Role of α-tocopherol and Lactobacillus plantarum in the alleviation of mercuric chloride-induced testicular atrophy in rat's model: Implication of molecular mechanisms

Protective effects of oral administration of lactic acid bacteria strains against methylmercury-induced intestinal toxicity in a murine model

The utilization of lactic acid bacteria has been proposed to mitigate the burden of heavy metal exposure through processes probably involving chelation and reduced metal bioaccessibility. We evaluated the effects of daily intake of two strains of lactobacilli (Lactobacillus intestinalis LE1 or Lactobacillus johnsonii LE2) on intestinal toxicity during methylmercury (MeHg) exposure through drinking water (5 mg/L) for two months in mice. MeHg exposure resulted in inflammation and oxidative stress at the colon, as well as an increase in intestinal permeability accompanied by decreased fecal short-chain fatty acids (SCFA). The administration of the strains resulted in a differential protective effect that, based on their chelation capacity, supported the existence of additional mechanisms of action besides chelation. Both strains reduced IL-1β levels and oxidative stress, while LE1 lowered TNF-α, diminished MeHg-induced mucus over-secretion triggered by the IL-4/IL-13/STAT6 pathway, reduced intestinal permeability, and ameliorated inflammation and oxidative stress, probably by acting on the Keap1/Nrf2/ARE pathway. Administration of LE1 partially restored SCFA contents, which could be partly responsible for the positive effects of this strain in alleviating MeHg toxicity. These results demonstrate that lactobacilli strains can be useful tools in reducing the intestinal toxicity of MeHg, the main mercurial form conveyed by food.

Lactobacillus plantarum secretions may exert a cryoprotective effect on human sperm motility: A prospective in vitro study

BACKGROUND

Semen cryopreservation is a widely used procedure for fertility preservation, despite some level of cryodamage that may occur in spermatozoa after thawing. However, there is some evidence that lactobacilli, one of the bacteria found in semen, might benefit sperm quality.

OBJECTIVES

This study aims to determine whether the addition of Lactobacillus plantarum secretions to sperm freezing medium has an impact on sperm motility, morphology, and DNA fragmentation.

MATERIALS AND METHODS

This is a prospective auto-controlled study. It was conducted on 30 raw semen samples from 30 infertile men attending a fertility center for semen analysis. Before freezing, all the samples were analyzed for motility, morphology, and DNA fragmentation percentages. Each sample was then divided equally into three aliquots. Cryopreservation was performed on each aliquot using one of the following three media: without Lactobacillus plantarum secretions (control group) or with 107 or 108 colony-forming units/mL Lactobacillus plantarum secretions. Sperm motility, morphology, and DNA integrity were evaluated after the cryopreservation media were added and after semen thawing.

RESULTS

The results of this study indicated that after thawing, no statistically significant decrease in progressive motility and non-progressive percentages were detected in the sperm freezing medium supplemented with 108 colony-forming units/mL Lactobacillus plantarum secretions than the fresh raw semen. Moreover, multivariate linear regression model analyses showed that the progressive motility (p = 0.02), non-progressive motility (p = 0.016), and non-motile spermatozoa (p = 0.012) percentages were significantly decreased in the freezing medium (without Lactobacillus plantarum secretions) compared to the fresh raw semen.

DISCUSSION AND CONCLUSION

To the best of our knowledge, this is the first study showing that Lactobacillus plantarum secretions had a cryoprotective effect on sperm motility when added to the sperm freezing medium. Furthermore, Lactobacillus plantarum secretions were found to protect sperm DNA integrity more effectively than the freezing medium without Lactobacillus plantarum secretions in non-normozoospermia group. Cryopreservation procedures must therefore be optimized to minimize any iatrogenically induced sperm DNA damage, given the correlation between sperm DNA damage and increased mutation loads in progeny.

Amelioration of mercuric chloride-induced physiologic and histopathologic alterations in rats using vitamin E and zinc chloride supplement

The drastic effects of mercuric chloride and the protective efficiency of vitamin E and zinc chloride co-supplementation were clearly investigated in this study. Male rats were divided into four groups. The first was the control. The second received vitamin E (100 mg/kg) and zinc chloride (30 mg/kg) daily. In comparison, the third received mercuric chloride (1 mg/kg) daily, and the fourth received the same mercuric chloride dose supplemented with the same vitamin E and zinc chloride doses. Mercury promotes a significant decline in body weight. It causes a considerable reduction in total red blood cells (RBCs) count and hemoglobin concentration; however, white blood cells (WBCs) increased significantly. Significant mercury-induced elevations in hepatic and renal functions were observed. Mercury induced substantial reductions in catalase (CAT) and superoxide dismutase (SOD). Mercury caused apoptotic DNA fragmentation. It induced degeneration and necrosis in the liver and kidney. It induced necrosis, leukocyte infiltration and blood vessel congestion in the cerebral cortex. Shrinkage and deterioration of Purkinje cells of the cerebellum were observed in response to mercuric chloride toxicity. Mercuric chloride enhanced shrinking in seminiferous tubules and Leydig cells. It reduced sperm count, sperm motility, and testosterone concentration; however, it promoted abnormal sperm morphology. Administration of vitamin E and zinc chloride showed marked improvement in different parameters under investigation, however, further research is needed to determine fate of mercury.

Cross-Regulation between Autophagy and Apoptosis Induced by Vitamin E and Lactobacillus Plantarum through Beclin-1 Network

Autophagy and apoptosis are two important regulatory mechanisms for how the body can respond to diseases. This study was designed to investigate the protective actions of vitamin E (Vit-E) and lactobacillus plantarum (Lac-B) against mercuric chloride (HgCl₂)-induced kidney injury. Thirty albino rats were divided into five groups: group 1 served as the normal group; rats in group 2 received high doses of HgCl₂; rats in groups 3, 4 and 5 were given Vit-E, Lac-B and the combination of Vit-E and Lac-B, respectively along with HgCl₂ for two weeks. HgCl₂ provoked renal injury, manifested by elevation in serum urea, urea nitrogen and creatinine. Kidney levels of oxidative stress and inflammation were markedly increased post HgCl₂ administration. Moreover, HgCl₂ significantly elevated the gene expression levels of VCAM-1 and cystatin C, while podocin was downregulated. Additionally, it markedly decreased the protein expression of Beclin-1 and Bcl-2. Histopathological examination revealed massive degeneration with congested blood vessels following HgCl₂ administration. Treatment with Vit-E or/and Lac-B restored the normal levels of the previously mentioned parameters, as well as improved the morphology of kidney tissues. Both Vit-E and Lac-B provided a protective effect against HgCl₂-induced kidney damage by regulating autophagy and apoptosis.

Vitamin E and Lactobacillus Provide Protective Effects Against Liver Injury Induced by HgCl2: Role of CHOP, GPR87, and mTOR Proteins

BACKGROUND AND OBJECTIVE

Mercury is one of the most harmful heavy metals and its toxicity causes severe multi-organ dysfunction. This study was designed to explore novel molecular pathways involved in the hepatoprotective effect of vitamin E (Vit-E) and Lactobacillius plantarum (Lac-B) against mercury toxicity.

METHOD

Acute hepatotoxicity was induced by administration of high dose of mercuric chloride (HgCl2) in male rats, Vit-E or/and Lac-B were given along with HgCl2 for 2 weeks. The effects of those antioxidants were studied focusing on their anti-apoptotic, anti-oxidative stress and anti-inflammatory eficacies. Histopathological examinations were also conducted.

RESULTS

The administration of HgCl2 induced liver injury which manifested by elevation in serum ALT and AST. Liver MDA, caspase-3 and TNF-α levels were markedly increased; whereas, GSH level and SOD activity were declined. HgCl2 significantly elevated the expressions of hepatic CHOP, GPR87, NF-κB and mTOR. Histopathological examination revealed massive hepatocyte degeneration following HgCl2 administration. Treatment with Vit-E or/and Lac-B restored the normal levels of the previously mentioned parameters, as well as improved hepatic architecture.

CONCLUSION

Vit-E and Lac-B provided protective effect against HgCl2-induced hepatotoxicity via reduction of oxidative stress and inflammation, and downregulation of CHOP, GPR87, NF-κB and mTOR proteins' expressions.

Counteracting effects of heavy metals and antioxidants on male fertility

Infertility is regarded as a global health problem affecting 8-12% of couples. Male factors are regarded as the main cause of infertility in 40% of infertile couples and contribute to this condition in combination with female factors in another 20% of cases. Abnormal sperm parameters such as oligospermia, asthenospermia, and teratozoospermia result in male factor infertility. Several studies have shown the deteriorative impact of heavy metals on sperm parameters and fertility in human subjects or animal models. Other studies have pointed to the role of antioxidants in counteracting the detrimental effects of heavy metals. In the currents study, we summarize the main outcomes of studies that assessed the counteracting impacts of heavy metal and antioxidants on male fertility. Based on the provided data from animal studies, it seems rational to administrate appropriate antioxidants in persons who suffer from abnormal sperm parameters and infertility due to exposure to toxic elements. Yet, further human studies are needed to approve the beneficial effects of these antioxidants.

Leaf ethanolic extract of Etlingera hemesphaerica Blume mitigates defects in fetal anatomy and endochondral ossification due to mercuric chloride during the post-implantation period in Mus musculus

This study aimed to investigate the effectiveness of leaf ethanolic extract of Etlingera hemisphaerica (LE3H) in reducing defects in fetal anatomy and endochondral ossification in mice induced by HgCl₂ during the post-implantation period. Pregnant mice were divided into four groups, each consisting of 10 dams, and received drink and food ad libitum. The first group was administered LE3H (E1), the second one HgCl₂ (E2), the third one HgCl₂+LE3H (E3), and the fourth was control (E0), administered double-distilled water only. HgCl₂ (5 mg/kg bw) was administrated by injection intraperitoneally on gestation day (GD)9 and LE3H (0.39 mg/g bw) was administered by gavage on GD10. The treated and control animals were killed by cervical dislocation on GD18, dissected, and the morphologically normal living fetuses (MNLF) were collected. The MNLF of E0, E1, E2, and E3 from 5 dams were fixed with Bouin solution, and observed using the free hand razor blade technique for soft tissue examination. The remaining MNLF were fixed with 96% ethanol, and then stained with Alizarin Red S and Alcian Blue for ossification examination. Index of length of ossified part (ILOP) of humerus, index of width of ossified part (IWOP) of humerus, ILOP of femur, and IWOP of femur were calculated. E2 had higher cases of anatomical defects (74,6%) than E3 (48.9%), E1 (15.0%), and E0 (0%). E2 had humerus IWOP of 0.82±0.03, which was significantly lower than that of E0 (0.89±0.04) and E1 (0.89±0.03), while that of E1 and E0 was not significantly different from each other. Meanwhile, IWOP in E3 (0.88±0.03) was significantly higher than that in E2, but not different from that in E1 and E0. Thus, LE3H mitigated defects in fetal anatomy and endochondral ossification induced by HgCl₂ in mice.

Exogenous Factors Affecting the Functional Integrity of Male Reproduction

Natural processes along with increased industrial production and the irresponsible behavior of mankind have resulted in environmental pollution. Environmental pollutants can be categorized based on their characteristics and appearance into the following groups: physical, biological, and chemical. Every single one of them represents a serious threat to the male reproductive tract despite the different modes of action. Male gonads and gametes are especially vulnerable to the effect of exogenous factors; therefore, they are considered a reliable indicator of environmental pollution. The impact of xenobiotics or radiation leads to an irreversible impairment of fertility displayed by histological changes, modulated androgen production, or compromised spermatozoa (or germ cells) quality. The present article reviews the exogenous threats, male reproductive system, the mode of action, and overall impact on the reproductive health of humans and animals.

Effects of Cadmium, Lead, and Mercury on the Structure and Function of Reproductive Organs

Reproductive organs are essential not only for the life of an individual but also for the survival and development of the species. The response of reproductive organs to toxic substances differs from that of other target organs, and they may serve as an ideal “barometer” for the deleterious effects of environmental pollution on animal and human health. The incidence of infertility, cancers, and associated maladies has increased in the last fifty years or more, while various anthropogenic activities have released into the environment numerous toxic substances, including cadmium, lead, and mercury. Data from epidemiological studies suggested that environmental exposure to cadmium, lead, and mercury may have produced reproductive and developmental toxicity. The present review focused on experimental studies using rats, mice, avian, and rabbits to demonstrate unambiguously effects of cadmium, lead, or mercury on the structure and function of reproductive organs. In addition, relevant human studies are discussed. The experimental studies reviewed have indicated that the testis and ovary are particularly sensitive to cadmium, lead, and mercury because these organs are distinguished by an intense cellular activity, where vital processes of spermatogenesis, oogenesis, and folliculogenesis occur. In ovaries, manifestation of toxicity induced by cadmium, lead, or mercury included decreased follicular growth, occurrence of follicular atresia, degeneration of the corpus luteum, and alterations in cycle. In testes, toxic effects following exposure to cadmium, lead, or mercury included alterations of seminiferous tubules, testicular stroma, and decrease of spermatozoa count, motility and viability, and aberrant spermatozoa morphology.