabetic group. Oxidative stress biomarkers were lower in a diabetes-tropisetron group than in diabetic rats. Simultaneously, tropisetron administration promoted the expression of ZnT8 and GLUT2 and also beta-cell mass in pancreatic tissue, while the expression of uncoupling protein 2 (UCP2) was restrained. The histological evaluation confirmed our results. These effects were equipotent with glibenclamide, indicating that tropisetron can protect islets from the abnormal insulin secretion and morphological changes induced by type 1 diabetes.

CONCLUSIONS

This effect might be partly related to the modulated UCP2/ZnT8 signal pathway and improved oxidative stress-induced damage.

Oxidative Stress in Male Infertility: Causes, Effects in Assisted Reproductive Techniques, and Protective Support of Antioxidants

The spermatozoon is a highly specialized cell, whose main function is the transport of the intact male genetic material into the oocyte. During its formation and transit throughout male and female reproductive tracts, sperm cells are internally and externally surrounded by reactive oxygen species (ROS), which are produced from both endogenous and exogenous sources. While low amounts of ROS are known to be necessary for crucial physiological sperm processes, such as acrosome reaction and sperm-oocyte interaction, high levels of those species underlie misbalanced antioxidant-oxidant molecules, generating oxidative stress (OS), which is one of the most damaging factors that affect sperm function and lower male fertility potential. The present work starts by reviewing the different sources of oxidative stress that affect sperm cells, continues by summarizing the detrimental effects of OS on the male germline, and discusses previous studies addressing the consequences of these detrimental effects on natural pregnancy and assisted reproductive techniques effectiveness. The last section is focused on how antioxidants can counteract the effects of ROS and how sperm fertilizing ability may benefit from these agents.

Ethanol exposure in prenatal and early postnatal induced cardiac injury in rats: involvement of oxidative stress, Hsp70, ERK 1/2, JNK, and apoptosis in a 3-month follow-up study

Alcohol exposure during pregnancy induces a wide range of structural and functional abnormalities in the fetal heart. However, the underlying mechanism of this phenomenon is not well known. This study was undertaken to elucidate probable mechanisms of myocardial damage induced by prenatal and early postnatal ethanol treatment. Pregnant Wistar rats received ethanol 4.5 g/kg BW once per day from the seventh day of gestation (GD7) throughout lactation. The oxidative stress injury of the myocardium in pups was evaluated by measuring levels of oxidative stress biomarkers. Histopathological examinations and Western blot were performed to evaluate histological features, apoptosis, and molecular alterations in the myocardial tissue of male pups on the postnatal day 21 (PN-21) and postnatal day 90 (PN-90). The results showed that maternal ethanol consumption caused oxidative stress (impaired total antioxidant capacity and malondialdehyde), histological changes, and apoptosis of the myocardium in the pups on PN-21 and PN-90. At the molecular levels, Western blot analysis revealed that ethanol modulated the protein expression of p-ERK1/2, p-JNK, and Hsp70 in the myocardial tissue of the pups after 21 and 90 days of birth compared with the controls. These findings revealed that maternal ethanol intake induced cardiac toxicity in part, mediated by oxidative stress and apoptosis in the pups. A further mechanism study revealed that ethanol enhanced ERK1/2 and JNK phosphorylation and Hsp70 protein expression.