Protective effect of hemin against cadmium-induced testicular damage in rats

Cumulus Cell Transcriptome after Cumulus-Oocyte Complex Exposure to Nanomolar Cadmium in an In Vitro Animal Model of Prepubertal and Adult Age

Cadmium (Cd), a highly toxic pollutant, impairs oocyte fertilization, through oxidative damage on cumulus cells (CCs). This study analysed the transcriptomic profile of CCs of cumulus-oocyte complexes (COCs) from adult and prepubertal sheep, exposed to Cd nanomolar concentration during in vitro maturation. In both age-groups, CCs of matured oocytes underwent RNA-seq, data analysis and validation. Differentially expressed genes (DEGs) were identified in adult (n = 99 DEGs) and prepubertal (n = 18 DEGs) CCs upon Cd exposure. Transcriptomes of adult CCs clustered separately between Cd-exposed and control samples, whereas prepubertal ones did not as observed by Principal Component Analysis. The transcriptomic signature of Cd-induced CC toxicity was identified by gene annotation and literature search. Genes associated with previous studies on ovarian functions and/or Cd effects were confirmed and new genes were identified, thus implementing the knowledge on their involvement in such processes. Enrichment and validation analysis showed that, in adult CCs, Cd acted as endocrine disruptor on DEGs involved in hormone biosynthesis, cumulus expansion, regulation of cell signalling, growth and differentiation and oocyte maturation, whereas in prepubertal CCs, Cd affected DEGs involved in CC development and viability and CC-oocyte communications. In conclusion, these DEGs could be used as valuable non-invasive biomarkers for oocyte competence.

Impacts of cadmium on male fertility: Lessons learnt so far

Cadmium (Cd) is one of the most dangerous heavy metals in the world. Globally, toxicities associated with cadmium and its attendant negative impact on humans and animals cannot be under-estimated. Cd is a heavy metal, and people are exposed to it through contaminated foods and smoking. Cd exerts its deleterious impacts on the testes (male reproductive system) by inducing oxidative stress, spermatogenic cells apoptosis, testicular inflammation, decreasing androgenic and sperm cell functions, disrupting ionic homeostasis, pathways and epigenetic gene regulation, damaging vascular endothelium and blood testes barrier. In association with other industrial by-products, Cd has been incriminated for the recent decline of male fertility rate seen in both man and animals. Understanding the processes involved in Cd-induced testicular toxicity is vital for the innovation of techniques that will help ameliorate infertility in males. In this review, we summed up recent studies on the processes of testicular toxicity and male infertility due to Cd exposure. Also, the usage of different compounds including phytochemicals, and plant extracts to manage Cd reprotoxicity will be reviewed.

Etanercept Mitigates Cadmium Chloride-induced Testicular Damage in Rats "An Insight into Autophagy, Apoptosis, Oxidative Stress and Inflammation"

RATIONALE

Cadmium (Cd) is an environmental and occupational toxin that represents a serious health hazard to humans and other animals. One of the negative consequences of cadmium exposure is testicular injury.

OBJECTIVE

This study aimed to investigate the therapeutic effect of etanercept against cadmium chloride-induced testicular damage and the probable underlying mechanisms of its action.

METHODS

A total of sixty rats were divided into six groups: control, cadmium chloride (CdCl₂) (7 mg/ kg i.p.), and CdCl₂ treated with etanercept (5,10 and 15 mg/kg s.c.) and etanercept only (15 mg/kg s.c.). CdCl₂ was administrated as a single dose, while etanercept was administered every 3 days for 3 weeks.

RESULTS

CdCl₂ reduced serum testosterone, testicular glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD). However, it elevated the levels of malondialdehyde (MDA) and microtubule-associated protein light chain 3B (LC3B) in the testes. Cadmium caused pathogenic alterations as well as increased levels of inflammatory biomarkers such as tumor necrosis factor-alpha (TNF-α) and nuclear factor-kappa B (NF-κB). Besides, the gene expressions of caspase-3 and inducible nitric oxide synthase (i-NOS) and Beclin-1 protein increased with CdCl₂ exposure. Interestingly, etanercept relieved the previous toxic effects induced by CdCl₂ in a dose-dependent manner as evidenced by inhibition of oxidative stress, inflammatory markers, Beclin-1, LC3B, and caspase-3 accompanied by improvement in histopathological changes.

CONCLUSION

Etanercept provides a potential therapeutic approach to treat testicular tissue against the damaging effects of Cd by reducing oxidative stress, inflammation, apoptosis, and autophagy.

Nutraceuticals: A New Challenge against Cadmium-Induced Testicular Injury

Cadmium (Cd) is a widespread heavy metal and a ubiquitous environmental toxicant. For the general population, the principal causes of Cd exposure are cigarette smoking, air pollution and contaminated water and food consumption, whereas occupational exposure usually involves humans working in mines or manufacturing batteries and pigments that utilize Cd. The aim of the present review is to evaluate recent data regarding the mechanisms of Cd-induced testicular structural and functional damages and the state of the art of the therapeutic approaches. Additionally, as the current literature demonstrates convincing associations between diet, food components and men's sexual health, a coherent nutraceutical supplementation may be a new valid therapeutic strategy for both the prevention and alleviation of Cd-induced testicular injury. The toxic effects on testes induced by Cd include many specific mechanisms, such as oxidative stress, inflammation and apoptosis. As no specific therapy for the prevention or treatment of the morbidity and mortality associated with Cd exposure is available, the development of new therapeutic agents is requested. Dietary strategies and the use of nutraceuticals, particularly abundant in fresh fruits, beans, vegetables and grains, typical of the Mediterranean diet, are recommended against Cd-induced testicular injury.

Effects of the methanol root extract of Carpolobia lutea on sperm indices, acrosome reaction, and sperm DNA integrity in cadmium-induced reproductive toxicity in male Wistar rats

OBJECTIVE

Oxidative stress is a mechanism of cadmium-induced reproductive dysfunction. Carpolobia lutea is a free radical scavenger. Our study investigated the potential protective effects of Carpolobia lutea root methanol extract against cadmium-induced reproductive toxicity.

METHODS

We obtained the Carpolobia lutea root in Akure, and it was authenticated at the Forestry Research Institute of Nigeria (FRIN) herbarium, Ibadan, Nigeria, with FHI number 109784. We used Soxhlet extraction to obtain its methanol extract. We used thirty male Wistar rats (150-170g) in this study, (n=5 per group), and treated them as follows: Control (1 ml/kg normal saline), Cd (2 mg/kg), Cd+MCL (2 mg/kg+100 mg/kg), Cd+MCL (2 mg/kg+200 mg/kg), MCL (100 mg/kg), MCL (200 mg/kg). We administered Carpolobia lutea orally for 8 weeks. We administered a single dose of 2 mg/kg of cadmium intraperitoneally. We assessed the sperm profile using a computer-aided sperm analyzer. Under microscopy, we determined the sperm acrosome reaction and the DNA damage. We measured the seminal fructose level using spectrophotometry, and the data were analyzed using ANOVA at p<0.05.

RESULTS

Cd+MCL (2mg/kg+200 mg/kg) significantly increased sperm count (339.0±25.0 vs. 29.0±4.5 million/mL), motility (80.0±0.2 vs. 55.0±4.9%), viability (68.7±2.7 vs. 31.3±2.9%) and decreased abnormal sperm (28.3±1.7 vs. 43.3±2.5%), relative to the cadmium group. Cd+MCL (2mg/kg+200 mg/kg) significantly increased acrosome reaction (68.0±7.5 vs. 15.2±2.4%) and seminal fructose level (0.49±0.06 vs. 0.28±0.06 mmol/L) relative to the cadmium group. Cd+MCL (2mg/kg+200 mg/kg) significantly decreased sperm DNA damage (14.1±1.6 vs. 35.9±5.3%) in relation to the cadmium group.

CONCLUSIONS

Carpolobia lutea root extract improves the sperm variables of rats exposed to cadmium.

Tadalafil alleviates cisplatin-induced reproductive toxicity through the activation of the Nrf2/HO-1 pathway and the inhibition of oxidative stress and apoptosis in male rats

Male reproductive toxicity is a well-known adverse effect of cisplatin (CIS), an important antineoplastic agent used to control several types of cancers. Tadalafil (TDF), is a long-acting phosphodiesterase-5 (PDE5) inhibitor commonly used as treatment for erectile dysfunction. The aim of this work was to study the possible protective effect of TDF against CIS-induced testicular toxicity in rats and the possible involvement of Nrf2/HO-1 pathway, which demonstrates antioxidant and inflammatory activities utilizing zinc protoporphyrin-IX (ZnPP) as HO-1 inhibitor. Results revealed that TDF attenuated the CIS-induced disturbances in sperm count and activities, normalized the serum testosterone level, improved the CIS-induced changes in epididymal and testicular weights and restored the normal structure of testicular tissues. In addition, TDF upregulated the gene expression levels of Nrf2 and HO-1 and the activity of HO-1 whereas, it reduced the CIS-induced changes in testicular oxidative stress markers and the levels of inflammatory mediators (TNF-α and iNOS). Furthermore, TDF antagonized the CIS-induced increase in testicular gene expression of apoptotic markers caspase-3 and Bax, and the decrease in Bcl-2. However, ZnPP co-administration significantly attenuated all TDF-mediated improvements in CIS-induced testicular toxicity, biochemical changes, and apoptosis. In conclusion, TDF exerts a protective effect against CIS-induced reproductive toxicity in males, through different mechanisms, besides its inhibitory action to PDE5, possibly mediated by the upregulation of Nrf2/HO-1, along with its antioxidant, anti-inflammatory, and anti-apoptotic effects. Hence, the use of TDF represents a promising therapeutic approach to protect the male reproductive system from the harmful toxic effects of CIS.

Infliximab abrogates cadmium-induced testicular damage and spermiotoxicity via enhancement of steroidogenesis and suppression of inflammation and apoptosis mediators

Cadmium(Cd) is a serious environmental and occupational contaminant that represents a serious health hazard to humans and other animals. Reproductive health problems have been reported in men exposed to Cd. Testicular damage is one of the deleterious effects due to Cd exposure. Cd-induced testicular toxicity is mediated through oxidative stress, inflammation, testosterone inhibition and apoptosis. Thus, the present study was performed to assess the possible protective role of infliximab (IFX), anti-TNFα agent, against Cd-induced testicular damage and spermiotoxicity in rats. The rats were randomly allotted into six experimental groups: control, Cd sulphate treated, Cd sulphate treated with infliximab (5 mg/kg), Cd sulphate with infliximab (7 mg/kg), infliximab alone (5 mg/kg), and infliximab alone (7 mg/kg). The control group received saline. To induce testicular damage, Cd sulphate (1.5 mg/100 gm body weight/day) was dissolved in normal saline and orally administrated for 3 consecutive weeks. The rats in infliximab-treated groups were given a weekly dose of 5 mg/kg/week or 7 mg/kg/week of infliximab intraperitoneally. In the current study Cd exposure reduced sperm count, markers of testicular function, sperm motility as well as gene expression of testicular 3β-HSD and 17β-HSD and serum testosterone level. Additionally, it increased testicular oxidative stress, inflammatory and apoptotic markers. The histopathologic studies supported the biochemical findings. Treatment with infliximab significantly attenuated Cd-induced injury verified by the restoration of testicular architecture, enhancement of steroidogenesis, preservation of spermatogenesis, modulation of the inflammatory reaction along with suppression of oxidative stress and apoptosis. It was concluded that infliximab, through its antioxidant, anti-inflammatory and anti-apoptotic effects, represents a potential therapeutic option to protect the testicular tissue from the detrimental effects of Cd.

Selenium alleviates cadmium-induced inflammation and meat quality degradation via antioxidant and anti-inflammation in chicken breast muscles

Cadmium (Cd) as a widespread toxic heavy metal accumulates in animal food including chicken meat through food chain enrichment and finally threatens human health. Selenium (Se) is an essential mineral and possesses antagonistic effects on Cd-induced multiple organs' toxicity in chickens. The objective of the present study was to reveal the antagonistic mechanisms of Se to Cd from the aspects of oxidative stress, inflammation, and meat quality in chicken breast muscles. Firstly, the results showed that Cd significantly elevated the levels of malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and protein carbonyl, and declined the levels of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) to trigger oxidative stress in chicken breast muscles. However, Se treatment significantly alleviated Cd-induced oxidative stress by increasing the levels of GSH-Px, SOD, and CAT, and decreasing the levels of MDA, H₂O₂, and protein carbonyl. Secondly, Se obviously inhibited the expressions of Cd-activated inflammation-related genes including tumor necrosis factor (TNF-α), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), inducible nitric oxide synthase (iNOS), prostaglandin-endoperoxide synthase 2 (COX-2), and prostaglandin E synthase (PTGEs) in chicken breast muscles. Thirdly, meat quality-related parameters including pH_45min, ultimate pH (pHu), and drip loss were also detected, and the results showed that Se markedly recovered Cd-induced dropt of pH_45min and increase of drip loss in chicken breast muscles. In brief, these findings demonstrated that Se significantly alleviated Cd-induced oxidative stress and inflammation, and declined meat quality of chicken breast muscles.

Ameliorative Effects of Selenium on Cadmium-Induced Injury in the Chicken Ovary: Mechanisms of Oxidative Stress and Endoplasmic Reticulum Stress in Cadmium-Induced Apoptosis

Despite the well-established toxicity of cadmium (Cd) to animals and the ameliorative effects of selenium (Se), some specific mechanisms in the chicken ovary are not yet clarified. To explore the mechanism by which the toxicity effect of Cd is induced and explore the effect of supranutritional Se on Cd toxicity in female bird reproduction, forty-eight 50-day-old Isa Brown female chickens were divided randomly into four groups. Group I (control group) was fed the basic diet containing 0.2 mg/kg Se. Group II (Se-treated group) was fed the basic diet supplemented with sodium selenite (Na₂SeO₃), and the total Se content was 2 mg/kg. Group III (Se + Cd-treated group) was fed the basic diet supplemented with Na₂SeO₃; the total Se content was 2 mg/kg, and it was supplemented with 150 mg/kg cadmium chloride (CdCl₂). Group IV (Cd-treated group) was with the basic diet supplemented with 150 mg/kg CdCl₂. The Cd, estradiol (E2), and progestogen (P4) contents changed after subchronic Cd exposure in chicken ovarian tissue; subsequently, oxidative stress occurred and activated the endoplasmic reticulum (ER) pathway to induce apoptosis. Further, Se decreased the accumulation of Cd in ovarian tissue, increased the E2 and P4 contents, alleviated oxidative stress, and reduced apoptosis via the ER stress pathway. The present results demonstrated that Cd could induce apoptosis via the ER stress pathway in chicken ovarian tissue and that Se had a significant antagonistic effect. These results are potentially valuable for finding a strategy to prevent Cd poisoning.

Effect of hemin, baicalein and heme oxygenase-1 (HO-1) enzyme activity inhibitors on Cd-induced accumulation of HO-1, HSPs and aggresome-like structures in Xenopus kidney epithelial cells

Cadmium is a highly toxic environmental pollutant that can cause many adverse effects including cancer, neurological disease and kidney damage. Aquatic amphibians are particularly susceptible to this toxicant as it was shown to cause developmental abnormalities and genotoxic effects. In mammalian cells, the accumulation of heme oxygenase-1 (HO-1), which catalyzes the breakdown of heme into CO, free iron and biliverdin, was reported to protect cells against potentially lethal concentrations of CdCl₂. In the present study, CdCl₂ treatment of A6 kidney epithelial cells, derived from the frog, Xenopus laevis, induced the accumulation of HO-1, heat shock protein 70 (HSP70) and HSP30 as well as an increase in the production of aggregated protein and aggresome-like structures. Treatment of cells with inhibitors of HO-1 enzyme activity, tin protoporphyrin (SnPP) and zinc protoporphyrin (ZnPP), enhanced CdCl₂-induced actin cytoskeletal disorganization and the accumulation of HO-1, HSP70, aggregated protein and aggresome-like structures. Treatment of cells with hemin and baicalein, which were previously shown to provide cytoprotection against various stresses, induced HO-1 accumulation in a concentration-dependent manner. Also, treatment of cells with hemin and baicalein suppressed CdCl₂-induced actin dysregulation and the accumulation of aggregated protein and aggresome-like structures. This cytoprotective effect was inhibited by SnPP. These results suggest that HO-1-mediated protection against CdCl₂ toxicity includes the maintenance of actin cytoskeletal and microtubular structure and the suppression of aggregated protein and aggresome-like structures.

Histopathological Effects of Titanium Dioxide Nanoparticles and The Possible Protective Role of N-Acetylcysteine on The Testes of Male Albino Rats

BACKGROUND

Titanium dioxide (TiO₂) is a white pigment which is used in paints, plastics, etc. It is reported that TiO₂ induces oxidative stress and DNA damage. N-acetylcysteine (NAC) has been used to fight oxidative stress-induced damage in different tissues. The objective of this study was to evaluate the toxic effects of orally administered TiO₂ nanoparticles and the possible protective effect of NAC on the testes of adult male albino rats.

MATERIALS AND METHODS

In this experimental study, 50 adult male albino rats were classified into five groups. Group I was the negative control, group II was treated with gum acacia solution , group III was treated with NAC, group IV was treated with TiO₂ nanoparticles, and group V was treated with 100 mg/kg of NAC and 1200 mg/kg TiO₂ nanoparticles. Total testosterone, glutathione (GSH), and serum malondialdehyde (MDA) levels were estimated. The testes were subjected to histopathological, electron microscopic examinations, and immunohistochemical detection for tumor necrosis factor (TNF)-α. Cells from the left testis were examined to detect the degree of DNA impairment by using the comet assay.

RESULTS

TiO₂ nanoparticles induced histopathological and ultrastructure changes in the testes as well as positive TNF-α immunoreaction in the testicular tissue. Moreover, there was an increase in serum MDA while a decrease in testosterone and GSH levels in TiO₂ nanoparticles-treated group. TiO₂ resulted in DNA damage. Administration of NAC to TiO₂- treated rats led to improvement of the previous parameters with modest protective effects against DNA damage.

CONCLUSION

TiO₂-induced damage to the testes was mediated by oxidative stress. Notably, administration of NAC protected against TiO₂'s damaging effects.

Synergistic Effects of Heavy Metals and Pesticides in Living Systems

There is a widespread repeated exposure of the population to the pesticides and heavy metals of occupational and environmental origin. Such population is forced to undergo continuous stress imposed by combined exposure of the heavy metals and different classes of the pesticides used in agricultural as well as health practices. The existing reports from several workers have indicated that heavy metals and pesticides in combination may lead more severe impact on the human health when compared to their individual effects. Such a combination of pesticides and heavy metals may also change or influence the detection of exposure. Several studies in past have shown the synergistic toxic effects of heavy metals and pesticides. Such evaluations have revealed the synergistic interactions of various heavy metals and pesticides in animals as well as humans. The aim of the present article is to provide a synthesis of existing knowledge on the synergistic effects of heavy metal and pesticides in living systems. The information included in this article may be useful for different environment protection agencies and policy makers to consider the combined effects of heavy metals and pesticides on humans while designing strategies toward environmental protection and safety regulations about human health.

Effects of Arctium lappa on Cadmium-Induced Damage to the Testis and Epididymis of Adult Wistar Rats

The protective role of Arctium lappa (AL) on the testes of rats acutely exposed to cadmium (Cd) was tested. The rats were randomly divided into a control group (C-group) and three major experimental groups, which were further subdivided into minor groups (n = 6) according to the experimental period (7 or 56 days). The C-group was subdivided into C-7 and C-56 [receiving a single saline solution, intraperitoneal (i.p.), on the first day]; the AL-group, AL-7, and AL-56, received AL extract (300 mg/kg/daily); the Cd group, Cd-7 and Cd-56, received a single i.p. dose of CdCl2 (1.2 mg/kg body weight (BW)) on the first day; the CdAL group, CdAL-7 and CdAL-56, received the same Cd dose, followed by AL extract. Water or AL extract was administered daily by gavage. After either 7 or 56 days, the testis and accessory glands were removed after whole-body perfusion. Exposure to Cd and CdAL decreased the weight of the testis and epididymis, the gonadosomatic index, seminiferous tubular (ST) diameter, and ST volumetric proportion, and increased the volumetric proportion of interstitium after 56 days. In the epididymis caput, the tubular volumetric proportion decreased along with an increase of interstitial volumetric proportion and epithelium height after 56 days. The alterations observed were less severe only after 7 days. A progressive testicular damage resulted mainly in tubules lined only by Sertoli cells. The sperm number and cell debris decreased in the epididymis. We demonstrated that the testicular damage induced by single acute i.p. exposure to Cd occurred despite the daily oral intake of AL extract.

Efficacy of Crocus sativus L. on reduction of cadmium-induced toxicity on spermatogenesis in adult rats

Cadmium is a toxic heavy metal element, which probably cause infertility by impairment in spermatogenesis. The present work aimed (i) to study the toxic effect of cadmium on spermatogenesis in rat, as well as (ii) the protective effect of Crocus sativus L. on cadmium-intoxicated rats. Cadmium chloride was administered intraperitoneally during 16 days at intervals of 48 h between subsequent treatments. Crocus sativus L. was pre-treated in both of control and cadmium-injected rats. Animals were sacrificed on day 17 after the first treatment. The left cauda epididymis was removed and immediately immersed into Hank's balanced salt solution for the evaluation of sperm count and viability, and left testis was fixed in 10% formalin for histological evaluation. Following contamination with cadmium, a decrease was observed in the number and viability of cauda epididymis sperm, which were increased by Crocus sativus L. pre-treatment (P < 0.05). In addition, cadmium decreased both cell proliferation and Johnsen Scores in the seminiferous tubules, which were reversed by Crocus sativus pre-treatment (P < 0.05). Furthermore, cadmium-induced decrease in the amount of free serum testosterone as well as an increase in lipid peroxidation activity in the testicular tissue was reversed by Crocus sativus L. (P < 0.05). These findings may support the concept that Crocus sativus L. can improve the cadmium toxicity on spermatogenesis.

The Protective Effects of Melatonin Against Oxidative Stress and Inflammation Induced by Acute Cadmium Exposure in Mice Testis

Cadmium (Cd) is widely used in daily life and was recently recognized as a possible source of human toxicity due to its ability to accumulate in organs. Previous studies have shown that Cd exposure may cause testicular toxicity through oxidative stress and an inflammatory effect. Melatonin has been demonstrated to be an effective anti-oxidant and has an anti-inflammatory effect. The aim of the present study was to investigate the toxicological effects of Cd on reproduction in male mice and the potential protective action of melatonin against these adverse effects. Adult male mice were injected intraperitoneally with Cd at a dose of 2 mg/kg body weight per day for seven consecutive days with or without melatonin pretreatment. Sex organ weight, sperm parameters including sperm quality, apoptosis, acrosome integrity, mitochondrial membrane potential, testicular morphology, serum sex hormone, inflammatory status, and oxidative stress were evaluated. The results showed that significant adverse effects were observed in the male reproductive system after Cd exposure, including alterations in sperm parameters, increased DNA damage, and sex hormone disturbance. Acute Cd exposure also significantly increased malondialdehyde (MDA) contents, decreased glutathione (GSH) and superoxide dismutase (SOD) activities, and upregulated levels of the pro-inflammatory cytokines, tumor necrosis factor-alpha (TNF-α), and interleukin-1beta (IL-1β), in the testis. In contrast, melatonin pretreatment significantly alleviated these toxic effects, and its mechanism may involve inhibiting MDA level, restoring GSH and SOD activities, and reducing the upregulation of TNF-α and IL-1β. Our data suggest that oxidative stress and inflammation are involved in Cd-induced toxicity in the male reproductive system and that co-administration of melatonin exerts a protective effect against Cd-induced male reproductive toxicity.

Effects of subchronic exposure to cadmium and diazinon on testis and epididymis in rats

The present study aimed to elucidate the structural changes in testis and epididymis of adult rats following subchronic peroral administration of cadmium at 30 mg/L, diazinon at 40 mg/L, cadmium at 30 mg/L, and diazinon at 40 mg/L, respectively. At the end of 90-day experiment, the samples of the testes and epididymis were assayed by qualitative and quantitative histological methods. The testis and epididymis weights increased following exposure to cadmium and simultaneous exposure to cadmium and diazinon. Testicular damage following cadmium and diazinon coexposure was significantly less expressive than in groups with individual administration of these compounds. Cadmium caused a significant thickening of seminiferous epithelium, cellular degeneration, and necrosis. Desquamation of immature germ cells resulted in a significant increase of intraepithelial spaces and reduced tubule volume in all experimental groups. Vascular dilation and congestion were detected in the interstitial tissue. The changes in epididymal histology in the group exposed to cadmium and group exposed simultaneously included a reduction of epithelium, necrotic epithelial cells, vasoconstriction, and interstitial edema together with mononuclear cell infiltration. Results did not indicate a synergistic or any additional effect from the simultaneous administration of both toxicants. Further research is needed to determine the significance and the mechanism of the adverse effects.

Hemin attenuates cisplatin-induced acute renal injury in male rats

Background. The aim of this study is to investigate the protective effects of hemin (the heme oxygenase-1 [OH-1] inducer) against nephrotoxic effects induced by cisplatin [cis-diamminedichloroplatinum II (CP)] in male rats. Methods. The evaluation was performed through monitoring renal redox parameters: lipid peroxidation (LPO), glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione reductase (GR), and reduced glutathione (GSH). The work also examined renal function tests (urea and creatinine), tissue proinflammatory mediator like nitric oxide (NO), and kidney cytopathology. Results. A single intraperitoneal dose of CP (10 mg/kg b.w.) caused significant elevation of blood urea, serum creatinine, and renal LPO and NO, along with significant decline of the activities of GPx and GR, but renal SOD activity and GSH level were statistically insignificant as compared to control group. Subcutaneous injection of hemin (40 µmol/kg b.w.) partially ameliorated CP-induced renal damage, based on suppression of blood urea, serum creatinine, the renal MDA and NO levels, and increased antioxidant capacity in CP-treated rats. The results of histopathological and ultrastructural investigations supported the renoprotective effect of hemin against CP-induced acute toxicity. Conclusion. The induction of HO-1 by hemin is a promising approach in the treatment of CP-induced nephrotoxicity. However, further preclinical studies are warranted to test effectiveness of CP/hemin on the outcome of tumor chemotherapy.

Simvastatin treatment ameliorates injury of rat testes induced by cadmium toxicity

Cadmium-induced testicular toxicity is mediated through oxidative stress and inflammation which eventually lead to cell death. Simvastatin, the antihyperlipidemic agent, exhibits additional antioxidant and anti-inflammatory activities. The aim of the present work was to investigate the protective effect of simvastatin against cadmium-induced testicular toxicity in rats. The rats received a single intraperitoneal (i.p.) injection of cadmium chloride (2 mg/kg). Simvastatin treatment (5 mg/kg/day, i.p.) was applied for three consecutive days, starting 1 day before cadmium administration. Cadmium significantly decreased serum testosterone, and testicular reduced glutathione and catalase activity, and significantly increased testicular malondialdehyde, nitric oxide, and cadmium ion levels. Simvastatin significantly ameliorated the biochemical changes induced by cadmium. Cadmium-induced testicular tissue injury observed by histopathological examination was attenuated by simvastatin. In addition, simvastatin significantly decreased the expression of inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor-α, nuclear factor-κB, and caspase-3, and increased heme oxygenase-1 expression in testicular tissue of rats exposed to cadmium toxicity. It was concluded that simvastatin, through its antioxidant and anti-inflammatory activities, provided a significant protective effect against cadmium-induced testicular toxicity in rats. However, starting treatment with simvastatin before cadmium exposure, as done in the present work, is not clinically applicable. Therefore, other investigations are needed to assess the protective effect of simvastatin treatment following induction of cadmium testicular toxicity.

Grape juice concentrate protects reproductive parameters of male rats against cadmium-induced damage: a chronic assay

The aim of the present study was to investigate the effects of long-term grape juice concentrate (GJC) consumption, in two dosages, on the reproductive parameters of cadmium-exposed male rats. The effects of the concentrate on body mass gain, plasma testosterone levels, reproductive organ weights, daily sperm production, sperm morphology, testis histopathological and histomorphometrical parameters, and testicular antioxidant markers were investigated. Wistar rats (n 54) were distributed into six groups: CdCl2; cadmium and grape juice I (1·18 g/kg per d); cadmium and grape juice II (2·36 g/kg per d); grape juice I (1·18 g/kg per d); grape juice II (2·36 g/kg per d); control. A single dose of CdCl2 (1·2 mg/kg body weight (BW)) was injected intraperitoneally and the grape juice was administered orally for 56 d. The results indicated that cadmium changed all reproductive and antioxidant parameters. At dosage I (1·18 g/kg BW), GJC consumption did not show the effects against cadmium-induced damages. In contrast, at dosage II (2·36 g/kg BW), the GJC improved the gonadosomatic index (P= 0·003), serum testosterone levels (P= 0·001), the relative weight of epididymis (P= 0·013) and ventral prostate (P= 0·052), the percentage of normal sperm (P= 0·001), and histopathological and histomorphometrical parameters. In addition, at this dosage, normalisation of the enzymatic activity of superoxide dismutase (P= 0·001) and of testicular levels of glutathione (P= 0·03) were observed. The parameters of the non-exposed rats did not depict significant alterations. In conclusion, the product was able to act as a protector of reproductive function against cadmium-induced damage. Such a property was expressed in a dose-dependent manner as the more effective dose was dosage II. The GJC acted possibly by antioxidant mechanisms.

Heme oxygenase-1 induction protects against hypertension associated with diabetes: effect on exaggerated vascular contractility

Disturbances in vascular reactivity are important components of diabetes-evoked hypertension. Heme oxygenase-1 (HO-1) is a homeostatic enzyme upregulated in stress. This study aims to investigate the protective effect of HO-1 against diabetes-evoked hypertension. Rats were left 8 weeks after diabetes induction with streptozotocin to induce vascular dysfunction in the diabetic groups. HO-1 inducers, hemin and curcumin, were daily administrated in the last 6 weeks in the treated groups after 2 weeks of induction. Then, at the end of the study (8 weeks), HO-1 protein level was assessed by immunofluorescence; blood pressure (BP) was recorded; isolated aorta reactivity to phenylephrine (PE) and KCl was studied; reactive oxygen species (ROS) generation was determined; and serum level of glucose, advanced glycation end products (AGEs), and tumor necrosis factor alpha (TNF-α) were determined. While not affected by diabetes, HO-1 protein expression was strongly induced by hemin or curcumin administration. Compared with control animals, diabetes increased systolic and pulse BP. Induction of HO-1 by hemin or curcumin significantly reduced elevated systolic BP and abolished elevated pulse BP without affecting the developed hyperglycemia or AGEs level. The possibility that alterations in vascular reactivity contributed to diabetes-HO-1 BP interaction was investigated. Diabetes increased contractile response of the aorta to PE and KCl, while HO-1 induction by curcumin or hemin prevented aorta-exaggerated response to PE and KCl. Furthermore, the competitive HO inhibitor, tin protoporphyrin, abolished the protective effect of hemin. Diabetes was accompanied with elevated level of TNF-α and ROS generation, while HO-1 induction abrogated increased TNF-α and ROS generation. Collectively, induction of HO-1 protects against hypertension associated with diabetes via ameliorating exaggerated vascular contractility by reducing TNF-α and aortic ROS levels.

Ovarian toxicity induced by dietary cadmium in hen

To investigate the toxicity of cadmium (Cd) on female reproduction in birds, this study was conducted to determine the changes in biochemical parameters of serum and ovary tissue caused by dietary cadmium in hens. Ninety 50-day-old hyline white hens were randomly divided into three groups (30 hens per group): a control group was fed with basal diet, a low dose group was fed with basal diet containing 140 mg/kg CdCl(2) and a high dose group was fed with basal diet containing 210 mg/kg CdCl2. After being treated with Cd for 20, 40 and 60 days, ovary and serum samples were collected and examined for Cd content, histological evaluations, malondialdehyde (MDA) content, glutathione peroxidase (GPx) content, activities of superoxide dismutase (SOD), nitric oxide (NO) content, nitric oxide synthase (NOS) activity, and serum estradiol and progestogen levels. The results showed that the content of Cd, MDA, NO and the activity of NOS in ovary and serum were increased (P < 0.05), while the level of GPx and the activity of SOD were decreased (P < 0.05) in low dose and high dose groups. A time- and dose-dependent correlation was observed between serum and ovary tissue cadmium levels. The number of apoptotic cells in the ovary was increased in the Cd treatment group (P < 0.05). Extensive damage was observed in the ovary. The level of estradiol and progestogen in the serum of low dose and high dose groups was decreased significantly (P < 0.05). It indicated that Cd exposure resulted in oxidative damage of hens' ovary tissue by altering antioxidant defense enzyme systems, lipid peroxidation, apoptosis and endocrine disturbance which may be possible underlying reproductive toxicity mechanisms induced by Cd.

Intracellular accumulation of bilirubin as a defense mechanism against increased oxidative stress

Antioxidant, anti-inflammatory and anti-atherogenic effects have been associated with elevations of unconjugated bilirubin (UCB) in serum and with the induction of heme oxygenase-1 (HO-1), the rate-limiting enzyme in UCB synthesis. The aim of this study was to investigate the intracellular metabolism and antioxidant properties of UCB in human hepatoblastoma HepG2 cells and tissues of Wistar rats exposed to oxidative stressors and lipopolysaccharide (LPS), respectively. Intracellular UCB concentrations in HepG2 cells correlated with its levels in culture media (p < 0.001) and diminished lipid peroxidation in a dose-dependent manner (p < 0.001). Moreover, induction of HO-1 with sodium arsenite led to 2.4-fold (p = 0.01) accumulation of intracellular UCB over basal level while sodium azide-derived oxidative stress resulted in a 60% drop (p < 0.001). This decrease was ameliorated by UCB elevation in media or by simultaneous induction of HO-1. In addition, hyperbilirubinemia and liver HO-1 induction in LPS-treated rats resulted in a 2-fold accumulation of tissue UCB (p = 0.01) associated with enhanced protection against lipid peroxidation (p = 0.02). In conclusion, hyperbilirubinemia and HO-1 induction associated with inflammation and oxidative stress increase intracellular concentrations of UCB, thus enhancing the protection of cellular lipids against peroxidation. Therefore, the previously reported protective effects of hyperbilirubinemia and HO-1 induction are at least in part due to intracellular accumulation of UCB.

Pro-healing potential of hemin: an inducer of heme oxygenase-1

Hemin induces heme oxygenase (HO), an enzyme which degrades heme in a rate-limiting manner and has an important role in cellular protection against oxidative stress and apoptosis. This HO inducer may be of potential therapeutic value in wound healing and inflammation. To identify the beneficial activity of HO vis a vis wound healing, hemin was used as inducer of HO in rats using a full-thickness cutaneous wound model. Hemin treatment increased cellular proliferation and collagen synthesis as evidenced by increase in wound contraction and hydroxyproline and glucosamine contents. mRNA expression of cytokines endorsed fast healing as was indicated by inhibition of pro-inflammatory cytokines such as ICAM-1 and TNF-alpha and up-regulation of anti-inflammatory cytokine IL-10.

Testis response to low doses of cadmium in Wistar rats

Although it is well known that cadmium (Cd) causes adverse effects on male rat reproductive organs, few studies have quantified alterations caused by its low doses. Quantification of these alterations, especially in the testis, was measured using morphometry. A single dose of cadmium chloride (1 or 1.2 mg/kg BW) was injected i.p. in adult rats, killed after 7 or 56 days. The lower dose caused slight alterations as measured by morphometrical analysis. The higher dose caused significant reduction in testis and epididymis weight, gonadossomatic index and length of seminiferous tubule (ST) after 7 and 56 days. Cadmium significantly reduced the ST diameter after 56 days. Decreased volume density of ST, after 7 and 56 days, was accompanied by an increase in interstitium volume density. The damage caused by the dose of 1.2 mg/kg can be clearly observed with light microscope. After 7 days, the tubule lumens were filled with degenerated germ cells and multinucleated spermatid aggregates. Vacuolization of the seminiferous epithelium was also observed. After 56 days, increased damage resulted in vacuolated ST, consisting only of Sertoli cells. Scanning electron microscopy examination of the testis showed that, in the group cadmium treated (1.2 mg/kg) and killed after 56 days, the interstitial tissue presents a compact and fibrous appearance with absence of fenestrae. The seminiferous epithelium height diminished and the absence of spermatozoa can be noted. The results show that a very small difference of Cd dose causes a sudden increase in testicular damage, apparently overpowering this tissue's natural defences.

Induction of heme oxygenase-1 with hemin attenuates hippocampal injury in rats after acute carbon monoxide poisoning

Carbon monoxide (CO) poisoning is a major cause of brain injury and mortality; delayed neurological syndrome (DNS) is encountered in survivors of acute CO exposure. The toxic effects of CO have been attributed to oxidative stress induced by hypoxia. Heme oxygenase-1 (HO-1) is the inducible heme oxygenase isoform, and its induction acts as an important cellular defense mechanism against oxidative stress, cellular injury and disease. In this study, we examined the functional roles of HO-1 induction in a rat model of CO-exposured hippocampal injury. We report that acute CO exposure produces severe hippocampal injury in rats. However, hemin pretreatment reduced both the CO-induced rise in hippocampal water content and levels of neuronal damage in the hippocampus; survival rates at 24 h were significantly improved. Upregulation of HO-1 by hemin pretreatment resulted in a significant decrease in hippocampal levels of malondialdehyde (MDA), a marker of oxidative stress; levels of pro-apoptotic caspase-3 were also reduced. In contrast, inhibition of HO activity by administration of tin protoporphyrin IX (SnPP, a specific inhibitor of HO) abolished the neuroprotective effects of HO-1 induction. These data suggested that the upregulation of endogenous HO-1 expression therefore plays a pivotal protective role in CO neurotoxicity. Though the precise mechanisms underlying hemin-mediated HO-1 induction and neuroprotection are not known, these may involve the anti-oxidant and anti-apoptotic effects of HO-1 enzyme activity.