Potential testicular toxicity of sodium nitrate in adult rats

Ameliorative action of eugenol on nitrate induced reproductive toxicity in male rats

There is a great concern for studies to prevent nitrate (NO3) induced male reproductive toxicity as it might lead to infertility. Therefore, the study was aimed to investigate the ameliorative effects of eugenol on NO3 induced male reproductive toxicity in wistar rats. Adult male rats were randomly divided into five groups (n=5). The first group was served as control, the second and third group of rats were treated with 100 mg/kg bw of sodium nitrate (NaNO3) and NO3 contaminated ground water respectively. The fourth and fifth group of rats were orally intubated with eugenol (100 mg/kg bw) and then exposed to NaNO3 and NO3 contaminated ground water respectively. The treatment was continued for 52 days. Nitrate exposure significantly decreased the sperm motility, testicular 3-beta-hydroxysteroid dehydrogenase activity, serum concentration of testosterone, activities of superoxide dismutase and catalase in testis and spermatozoa and different categories of germ cells in stage VII of spermatogenesis. Further, there was significant increase in sperm abnormality and levels of nitrite (NO2) and malondialdehyde in testis and spermatozoa of NO3 treated rats. In addition, NO3 exposure distorted the histological architecture of seminiferous tubules of testis. It was established that NO3 induced high production of NO2 affected spermatogenesis, steroidogenesis and sperm motility. However, in the present study, pretreatment of eugenol prevented NO3 induced reproductive alterations by decreasing the level of NO2. These findings clearly showed the protective action of eugenol against NO3 induced oxidative stress in male reproductive system.

Modulatory effects of Moringa oleifera leaf extract on sodium nitrate-induced experimental colitis via regulation of P53, Ki-67 and PCNA biomarkers

BACKGROUND

Ulcerative colitis is a risk factor for colorectal carcinoma. Different mechanisms are related to colitis like apoptosis and hyperproliferation. Moringa oleifera leaves extract (MO) provides a promising option to overcome the risk.

PURPOSE

To examine the colonic changes in a rat model of colitis induced by sodium nitrate (SN) and study the effects of MO.

STUDY DESIGN

Eight adult male rats were allocated in each of the three group; control (distilled water), SN (100 mg/kg/day, orally via gastric gavage), and SN + MO (100 mg/kg/day, orally via gastric gavage).

METHODS

Body weight was measured after the end of the experiment. Colonic homogenates were tested for levels of oxidative stress indicators. Immunohistochemistry for P53, PCNA and Ki-67 was performed. Fresh colon specimens were used for quantitative real-time PCR for assessment of P53, PCNA and Ki-67 gene expression.

RESULTS

SN group revealed a significant decreased weight (p = 0.002). MDA and NO levels were higher with SN administration than with MO co-administration (p= 0.04, 0.01 respectively). GSH level was reduced in SN group (p = 0.02) and significantly increased with MO intake (p = 0.04). SN-induced colonic destructive changes were reversed with MO. P53, PCNA and Ki-67 levels of gene expression were reduced in SN + MO group than SN group (P = 0.007, 0.02, 0.001 respectively).

CONCLUSION

MO protected the colonic mucosa against SN-induced changes regulating apoptosis, and cell proliferation.

Nitrate in Maternal Drinking Water during Pregnancy and Measures of Male Fecundity in Adult Sons

Animal studies indicate deleterious effects of nitrate exposure on fecundity, but effects in humans are unknown, both for the prenatal and postnatal periods. We aimed to investigate if exposure to nitrate in maternal drinking water during the sensitive period of fetal life is associated with measures of fecundity in the adult sons. In a sub-analysis, the potential effects of nitrate exposure in adulthood were investigated. This cohort included 985 young adult men enrolled in The Fetal Programming of Semen Quality Cohort (FEPOS). Semen characteristics, testes volume and reproductive hormones were analyzed in relation to nitrate concentration in maternal drinking water, using a negative binomial regression model. The nitrate concentration in drinking water was obtained from monitoring data from Danish waterworks that were linked with the mothers' residential address during pregnancy. The median nitrate concentration in maternal drinking water was 2 mg/L. At these low exposure levels, which are far below the World Health Organization's (WHO) guideline value of 50 mg/L, we did not find indications of harmful effects of nitrate on the investigated measures of male fecundity.

Drinking water nitrate and risk of pregnancy loss: a nationwide cohort study

BACKGROUND

Nitrate contamination is seen in drinking water worldwide. Nitrate may pass the placental barrier. Despite suggestive evidence of fetal harm, the potential association between nitrate exposure from drinking water and pregnancy loss remains to be studied. We aimed to investigate if nitrate in drinking water was associated with the risk of pregnancy loss.

METHODS

We conducted a nationwide cohort study of 100,410 pregnancies (enrolled around gestational week 11) in the Danish National Birth Cohort (DNBC) during 1996-2002. Spontaneous pregnancy losses before gestational week 22 were ascertained from the Danish National Patient Registry and DNBC pregnancy interviews. Using the national drinking water quality-monitoring database Jupiter, we estimated the individual and time-specific nitrate exposure by linking geocoded maternal residential addresses with water supply areas. The nitrate exposure was analyzed in spline models using a log-transformed continuous level or classified into five categories. We used Cox proportional hazards models to estimate associations between nitrate and pregnancy loss and used gestational age (days) as the time scale, adjusting for demographic, health, and lifestyle variables.

RESULTS

No consistent associations were found when investigating the exposure as a categorical variable and null findings were also found in trimester specific analyses. In the spline model using the continuous exposure variable, a modestly increased hazard of pregnancy loss was observed for the first trimester at nitrate exposures between 1 and 10 mg/L, with the highest. adjusted hazard ratio at 5 mg/L of nitrate of 1.16 (95% CI: 1.01, 1.34). This trend was attenuated in the higher exposure ranges.

CONCLUSION

No association was seen between drinking water nitrate and the risk of pregnancy loss when investigating the exposure as a categorical variable. When we modelled the exposure as a continuous variable, a dose-dependent association was found between drinking water nitrate exposure in the first trimester and the risk of pregnancy loss. Very early pregnancy losses were not considered in this study, and whether survival bias influenced the results should be further explored.

Assessment of sodium nitrate (NaNO3) effects on the reproductive system, liver, pancreas and kidney of male rats

Nitrate (NO₃) toxicity is a serious global issue that results in impairment of physiological systems of our body. The present study aimed to investigate the effects of different concentration of NaNO₃ (10, 100, 500 and 1000 mg/kg bw) on the male reproductive system, liver, kidney and pancreas. Adult male Wistar rats were divided into five groups of five animals each (n = 5). The first group served as controls. The second, third, fourth and fifth groups of rat were orally intubated with 10, 100, 500 and 1000 mg/kg bw of NaNO₃ for 52 days. After the treatment period, the rats were sacrificed and NO₃ induced alterations on selected organs were assessed. There was a dose dependent decrease in sperm motility, serum concentration of testosterone, body weight and organ weight, and increase in abnormal sperm morphology in the NaNO₃ treated groups compared with the controls. Further, histological analysis confirmed that NO₃ induced toxicity. Shrunken seminiferous tubules and loss of spermatids in testes, shrinkage of acinar cells of the pancreas, sinusoidal congestion and necrosis in the liver, atrophy of glomeruli and congestion of renal tubules of the kidney were the histological alterations observed in rats treated with100 and 500 mg/kg NaNO₃. However, 100% mortality was observed in rats treated with 1000 mg/kg NaNO₃. The present study clearly demonstrated the toxic effects of NaNO₃ on both the reproductive system and other organs of the body. The study might inform human studies; where in the chances of male infertility may be more a problem for individuals in areas with NO₃-rich ground water.

Nitrate in Drinking Water and Time to Pregnancy or Medically Assisted Reproduction in Women and Men: A Nationwide Cohort Study in the Danish National Birth Cohort

Purpose

No studies have investigated if drinking water nitrate affects human fecundity. Experimental studies point at detrimental effects on fetal development and on female and male reproduction. This cohort study aimed to explore if female and male preconception and long-term exposure to nitrate in drinking water was associated with fecundability measured as time to pregnancy (TTP) or use of medically assisted reproduction (MAR) treatment.

Methods

The study population consisted of pregnant women recruited in their first trimester in 1996–2002 to the Danish National Birth Cohort. Preconception drinking-water nitrate exposure was estimated for the pregnant women (89,109 pregnancies), and long-term drinking water nitrate exposure was estimated from adolescence to conception for the pregnant women (77,474 pregnancies) and their male partners (62,000 pregnancies) by linkage to the national drinking water quality-monitoring database Jupiter. Difference in risk of TTP >12 months or use of MAR treatment between five exposure categories and log-transformed continuous models of preconception and long-term nitrate in drinking water were estimated. Binominal regression models for risk ratios (RR) were adjusted for age, occupation, education, population density, and lifestyle factors.

Results

Nitrate in drinking water (median preconception exposure: 1.9 mg/L; median long-term exposure: 3.3 mg/L) was not associated with TTP >12 months or use of MAR treatment, neither in the categorical nor in the continuous models.

Conclusion

We found no association between preconception or long-term exposure to drinking water nitrate and fecundability.

Association between Drinking Water Nitrate and Adverse Reproductive Outcomes: A Systematic PRISMA Review

One in six couples experience fertility problems. Environmental factors may affect reproductive health; however, evidence is lacking regarding drinking water nitrates and outcomes of male and female fertility. The aim of this study was to investigate if exposure to nitrates in drinking water is associated with adverse reproductive outcomes in humans, and animals of fertile age. We conducted a systematic literature search and included case-control studies, cohort studies, and randomized control trials reporting on the association between drinking water nitrate exposure of men, women, or animals and adverse reproductive outcomes, specified as: Semen quality parameters, time to pregnancy (TTP), pregnancy rates, assisted reproductive technologies (ART), and spontaneous abortion. Findings were reported in a narrative synthesis. A total of 12 studies were included. The only human study included reported a decrease in spontaneous abortion at any detectable nitrate level. Overall, the 11 included animal studies support a potential negative effect on semen quality parameters but report equivocal results on TTP and number of offspring produced, and higher risk of spontaneous abortion. In conclusion, animal studies indicate possible effects on semen quality parameters and spontaneous abortion. However, with a few studies, including some with methodological limitations and small sample sizes, caution must be applied when interpreting these results.

The effect of prolonged dietary sodium nitrate treatment on the hypothalamus-pituitary-gonadal axis and testicular structure and function in streptozotocin-induced diabetic male rats

The aim of this study was to evaluate the effect of prolonged dietary nitrate supplementation on the gonadotropin level, testicular histology and morphometry, expression of miR-34b and p53 mRNA, and spermatogenesis in streptozotocin-induced diabetic male rats.

METHODS

Fifty male Wistar rats were divided into 5 groups: Control (C), control + nitrate (CN), diabetes (D), diabetes + insulin (DI), and diabetes + nitrate (DN). Diabetes was induced using 45 mg kg^-1 of streptozotocin intraperitoneally. Rats in the CN and DN groups were administered sodium nitrate in drinking water (100 mg L^-1). NPH insulin (2-4 U d^-1) was injected subcutaneously in the DI group for 2 months. Nitrate and insulin supplementation was started one month after confirmation of diabetes.

RESULTS

Nitrate supplementation in the DN group significantly increased the body weight (p < 0.05), sperm parameters (p < 0.001), indices of spermatogenesis (p < 0.001), and testis histopathology as well as decreased the blood glucose level (p < 0.001) compared to the untreated diabetic group, although it had no significant effect on testicular parameters, LH and FSH levels. Nitrate administration in the DN group also decreased miR-34b (p < 0.001) and p53 mRNA (p < 0.001) expression, and increased serum insulin and NOx levels compared to the untreated diabetic rats.

CONCLUSIONS

Chronic nitrate supplementation in streptozotocin-induced diabetic rats improved fertility parameters, which may be associated with increased miR-34b and decreased p53 mRNA.

Pumpkin seed oil alleviates oxidative stress and liver damage induced by sodium nitrate in adult rats: biochemical and histological approach

BACKGROUND

Nitrate (NO3) is the most common chemical contaminant in the world's ground water aquifer. Oxidative stress has been proposed as a possible mechanism involved in NO3 toxicity on non-target organism.

OBJECTIVES

The current study aimed to elucidate the potential protective effect of Telfairia occidentalis (pumpkin seed oil, PSO) against hepatotoxicity induced by sodium nitrate.

METHODS

Wistar rats were exposed either to NaNO3 (200 mg/kg bw) in drinking water in drinking water, or to 4ml PSO/kg bw by gavage or to their combination. Oxidative stress parameters, biochemical biomarkers and liver histopathological examination were determined.

RESULTS

Our data showed that the exposure of rats to NaNO3 caused significant changes of some haematological parameters compared to the control. In addition, there was a significant elevation of the levels of biochemical markers as that of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and lactate dehydrogenase when compared with the control. Furthermore, exposure of rats to NaNO3 induced liver oxidative stress as indicated by the increase of malondialdehyde, progressive oxidation of protein products and protein carbonyl levels. In addition, a reduction in anti-oxidant status (catalase, glutathione peroxidase, glutathione-S-transferase and superoxide dismutase, reduced glutathione and vitamin C) was observed.

CONCLUSION

Co-administration of PSO to the NaNO3 restored most parameters cited above to near-normal values. Therefore, the present investigation revealed the ability of PSO to attenuate NaNO3-induced oxidative damage.

Amelioration of titanium dioxide nanoparticle reprotoxicity by the antioxidants morin and rutin

The present study aimed to examine the ameliorative effects of morin and rutin on the reproductive toxicity induced by titanium dioxide nanoparticles (TiO₂NPs) in male rats. A total of seventy adult male Sprague-Dawley rats were randomly divided into seven groups, each comprising ten rats. Nanoreprotoxicity was induced by treating rats with TiO₂NPs at a dosage of 300 mg/kg body weight for 30 days. Morin (30 mg/kg body weight) and rutin (100 mg/kg body weight) were co-administered with or without TiO₂NPs to rats either individually or combined. Only distilled water was administered to the control group. The results showed that TiO₂NPs enhanced oxidative stress, indicated by reduced levels of antioxidants such as superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) in testicular tissues, and increased levels of the lipid peroxidation marker malondialdehyde (MDA). TiO₂NPs significantly reduced the levels of sex hormones (testosterone, FSH, and LH), reduced sperm motility, viability, and sperm cell count, and increased sperm abnormalities, in addition to damaging the testicular histological architecture. TiO₂NPs resulted in the downregulation of 17β-HSD and the upregulation of proapoptotic gene (Bax) transcripts in the testicular tissues. Conversely, morin and/or rutin had a protective effect on testicular tissue. They effectively counteracted TiO₂NP-induced oxidative damage and morphological injury in the testis by conserving the endogenous antioxidant mechanisms and scavenging free radicals. Thus, we suggest that morin and rutin could be used to alleviate the toxicity and oxidative damage associated with TiO₂NP intake.

Hyparrhenia hirta: A potential protective agent against hematotoxicity and genotoxicity of sodium nitrate in adult rats

The present study was carried out to examine the adverse hematotoxic and genotoxic effects of water nitrate pollution on male adult rats and the use of hyparrhenia hirta methanolic extract in alleviating these effects. Sodium nitrate (NaNO3 ) was administered to adult rats by oral gavage at a dose of 400 mg kg(-1) bw daily for 50 days, while hyparrhenia hirta methanolic extract was given by drinking water at a dose of 1.5 mg mL(-1) (200 mg kg(-1) bw). The NaNO3 -treated group showed a significant decrease in red blood cell count, hemoglobin and hematocrit and a significant increase in total white blood cell, in neutrophil and eosinophil counts. Platelet count, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration remained unchanged in treated groups compared to those of controls. Meanwhile, the results showed a marked reduction in the antioxidant enzyme activities, such as superoxide dismutase, catalase, and glutathione peroxidase, along with an elevation in the level of lipid peroxidation and a reduction in the total glutathione content, indicating the induction of oxidative stress in the erythrocytes of NaNO3 -treated group. Interestingly, NaNO3 treatment showed a significant increase in the frequencies of total chromosomal aberrations, aberrant metaphases and micronucleus in bone-marrow cells. The oxidative stress induced by nitrate treatment might be the major cause for chromosomal rearrangements as free radicals leading to DNA damage. Hyparrhenia hirta methanolic extract appeared to be effective against hematotoxic and genotoxic changes induced by nitrate, as evidenced by the improvement of the markers cited above.

Effects of long-term dietary nitrate supplementation in mice

Background

Inorganic nitrate (NO3-) is a precursor of nitric oxide (NO) in the body and a large number of short-term studies with dietary nitrate supplementation in animals and humans show beneficial effects on cardiovascular health, exercise efficiency, host defense and ischemia reperfusion injury. In contrast, there is a long withstanding concern regarding the putative adverse effects of chronic nitrate exposure related to cancer and adverse hormonal effects. To address these concerns we performed in mice, a physiological and biochemical multi-analysis on the effects of long-term dietary nitrate supplementation.

Design

7 week-old C57BL/6 mice were put on a low-nitrate chow and at 20 weeks-old were treated with NaNO₃ (1 mmol/L) or NaCl (1 mmol/L, control) in the drinking water. The groups were monitored for weight gain, food and water consumption, blood pressure, glucose metabolism, body composition and oxygen consumption until one group was reduced to eight animals due to death or illness. At that point remaining animals were sacrificed and blood and tissues were analyzed with respect to metabolism, cardiovascular function, inflammation, and oxidative stress.

Results

Animals were supplemented for 17 months before final sacrifice. Body composition, oxygen consumption, blood pressure, glucose tolerance were measured during the experiment, and vascular reactivity and muscle mitochondrial efficiency measured at the end of the experiment with no differences identified between groups. Nitrate supplementation was associated with improved insulin response, decreased plasma IL-10 and a trend towards improved survival.

Conclusions

Long term dietary nitrate in mice, at levels similar to the upper intake range in the western society, is not detrimental.

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Long term dietary nitrate supplementation for 17 months in mice.

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Nitrate treatment in the upper range in the western society diet, has no adverse health effects.

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Chronic nitrate intake in mice improves fasting insulin and insulin response.

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Cardiovascular and inflammatory parameters were unchanged after long-term dietary nitrate treatment.

Biochemical and molecular studies on the possible influence of the Brassica oleracea and Beta vulgaris extracts to mitigate the effect of food preservatives and food chemical colorants on albino rats

This study aimed to investigate the biochemical influence of broccoli and beet extracts on selected individual additives NaNO2 or sunset yellow treated rats, in addition to the gene expression of some antioxidant enzymes. Forty-two male rats were assigned to seven groups of six rats in each group. The control group was fed a diet without an additive for four weeks. Group (2) received NaNO2, groups (3) received NaNO2 co-administered with broccoli extract (4) NaNO2 co-administered with beet extracts, Group (5) received sunset yellow, Group (6) received sunset yellow co-administered with broccoli extract, and Group (7) received sunset yellow co-administered with beet extract, for four weeks. At the end of the experiment, blood, liver, kidney, and brain samples were taken for biochemical and/or molecular analysis. The mRNA expression of antioxidant enzymes was determined by reversing transcriptase-polymerase chain reaction (RT-PCR). The obtained results revealed that rats co-administered with beet or broccoli extracts had a significant decrease in serum levels of AST, ALT, ALP, urea, total lipids, and triglycerides, as well as a significant increase in reduced glutathione (GSH), glutathione peroxidase (GSH-px), and superoxide dismutase (SOD) enzyme activities, compared to the normal control group. Oral administration of NaNO2 or sunset yellow caused a significant increase in serum levels of AST, ALT, ALP, urea, total lipids, and triglycerides, as well as a significant decrease in GSH, GSH-px, and SOD compared to the positive group. In conclusion, this study showed that broccoli and beet extracts have a protective effect against NaNO2 or sunset yellow in rat treated groups.

DNA content alterations in Tetrahymena pyriformis macronucleus after exposure to food preservatives sodium nitrate and sodium benzoate

The toxicity, in terms of changes in the DNA content, of two food preservatives, sodium nitrate and sodium benzoate was studied on the protozoan Tetrahymena pyriformis using DNA image analysis technology. For this purpose, selected doses of both food additives were administered for 2 h to protozoa cultures and DNA image analysis of T. pyriformis nuclei was performed. The analysis was based on the measurement of the Mean Optical Density which represents the cellular DNA content. The results have shown that after exposure of the protozoan cultures to doses equivalent to ADI, a statistically significant increase in the macronuclear DNA content compared to the unexposed control samples was observed. The observed increase in the macronuclear DNA content is indicative of the stimulation of the mitotic process and the observed increase in MOD, accompanied by a stimulation of the protozoan proliferation activity is in consistence with this assumption. Since alterations at the DNA level such as DNA content and uncontrolled mitogenic stimulation have been linked with chemical carcinogenesis, the results of the present study add information on the toxicogenomic profile of the selected chemicals and may potentially lead to reconsideration of the excessive use of nitrates aiming to protect public health.

Heavy oil fraction induces the dysplastic sperm in male mouse

Heavy oil is one of the most serious pollutants in marine ecosystem. The poisonous influences of the chemical substances contained in heavy oil on many kinds of marine organisms are widely studied. However, the influence of the chemical compounds in heavy oil on our health has not been cleared yet. In order to reveal the poisonous influences of these chemical compounds on mammalian reproductive system, water-soluble fraction (WSF) extracted from heavy oil was administrated to mice for 2 weeks. WSF-administrated mice were crossed with either WSF- or distilled water-administrated group for mating experiment. When WSF-administrated male mice were used as a father, it reduced not only mating ratio, but also neonatal male ratio. The numbers of sperms of WSF-administrated male mice were decreased. In addition, abnormality of sperms such as bent or twisted tail was increased approximately 6-fold by WSF intake. The level of testosterone in serum from WSF-administrated mice was lower than that from control mice. Testosterone is the most important for the spermatogenesis in vertebrate. It is supposed from these findings, the decrease in the number of sperms may relate with the reduction of sex hormone level in serum. It is suggested from these results that the chemical substances in WSF affected the sperm function in reproductive system of male mice.