Protection of sodium arsenite-induced ovarian toxicity by coadministration of L-ascorbate (vitamin C) in mature wistar strain rat

n-Butanol fraction of moringa seed attenuates arsenic intoxication by regulating the uterine inflammatory and apoptotic pathways

The adverse effects of arsenic-chelating drugs make it essential to replace invasive chelating therapy with non-invasive oral therapy for arsenic poisoning. The goal of the current investigation was to determine whether the uterine damage caused by arsenization could be repaired by the n-butanol fraction of Moringa oleifera seed (NB). The rats were orally administered with arsenic (10 mg/kg BW) for the initial 8 days, followed by NB (50 mg/kg) for the next 8 days without arsenic. The probable existence of different components in NB was evaluated by HPLC-MS. Pro and anti-inflammatory indicators were assessed by RT-PCR and western blot. ESR-α was detected via immunostaining. Arsenic-exposed rats had significantly increased lipid peroxidation and decreased antioxidant enzyme activity, which were markedly reduced after NB treatment. Weaker ESR-α expression and distorted uterine histomorphology following arsenication were retrieved significantly by NB. Meaningful restoration by NB was also achieved for altered mRNA and protein expression of various inflammatory and apoptotic indicators. Molecular interaction predicted that glucomoringin and methyl glucosinolate of moringa interact with the catalytic site of caspase-3 in a way that limits its activity. However, NB was successful in restoring the arsenic-mediated uterine hypofunction. The glucomoringin and methyl glucosinolate present in n-butanol fraction may play a critical role in limiting apoptotic event in the arsenicated uterus.

Arsenic exposure during juvenile and puberty significantly affected reproductive system development of female SD rats

Infertility affects about 10-15% couples over the world, among which a large number of cases the underlying causes are still unclear. Recent studies suggest that environmental factors may play an important role in these idiopathic infertilities. Arsenic is a heavy metal found in drinking water over the world. Its effect on the development of female reproductive system at the environmental-relevant levels is still largely unknown. To test the hypothesis that arsenic exposure during juvenile and puberty may affect sex maturation and female reproductive system development, SD rats of 3 weeks of age were exposed to arsenic with environmental-relevant levels (0, 0.02, 0.2, or 2 mg/L, n = 16/group) through drinking water for about 44 days until the rats reached adulthood (65 days of age). Arsenic exposure significantly reduced the weights of both ovary and uterus without affecting the body weight. Also, arsenic exposure disturbed estrus cycles and reduced the numbers of primordial follicles and corpora lutea while increased atretic follicles. In addition, arsenic reduced serum levels of estradiol, progesterone and testosterone but increased LH and FSH levels in dose-dependent manners. QPCR and Western blot experiments indicated arsenic selectively down-regulated ovarian steroidogenic-related proteins FSHR, STAR, CYP17A1, HSD3B1 and CYP19A1 and signaling molecules PKA-ERK-JNK-cJUN, without affecting AKT and CREB. As about reproductive capacity, arsenic-exposed dams had smaller pups, reduced litter size and lower number of male pups without a change in female pups. In conclusion, juvenile and pubertal arsenic exposures at environmental-relevant levels significantly reduced reproductive functions and capacity by adult. Since the lowest effective dose is very close to the government safety standards, the relevancy of arsenic over exposure to reproductive defects in human deserves further study.

Glutathione protects against the meiotic defects of ovine oocytes induced by arsenic exposure via the inhibition of mitochondrial dysfunctions

Accumulating evidences revealed the connections between arsenic exposure and mitochondrial dysfunctions induced reproductive toxicology. Meanwhile, production declines were found in livestock suffering from arsenic exposure. However, the connections between arsenic exposure and livestock meiotic defects remain unclear. In this study, the effects of sodium arsenite (NaAsO2) exposure during the in vitro maturation (IVM) on the meiotic potentials of ovine oocytes were analyzed. Furthermore, the effects of glutathione (GSH) supplementation on the meiotic defects of NaAsO2 exposed ovine oocytes were investigated by the assay of nuclear maturation, spindle organization, chromosome alignment, cytoskeleton assembly, cortical granule (CGs) dynamics, mitochondrial dysfunctions, reactive oxygen species (ROS) accumulation, oxidative DNA damages, cellular apoptosis, epigenetic modifications and fertilization capacities. The results showed that the meiotic defects of NaAsO2 exposed ovine oocytes were effectively ameliorated by the GSH supplementation via the inhibition of mitochondrial dysfunctions, which not only promoted the nuclear maturation, spindle organization, chromosome alignment, cytoskeleton assembly, CGs dynamic and fertilization capacities, but also inhibited the ROS accumulation, oxidative DNA damages and apoptosis of ovine MII oocytes. The abnormal expressions of 5mC, H3K4me3 and H3K9me3 in NaAsO2 exposed ovine oocytes, indicating the abnormal epimutations of DNA methylation and histone methylation, were also effectively ameliorated by the GSH supplementation. Taken together, this study confirmed the connections between arsenic exposure and meiotic defects of ovine oocytes. Meanwhile, the effects of GSH supplementation on the developmental competence of livestock oocytes, especially for these suffering from arsenic exposure were also founded, benefiting the extended researches for the GSH applications.

Toxicological screening and evaluation of anti-allergic and anti-hyperglycemic potential of Sonneratia caseolaris (L.) Engl. fruits

Background

Sonneratia caseolaris (L.) Engl. (S. caseolaris) belonging to the Sonneratiaceae family is commonly known as Ora. It is traditionally used as an astringent, antiseptic, to treat sprains, swellings, cough and in arresting hemorrhage. The ethanolic extract of S. caseolaris (L.) Engl. fruits was investigated in the present study for its toxicity as well as anti-allergic and anti-hyperglycemic potentials.

Methods

Major phenolic compounds were identified and quantified by HPLC. Behavioral change, body weight, mortality and different blood parameters were measured to assess the toxicological effect of the extract. Anti-allergic activity was evaluated using TDI-induced allergic model mice. Oral glucose tolerance test (OGTT) and STZ-induced diabetic mice were used to evaluate the anti-hyperglycemic activity.

Results

Crude extract contained ellagic acid, vanillic acid and myrecitin (27.41, 3.06 and 7.93 mg per 100 g dry extract respectively). No major toxicity was observed in both acute and sub-acute toxicity study. Oral administration of the extract significantly ameliorated TDI-induced allergic symptoms like sneezing, scratching, swelling, redness and watery rhinorrhoea in the experimental mice. The extracts also reduced the total and differential count of leukocytes in the blood. The extract treated mice showed significant reduction in blood glucose, SGOT, SGPT, cholesterol, triglycerides, urea, creatinine and bilirubin level.

Conclusions

S. caseolaris contains bioactive phytoconstituents which may be the possible precursors to isolate and characterize the novel compounds targeting the diseases like allergy and diabetes.

Osteoprotective effects of kefir fortified with omega-3 and vitamin C in ovariectomized rats

Nutritional interventions can be valuable for the prevention of postmenopausal osteoporosis. This study aimed to investigate the effects of kefir fortified with omega-3 and vitamin C on the bone and uterus parameters of ovariectomized rats. Seventy-seven female Sprague-Dawley rats were ovariectomized or sham-operated. The ovariectomized rats were assigned to six groups and received 1 ml/day of distilled water (OVX group), milk, kefir, kefir fortified with omega-3 (kefir+ω3), kefir fortified with vitamin C (kefir+vit-C) or kefir fortified with omega-3 and vitamin C (kefir+ω3+vit-C) for 12 weeks. The sham group also received 1ml/day of distilled water. Subsequently, bone mineral content (BMC) and bone mineral density (BMD) of various bones were assessed. Femurs and uteri were harvested for bone ash analysis and histopathological examinations, respectively. Sera were analyzed for carboxy-terminal cross-linked telopeptide of type 1 collagen, procollagen type 1 amino-terminal propeptide, calcium, phosphorous, tumor necrosis factor-α (TNF-α) and total antioxidant capacity levels. Ovariectomy resulted in significant reduction in bone density (P<0.05). Kefir+ω3+vit-C significantly improved BMC of lumbar spine (0.699±0.027 g compared with 0.580±0.018 in the OVX group), and kefir, kefir+vit-C and kefir+ω3+vit-C significantly increased BMD of tibia (0.118±0.003 g/cm², 0.119±0.001 and 0.120±0.004 compared with 0.102±0.005 in the OVX group). Moreover, ovariectomy markedly elevated TNF-α level, which was significantly reversed by kefir+ω3+vit-C. Significant atrophy of the uterus was observed following ovariectomy, although the uterus parameters did not change by any of the interventions. In conclusion, kefir fortified with omega-3 and vitamin C may have protective effects against bone loss through suppressing inflammation.

Effects of heavy metals on reproduction owing to infertility

The reproductive performance of most of the species is adversely affected by hazardous heavy metals like lead, cadmium, mercury, arsenic, zinc, and copper. Heavy metals are liberated in the environment by natural sources like rock weathering, volcanic eruption, and other human activities like industrial discharge, mineral mining, automobile exhaust, and so forth. Heavy metals alter several reproductive functions in both males and females like a decrease in sperm count, motility, viability, spermatogenesis, hormonal imbalance, follicular atresia, and delay in oocyte maturation, and so forth, and thus, forms an important aspect of reproductive toxicology. The present review compiles toxicity aspects of various heavy metals and their efficacy and mechanism of action in mammals.

Casein- and pea-enriched high-protein diet can take care of the reprotoxic effects of arsenic in male rats

Arsenic toxicity is a significant health problem featured with several incidents of male reproductive dysfunctions. We studied the protective effects of a casein- and pea-enriched formulated high-protein diet (FHPD) on arsenic-mediated testicular dysfunctions in rats. Adult male rats sustained on either a benchmark diet (n = 8) or an isocaloric FHPD (n = 8) were gavaged with arsenic trioxide (3mg/kg body wt/rat/day) for 30 consecutive days. A vehicle-fed group (n = 8) maintained on the standard diet served as control. The arsenic-treated group continued on the standard diet had a significantly reduced testicular and accessory sex organs weights. They exhibited decreased count, motility, viability and disrupted plasma membrane integrity of caudal spermatozoa with a higher incidence of gross morphological anomalies and DNA damage. Attenuated steroidogenic enzyme activities and low serum testosterone level vouched for a compromised state of testicular steroidogenesis. An increased testicular malondialdehyde and protein carbonyl contents coupled with impaired activities of antioxidant enzymes and free radical scavengers mirrored a situation of exacerbated testicular oxidative imbalance and disrupted redox homeostasis. FHPD, by and large, countermanded testicular steroidogenesis and antioxidant defence system and revoked the ill effects of arsenic. We conclude that specific protein-enriched diet may serve as prospective weaponry in encountering the arsenic-threatened testicular functions.

Effect of α-lipoic acid on spatial memory and structural integrity of developing hippocampal neurons in rats subjected to sodium arsenite exposure

BACKGROUND

Exposure to arsenic has been reported to affect the nervous system in a number of ways. Various epidemiological studies suggest cognitive impairment in subjects following exposure to environmental arsenic. The goal of the present study was to determine if supplementation of exogenous α-lipoic acid (ALA) could ameliorate sodium arsenite (NaAsO₂) induced adverse effects on learning and memory and synaptic connectivity in rat hippocampus.

METHODS

Accordingly, NaAsO₂ alone (1.5/2.0 mg/kg bw) or NaAsO₂ along with ALA (70 mg/kg bw) was administered by intraperitoneal (i.p.) route from postnatal day (PND) 4-17 to Wistar rat pups (experimental groups) and the Control groups received either distilled water or no treatment at all. After carrying out Elevated Plus Maze (EPM) and Morris Water Maze (MWM) test, the fresh brain tissues were collected on PND 18 and processed for Golgi Cox staining.

RESULTS

Observations of MWM test revealed impaired learning and memory in iAs alone treated animals as against those co-exposed to iAs and ALA. In Golgi stained hippocampal sections of iAs alone treated animals, decreased dendritic arborization and reduced number of spines in pyramidal neurons (CA1) and granule cells (DG) was observed whereas neuronal morphology was preserved in the controls and ALA supplemented groups CONCLUSIONS: These observations are suggestive of beneficial effects of ALA on iAs induced effects on learning and memory as well as on hippocampal neuronal morphology.

Arsenic and smokeless tobacco exposure induces DNA damage and oxidative stress in reproductive organs of female Swiss albino mice

Arsenic contamination in the groundwater of Southern Assam, India is well-documented. A specific type of smokeless tobacco (sadagura, SG) is highly prevalent among the local population. Thus, the present study is aimed to evaluate the toxicological implications of arsenic and smokeless tobacco co-exposure on the reproductive health of female mice. The estrous cycle of experimental animals was monitored for 30 days. Histopathological studies and comet assay of ovarian and uterine tissues were performed after 30 days of exposure to SG and arsenic (sodium arsenite, SA). Oxidative stress was estimated biochemically by taking tissue glutathione, lipid peroxidation (LPO), and superoxide dismutase activity as endpoints. Our findings indicated a prolonged diestrus phase in the SG + L + SA group (p < 0.001). Histopathological study revealed abnormal tissue architecture in treated groups. Comet assay study showed that SG + SA exposure significantly induced DNA damage in test animals. The elevated LPO level in the SG + SA group indicated oxidative stress generation in the reproductive tissues. The present study suggests that female reproductive organs are vulnerable to SA and SG and oxidative stress generation may be the possible mechanism behind DNA damage, impaired follicular growth, atresia, and altered estrous cycle in the mice test system.

High-Protein Diet Ameliorates Arsenic-Induced Oxidative Stress and Antagonizes Uterine Apoptosis in Rats

Arsenic toxicity purportedly threats a broad spectrum of female reproductive functions. We investigated the remedial role of a casein- and pea protein-enriched high-protein diet (HPD) in combating the arsenic insult. Cyclic female rats maintained on standard diet (n = 6) or an isocaloric HPD (n = 6) were gavaged with As₂O₃ at 3 mg/kg BW/rat/day (n = 12) for 28 days. Vehicle-fed rats (n = 6) maintained on the standard diet served as the control. We monitored the estrus cycles and performed the histomorphometric analyses of the uterus and ovary. Uterine luminal epithelial (ULE) ultrastructure was appraised by scanning electron microscopy. Uterine oxidative stress was evaluated in the forms of ROS generation and activities of the ROS scavengers. The uterine apoptotic manifestation was blueprinted by Western blot analysis of caspase-3 and Bax expression. Arsenic treatment arrested the follicular maturation and disrupted the estrus cycles with a typical increase in the diestrus index. Shrunken endometrial glands and thinned microvilli density of the ULE reflected loss of cell polarity and mislaid uterine homeostasis. Increased ROS generation and attenuated activities of the ROS scavengers marked a state of uterine oxidative imbalance and loss of redox regulation. Superfluous expression of procaspase-3, cleaved caspase-3, and Bax mirrored an inflated state of uterine apoptosis. HPD supplementation, by and large, counteracted these arsenic impacts and maintained the frameworks close to the control levels. In conclusion, arsenic mediates its reproductive toxicity, at least in part, by upsetting the uterine ROS homeostasis and redox regulation. Pea proteins and casein-supplemented HPD can counteract the arsenic effects and maintain the reproductive functions.

Sodium Arsenite Injection Induces Ovarian Oxidative Stress and Affects Steroidogenesis in Rats

Oxidative stress is involved in the regulation of mammalian reproduction. The present study was conducted to detect the sodium arsenite-induced oxidative stress and alterations in the structure and steroidogenesis in rat ovary. Twenty female adult rats were injected i.p. with sodium arsenite (8 mg/kg BW, T) or 0.9% saline (C) for 16 days. The oxidative stress indexes and morphology of the liver, kidney, and ovary were detected using commercial kits and HE staining, respectively. The serum progesterone and estradiol were detected by RIA, and the ovarian steroidogenic gene expressions were detected by real-time PCR. Results showed that the ovarian activities of SOD and GSH-PX decreased (P < 0.05), while the ROS activity and MDA level increased (P < 0.05) in the T group. HE staining results showed that treatment with sodium arsenite damaged the ovarian morphology, resulting in reduced large and medium follicles and increased atretic follicles. Nonetheless, neither the liver nor kidney showed evident changes in the oxidative stress indexes or morphology after sodium arsenite treatment. The serum progesterone and estradiol levels decreased (P < 0.05) with the reduced expressions in the ovarian steroidogenic genes (StAR, P450scc, and 3β-HSD) (P < 0.05). In conclusion, sodium arsenite injection can induce ovarian oxidative stress in rats which set up an appropriate model for future studies of ovarian diseases as well as the toxic mechanism of arsenic in the reproduction.

Involvement of metallothionein, homocysteine and B-vitamins in the attenuation of arsenic-induced uterine disorders in response to the oral application of hydro-ethanolic extract of Moringa oleifera seed: a preliminary study

The painful invasive chelation therapy makes it challenging to continue the prolonged treatment against arsenic toxicity. Hence, the significance of the present preliminary investigation was to explore a noninvasive treatment strategy against sodium arsenite (As³⁺) by the use of a hydroethanolic extract of Moringa oleifera (MO) seed. Arsenic treatment (10 mg/kg body-weight) in animals showed significant level of oxidative stress as evidenced by increased serum levels of malondialdehyde (MDA), conjugated dienes (CD) and reduced level of non-protein thiol (NPSH). A significant diminution in the activities of enzymatic antioxidants was noted in As³⁺-treated rats. As³⁺ treatment showed a lengthy phase of metestrous in animals followed by significantly diminished ovarian steroidogenesis, increased ovarian follicular degeneration and distortion of uterine tissue histomorphology. In addition, there was a significant depletion of Vitamin-B₉ (folate) and B₁₂ following As³⁺ ingestion. The levels of circulating TNF-α, homocysteine (Hcy), uterine-IL-6, and liver metallothionein (MT-1) were significantly elevated in arsenic treated rats. MO at a dose of 100 mg/kg body-weight could successfully mitigate the uterine ROS generation by maintaining the uterine antioxidant status in As³⁺- treated rats. This seed extract prevented the deterioration of As³⁺-mediated ovarian-steroidogenesis and ovarian and uterine histoarchitecture significantly. B₉ and B₁₂ levels were also improved following the ingestion of the MO extract in arsenicated animals. Elevation of Hcy, TNF-α and IL-6 was also prevented by this MO seed extract in As³⁺-treated rats. A further increase of MT-1 level was achieved after MO ingestion in As³⁺-treated rats. Here, the alleviation of arsenic toxicity might involve via the regulation of the components of S-adenosine methionine (SAM) pool and MT-1.

Restoration of uterine redox-balance by methanolic extract of Camellia sinensis in arsenicated rats

Arsenic, an environmental and industrial pollutant causes female reproductive disturbances and female infertility. Several researchers found that the use of Camellia sinensis (CS) (green tea) is effective as an alternative therapeutic strategy in the management of several health ailments. This study explores the role of CS extract against arsenic-induced rat uterine tissue damage. Methanolic extract of CS (10 mg/kg BW) was tested concomitantly in arsenic-treated (10 mg/kg BW) rats for a duration of two-oestrous cycle length (8 days). CS effectively attenuated arsenic-induced antioxidantdepletion and necrosis in uterine tissue. Rats treated with sodium arsenite showed significantlyreduced activities of enzymatic antioxidants like superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in uterine tissue as evidenced by the results of spectrophotometric and electrozymographic analysis. Co-administration of CS significantly reversed the above oxidative stress markers in uterine tissue along with the histopathological changes in ovarian and uterine tissue. Moreover, an increase in the level of transcription factor NF-κB in the uterine tissue in association with reduced serum levels of vitamin B12 and folic acid were mitigated in arsenic fed rats following CS co-administration.

Protective Effects of Curcumin against Sodium Arsenite-induced Ovarian Oxidative Injury in a Mouse Model

BACKGROUND

Excessive reactive oxygen species (ROS) may lead to a number of reproductive diseases such as polycystic ovary syndrome. This study aimed to establish an animal model of ovarian oxidative stress and to assess the protective effect of curcumin against oxidative injury.

METHODS

Ovarian oxidative stress was induced in female Kunming mice (n = 40) with intraperitoneal injection of 8 mg/kg sodium arsenite (As) once every other day for 16 days; meanwhile, they were, respectively, treated by intragastric administration of 0, 100, 150, or 200 mg/kg (n = 10/group) curcumin once per day for 21 days. Ten normal mice were used as control. Then, the mice were injected intraperitoneally with BrdU and sacrificed; the right ovaries were collected for hematoxylin and eosin (HE) staining and BrdU immunohistochemistry, and the left ovaries for enzyme-linked immunosorbent assay (ELISA) and Western blotting analyses.

RESULTS

The ELISA results showed that ROS (11.74 ± 0.65 IU/mg in 8 mg/kg AS + 0 mg/kg curcumin group vs. 10.71 ± 0.91 IU/mg in control group, P= 0.021) and malondialdehyde (MDA) (0.32 ± 0.02 nmol/g in 8 mg/kg AS + 0 mg/kg curcumin group vs. 0.27 ± 0.02 nmol/g in control group, P= 0.048) increased while superoxide dismutase (SOD) (3.96 ± 0.36 U/mg in 8 mg/kg AS + 0 mg/kg curcumin group vs. 4.51 ± 0.70 U/mg in control group, P= 0.012) and glutathione peroxidase (17.36 ± 1.63 U/g in 8 mg/kg AS + 0 mg/kg curcumin group vs. 18.92 ± 1.80 U/g in control group, P= 0.045) decreased in the ovary after injection of As, indicating successful modeling of oxidative stress. Curcumin treatment could considerably increase SOD (4.57 ± 0.68, 4.49 ± 0.27, and 4.56 ± 0.25 U/mg in 100 mg/kg, 150 mg/kg, and 200 mg/kg curcumin group, respectively, allP < 0.05) while significantly reduce ROS (10.64 ± 1.38, 10.73 ± 0.71, and 10.67 ± 1.38 IU/mg in 100 mg/kg, 150 mg/kg, and 200 mg/kg curcumin group, respectively, allP < 0.05) and MDA (0.28 ± 0.02, 0.25 ± 0.03, and 0.27 ± 0.04 nmol/g in 100 mg/kg, 150 mg/kg, and 200 mg/kg curcumin group, respectively; bothP < 0.05) in the ovary. HE staining and BrdU immunohistochemistry of the ovarian tissues indicated the increased amount of atretic follicles (5.67 ± 0.81, 5.84 ± 0.98, and 5.72 ± 0.84 in 100 mg/kg, 150 mg/kg, and 200 mg/kg curcumin group, respectively, all P < 0.05), and the inhibited proliferation of granular cells under oxidative stress would be reversed by curcumin. Furthermore, the Western blotting of ovarian tissues showed that the p66Shc expression upregulated under oxidative stress would be lowered by curcumin.

CONCLUSION

Curcumin could alleviate arsenic-induced ovarian oxidative injury to a certain extent.

Electrozymographic evaluation of the attenuation of arsenic induced degradation of hepatic SOD, catalase in an in vitro assay system by pectic polysaccharides of Momordica charantia in combination with curcumin

Momordica charantia (MC) fruit known as bitter gourd, is of potential nutritional and medicinal value. The objectives of the present in vitro study were to evaluate the efficacy of bioactive pectic polysaccharides (CCPS) of MC along with another well-known bioactive compound curcumin in the abrogation of hepatocellular oxidative stress persuaded by sodium arsenite. Electrozymographic method was developed for the assessment of superoxide dismutase (SOD) and catalase activities of liver tissues maintained under an in vitro system. A significant association of CCPS of MC in combination with curcumin was found in the alleviation of oxidative stress induced by sodium arsenite in liver slice. Generated data pointed out that CCPS of MC and curcumin separately or in combination can offer significant protection against alterations in malondialdehyde (MDA), conjugated diene (CD) and antioxidative defense (SOD, CAT) markers. Furthermore, results of hepatic cell DNA degradation strongly supported that both these co-administrations have efficacy in preventing cellular damage. This is the first information of extracted polysaccharides from MC preventing arsenic induced damage in a liver slice of rat.

Reproductive and Developmental Toxicity of Arsenic in Rodents: A Review

Arsenic is a recognized reproductive toxicant in humans and induces malformations, especially neural tube defects, in laboratory animals. Early studies showed that murine malformations occurred only when a high dose of inorganic arsenic was given by intravenous or intraperitoneal injection in early gestation. Oral gavage of inorganic arsenic at maternally toxic doses caused reduced fetal body weight and increased resorptions. Recently, arsenic reproductive and developmental toxicity has been studied in situations more similar to human exposures and using broader endpoints, such as behavioral changes and gene expression. For the general population, exposure to arsenic is mostly oral, particularly via drinking water, repeated and prolonged over time. In mice and rats, methylated or inorganic arsenic via drinking water or by repeated oral gavage induced male and female reproductive and developmental toxicities. Furthermore, at nonmaternally toxic levels, inorganic arsenic given to pregnant dams via drinking water affected fetal brain development and postnatal behaviors. However, arsenic given by repeated oral gavage to pregnant mice and rats was not morphologically teratogenic. In this review of arsenic reproductive and developmental toxicity in rats and mice, the authors summarize recent in vivo studies and discuss possible underlying mechanisms. The influences of folate, selenium, zinc, and arsenic methylation on arsenic reproductive and developmental toxicity are also discussed.

Mechanisms of arsenic disruption on gonadal, adrenal and thyroid endocrine systems in humans: A review

Due to its toxicity as a carcinogen and wide distribution in the environment, arsenic (As) exposure in humans is of public concern globally. Many studies have manifested that As exposure induces cancers besides pathological effects in humans. Animal studies showed that chronic As exposure induces serious neurological effects. Based on recent studies, researchers proposed that As, including arsenate (AsV) and arsenite (AsIII), is also an endocrine disruptor. This review discusses the mechanisms of As toxicity on three endocrine systems including gonadal, adrenal and thyroid endocrine systems. Arsenic methylation and oxidative stress are responsible for As-induced disorders of endocrine systems, however, strong binding of AsIII to thiols also play an important role. Some studies showed AsV toxicity on endocrine systems, but mechanistic investigation is lacking. Research is needed to look into their toxicity mechanisms to help cure the illnesses caused by As-induced endocrine system disorders.

Curcumin Inhibits The Adverse Effects of Sodium Arsenite in Mouse Epididymal Sperm

Background

The aim of this study was to investigate the effects of curcumin on epididy- mal sperm parameters in adult male Navel Medical Research Institute (NMRI) mice ex- posed to sodium arsenite.

Materials and Methods

In this experimental study, we divided the animals into four groups: control, sodium arsenite (5 mg/kg), curcumin (100 mg/kg) and curcumin+sodium arsenite. Exposures were performed by intraperitoneal injections for a 5-week period. After the exposure period, we recorded the animals’ body and left testes weights. The left caudal epididymis was used to count the sperm number and analyze motility, viability, morphological abnormalities, acrosome reaction, DNA integrity, and histone-protamine replacement in the spermatozoa. One-way analysis of variance (ANOVA) followed by the Tukey’s test was used to assess the statistical significance of the data with SPSS 16.0. P<0.05 was considered significant.

Results

Mice exposed to sodium arsenite showed a significant decrease in the num- ber, motility, viability, normal sperm morphology and acrosome integrity of spermato- zoa compared to the control group. In the curcumin+sodium arsenite group, curcumin significantly reversed these adverse effects to the point where they approximated the control. In addition, the application of curcumin alone had no significant difference in these parameters compared to the control and curcumin+sodium arsenite groups. However, we observed no significant differences in the body and the testis weight as well as the DNA integrity and histone-protamine replacement in the spermatozoa of the four groups.

Conclusion

Curcumin compensated for the toxic effects of sodium arsenite on a number of sperm parameters in adult mice.

Acute Sodium Arsenite-Induced Hematological and Biochemical Changes in Wistar Rats: Protective Effects of Ethanol Extract of Ageratum conyzoides

Background:

Ageratum conyzoides L. (Asteraceae) is an annual herbaceous plant used in folklore medicine for the treatment of a wide range of diseases.

Objective:

To investigate the protective effect of the ethanol leaf extract of A. conyzoides (EEAC) against hematological, serum biochemical and histological alterations induced by Sodium arsenite administration to Wistar rats.

Materials and Methods:

Twenty male Wistar rats were randomly assigned into four groups of five rats each. Group I received propylene glycol and Group II rats were given the (EEAC, 100 mg/kg b.w.) orally for 7 days. Group III were given a single oral dose of sodium arsenite (NaAsO₂, 2.5 mg/kg b.w.). Animals in Group IV were pretreated with 100 mg/kg EEAC for 7 days followed by a single oral dose of sodium arsenite.

Results:

Arsenic exposure resulted in significant reductions (P < 0.05) in values of packed cell volume (PCV), hemoglobin concentration (Hb) and red blood cell (RBC) count, and elevation in total white blood cell (WBC) count with insignificant reductions in serum total protein, albumin, and globulin levels. Alterations in aspartate aminotransferase, alanine transferase, alkaline phosphatase, and gamma glutamyl transferase activities, as well as in serum levels of urea, creatinine, glucose, cholesterol, and triglyceride levels, were not statistically significant. EEAC significantly restored (P < 0.05) the PCV, Hb, RBC, and WBC as well as serum albumin, globulin, and total protein to normal values.

Conclusion:

The results of this study indicate that EEAC possess strong potentials to protect against toxicities induced by sodium arsenite.

SUMMARY

Ageratum conyzoides produced significant reversal of the reduction in the erythrocytic indices (packed cell volume, red blood cell, and Hb) caused by sodium arsenite

Sodium arsenite-induced slight elevations in serum aspartate aminotransferase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP), correlating with the histopathological lesions observed

Ageratum conyzoides produced only slight reductions in AST, ALT, and ALP compared to the sodium arsenite group, but significantly reduced the severity of histopathological lesions.

Abbreviations Used: EEAC: Ethanol extract of Ageratum conyzoides; RBC: Red blood cell; WBC: White blood cell; Hb: Hemoglobin; ALT: Alanine transaminase; AST: Aspartate transaminase or Aspartate aminotransferase; ALP: Alkaline phosphatase; GGT: Gamma glutamyl transferase.

A review on exposure and effects of arsenic in passerine birds

Arsenic (As) is a metalloid of high concern because of its toxic effects for plants and animals. However, it is hard to find information on this metalloid in passerines. This review presents a comprehensive overview of As exposure and effects in birds, and more particularly in passerines, as a result of an extensive search of the literature available. Internal tissues are the most frequently analyzed matrices for As determination in passerines (37.5% of the reviewed studies used internal tissues), followed by feathers and eggs (32.5% each), feces (27.5%), and finally blood (15%). A clear tendency is found in recent years to the use of non-destructive samples. Most studies on As concentrations in passerines have been done in great tit (Parus major; 50%), followed by pied flycatcher (Ficedula hypoleuca; 22.5%). Some factors such as diet and migratory status are crucial on the interspecific differences in As exposure. More studies are needed to elucidate if intraspecific factors like age or gender affect As concentrations in different tissues. The literature review shows that studies on As concentrations in passerines have been done mainly in the United States (30%), followed by Belgium (22.5%), and Finland (20%), making evident the scarce or even lack of information in some countries, so we recommend further research in order to overcome the data gap, particularly in the southern hemisphere. Studies on humans, laboratory animals and birds have found a wide range of effects on different organ systems when they are exposed to different forms of As. This review shows that few field studies on As exposure and effects in passerines have been done, and all of them are correlative so far. Arsenic manipulation experiments on passerines are recommended to explore the adverse effects of As in free-living populations at similar levels to those occurring in the environment.

CAPSULE

This review summarizes the most interesting published studies on As exposure and effects in passerines.

Acute arsenic treatment alters arachidonic acid and its associated metabolite levels in the brain of C57Bl/6 mice

The toxic effects of arsenic on the whole brain, as well as the discrete regions, has been previously reported for mice. We investigated the effects of acute arsenite (As(III)) on brain levels of arachidonic acid (AA) and its associated metabolites generated through cytochrome P450 (CYP), cyclooxygenase (COX), and lipoxygenase (LOX) pathways. Our results demonstrated that acute As(III) treatment (12.5 mg·(kg body mass)−1) decreases cytosolic phospholipase A2 (cPLA2) with a subsequent decrease in its catalytic activity and brain AA levels. In addition, As(III) differentially altered CYP epoxygenases and CYP ω-hydroxylases, but it did not affect brain Ephx2 mRNA or sEH catalytic activity levels. As(III)-mediated effects on Cyps caused an increase in brain 5,6-epoxyeicosatrienoic acid (5,6-EET) and 16/17-hydroxyeicosatetreinoic acid (16/17-HETE) levels, and a decrease in 18- and 20-HETE levels. Furthermore, As(III) increased cyclooxygenase-2 (COX-2) mRNA while decreasing prostaglandins F2α (PGF2α) and PGJ2. As(III) also increased brain 5-lipoxygenase (5-LOX) and 15-LOX mRNA, but decreased 12-LOX mRNA. These changes in LOX mRNA were associated with a decrease in 8/12-HETE levels only. In conclusion, this is the first demonstration that As(III) decreases AA levels coinciding with alterations to EET, HETE, and PG levels, which affects brain development and neurochemistry.

Histological and histometrical study of the protective role of α-tocopherol against sodium arsenite toxicity in rat ovaries

This study examines histometrical changes induced by sodium arsenite (SA), as an environmental pollutant, and investigates the protective effect of α-tocopherol on ovaries of SA-treated rats during the prenatal stage until sexual maturity. Rats were classified into groups: control, SA (8 ppm/day), α-tocopherol (100 ppm/day), and SA+α-tocopherol. Treatment was performed from pregnancy until maturation when the rats and ovaries were weighed. The Cavalieri method was used to estimate volume of the ovaries, cortex, medulla, and corpus luteum. The mean diameter of oocytes, granulosa cells, and nuclei were measured and volume was estimated using the Nucleator method. The number of oocytes and thickness of the zona pellucida (ZP) were determined using an optical dissector and orthogonal intercept method, respectively. SA reduced the body and ovary weight, the number of secondary, antral and Graafian oocytes, volume of the ovaries, cortex, medulla and corpus luteum, mean diameter and volume of oocytes in primordial and primary follicles, mean diameter and volume of oocyte nuclei in all types of follicles, and mean thickness of the ZP in secondary and antral follicles. Also, the mean diameter and volume of granulosa cells and their nuclei in antral and Graafian follicles decreased significantly. Vacuolization and vascular congestion in the corpus luteum and an increase in the number of atretic oocytes were seen in the SA group. Most of these parameters were unchanged from the control level in the SA+α-tocopherol group. It was concluded that α-tocopherol supplementation reduced the toxic effects of SA exposure on ovarian tissue in rats.

Prepubertal exposure to arsenic(III) suppresses circulating insulin-like growth factor-1 (IGF-1) delaying sexual maturation in female rats

Arsenic (As) is a prevalent environmental toxin readily accessible for human consumption and has been identified as an endocrine disruptor. However, it is not known what impact As has on female sexual maturation. Therefore, in the present study, we investigated the effects of prepubertal exposure on mammary gland development and pubertal onset in female rats. Results showed that prepubertal exposure to 10 mg/kg of arsenite (As(III)) delayed vaginal opening (VO) and prepubertal mammary gland maturation. We determined that As accumulates in the liver, disrupts hepatocyte function and suppresses serum levels of the puberty related hormone insulin-like growth factor 1 (IGF-1) in prepubertal animals. Overall, this is the first study to show that prepubertal exposure to As(III) acts peripherally to suppress circulating levels of IGF-1 resulting in delayed sexual maturation. Furthermore, this study identifies a critical window of increased susceptibility to As(III) that may have a lasting impact on female reproductive function.

Protective effect of Juglans nigra on sodium arsenite-induced toxicity in rats

BACKGROUND

Consumption of arsenic contaminated water has been implicated in metalloid-induced carcinogenesis. Dietary intake of certain plant products with chemoprotective properties may protect against the onset of diseases and promote maintenance of health.

OBJECTIVES

We investigated the outcome of black walnut Juglans nigra (JN) consumption on sodium arsenite (SA)-induced toxicity in rats.

MATERIALS AND METHODS

WISTER ALBINO RATS WERE TREATED AS FOLLOWS: Control, SA only (positive control) (2.5 mg/kg body weight), JN only (100 mg/kg weight), and JN+SA coadministered. After 5 weeks animals were sacrificed whole blood, femur, liver and testis harvested were assessed for hepatic transaminases and clastogenicity. Histology of the liver, sperm morphology and quality were also assessed. Data were analyzed (ANOVA) and expressed as means ±SD.

RESULTS

SA treatment elevated hepatic transaminases level in serum (P < 0.05), induced histological changes in liver: fibroplasia and periportal hepatocytes infiltration by mononuclear cells. These changes were ameliorated by JN (P < 0.05) coadministration. SA induced micronuclei formation (P < 0.05). Again JN decreased (P < 0.05) micronuclei formation by 50%. Sperm count and motility decreased (P < 0.05) in all groups compared to control.

CONCLUSION

JN showed no protection against arsenite effect on sperm quality. Hepatoprotective and anticlastogenic effects were apparent suggesting a chemopreventive potential active against arsenite genotoxicity and chromosomal instability which have implication for metalloid-induced carcinogenesis.

Characterization of arsenic-induced cytotoxicity in liver with stress in erythrocytes and its reversibility with Pleurotus florida lectin

Arsenic is one of the most hazardous substances in the environment known to cause toxicity in multiple organs. Cell adhesion, morphological alterations, cell proliferation, terminal deoxyuridine triphosphate nick-end labeling (TUNEL) and caspase-3/CPP32 fluorometric protease assay were important biomarkers to assess apoptosis in cells. This study aimed to evaluate arsenic-induced apoptosis in the hepatocytes of rat and its protective efficacy with coadministration of ascorbic acid (AA) and Pleurotus florida lectin (PFL) individually. Results of the present study also showed that arsenic caused cytotoxicity by elevating morphological alterations, TUNEL-positive nuclei, caspase-3 activity and DNA damage and reducing cell adhesion and cell proliferation in a time-dependent manner. The apoptosis in hepatocytes was reverted to normal value after coadministration of mushroom lectin in arsenic-exposed rat. The study provided significant evidence that PFL has antiapoptotic property against arsenic-induced toxicity. The beneficial effect of PFL was proportional to its duration of exposure. Retard activities of superoxide dismutase and catalase, enhanced lipid peroxidation as well as protein carbonyl in erythrocytes caused by arsenic could also be maintained toward normalcy by supplementation of AA and PFL. These antioxidative effects were exhibited in a time-dependant manner. In rat, treatment with AA and PFL prevented alteration of plasma enzyme activities caused by arsenic. The results concluded that treatment with PFL has significant role in protecting animals from arsenic-induced erythrocytic damage. This finding might be of therapeutic benefit in people suffering from chronic exposure to arsenic from natural sources, a global problem especially relevant to millions of people on the Indian subcontinent.

Lipid peroxidation in brain tissue following administration of low and high doses of arsenite and L-ascorbate in wistar strain rats

This study aimed at investigating the mechanism by which sodium arsenite induces brain injury and the role of L-ascorbate. Thirty adult (n=5) Wistar rats weighing between 140 and 160 g were used. Group 1 neither received sodium arsenite nor L-ascorbate (control), group 2 was administered low dose of arsenite only, group 3 received high dose of arsenite only, group 4 was administered L-ascorbate only, group 5 was administered low dose of arsenite and L-ascorbate, and group 6 received high dose of arsenite and L-ascorbate. M0 alon dialdehyde, MDA, levels were significantly increased in rats treated with high dose of arsenite when compared with those treated with low dose of arsenite. However, all treated groups except those treated with L-ascorbate only showed significant increase in MDA levels when compared with the control group. Rats treated with high dose of arsenite and L-ascorbate showed a significantly higher MDA level than those treated with low dose of arsenite and L-ascorbate. However, catalase activity, body weight gain, brain weight and mean food consumption were comparable across all groups. Brain tissue total protein was similar in all groups except in both groups treated with high dose of arsenite, where they were significantly reduced when compared with the control group. I0 n conclusion, sodium arsenite treatment induces brain injury via a mechanism associated with lipid peroxidation, but not catalase-dependent. However, L-ascorbate ameliorates arsenite-induced oxidative injury in the brain. L-ascorbate antioxidative potential in alleviating arsenite-induced brain injury is dependent on the concentration of arsenite.

Co-administration of sodium arsenite and ethanol: Protection by aqueous extract of Aframomum longiscapum seeds

Background:

Human exposure to arsenicals, its toxicity, subsequent adverse effects on health has been widely reported and implicated in the etiology of several cancers.

Objectives:

We investigated the effect of Aframomum longiscapum (AL) extracts on sodium arsenite (SA) and ethanol (EtOH)-induced toxicities in rats.

Materials and Methods:

Male rats were fed SA, EtOH, and SA + EtOH, with or without AL for 5 weeks. Hepatic transaminases were assessed in serum, micronucleated polychromatic erythrocytes (mPCEs) from bone marrow, liver histopathology, and semen quality from caudal epididymis were assessed, respectively, and data were represented as mean ± SD, analyzed by ANOVA.

Results:

SA, SA + EtOH, and AL alone induced mPCEs formation in rat bone marrow (P < 0.05). A decrease (P < 0.05) in mPCEs in AL + SA + EtOH-treated rats compared with SA, and SA + EtOH was observed. SA and EtOH treatment increased serum hepatic transaminases (P < 0.05) relative to control, while AL treatment resulted in a decrease (P < 0.05). AL, SA, and SA + EtOH treatment decreased sperm count and motility (P < 0.05) with no effect on viability compared with control. Semen morphological abnormalities showed no difference (P > 0.05) across the treated groups. Hepatic histopathology indicated mild mononuclear cellular infiltration in the control group. Necrotic hepatocyte were observed in SA, SA + EtOH treated groups, with no visible lesions seen in the AL treated group. Mild hepatocyte congestion of the portal vessels was observed in AL + SA + EtOH-treated groups.

Conclusion:

The AL extract exhibited anticlastogenic and hepatoprotective potentials, reduced sperm count, motility, with no effect on viability and morphology. Our findings suggest that AL may mitigate the effect of arsenicals-induced clastogenicity implicated in chemical carcinogenesis.

Effect of Pleurotus florida lectin (PFL) on arsenic-induced activities of splenocytes in rat

The present study was undertaken to investigate the protective effect of Pleurotus florida lectin (PFL) against arsenic-induced cytotoxicity and oxidative damages in freshly isolated splenocytes of rodents. Our finding indicated that arsenic caused reduction in cell adhesion, morphological alterations, cell proliferation, nitro blue tetrazolium (NBT) index, superoxide dismutase (SOD) activity, catalase (CAT) activity and relative mRNA expression of SOD2 in relation to housekeeping gene glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and increased production of nitric oxide (NO), protein carbonyl (PC) and lipid peroxidation levels (LPO) assembled to play key factors for cytotoxicity and oxidative stress. PFL normalized cellular damages and enhanced SOD production pathway relating to gene expression. Further studies are needed to address effective phytochemicals of the edible mushroom and their mechanism.

Hepatoprotective role of vitamin B(12) and folic acid in arsenic intoxicated rats

The present study elucidated the protective role of vitamin B(12) with folic acid against arsenic-induced hepatotoxicity in female rats. Ingestion of sodium-arsenite- contaminated water [0.4 ppm/100 g body weight (b.w.)/day] in combination with vitamin B(12) plus folic acid (0.07 and 4.0 μg, respectively/100 g b.w./day) for 24 days to Wistar rats offered a significant protection against alone arsenic-induced distorted liver function, damaged histoarchitecture, elevated oxidative stress, and DNA fragmentation of hepatic tissues. Arsenic only exposure decreased hepatic superoxide dismutase (SOD), catalase activities, and the level of nonprotein-soluble thiol (NPSH), with a concomitant increase in thiobarbituric acid reactive substances (TBARS) and conjugated dienes (CDs) in the liver. Vitamin supplementation restrained the increase of TBARS and CDs by restoring catalase, SOD, and NPSH levels. Restricted generation of free radicals may be correlated to the protection of DNA stability and hepatic morphology. This study explains the decisive role of vitamin B(12) with folic acid to ameliorate arsenic-mediated liver injuries.

Protective role of Moringa oleifera (Sajina) seed on arsenic-induced hepatocellular degeneration in female albino rats

In an attempt to develop new herbal therapy, an aqueous extract of the seed of Moringa oleifera was used to screen the effect on arsenic-induced hepatic toxicity in female rat of Wistar strain. Subchronic exposure to sodium arsenite (0.4 ppm/100 g body weight/day via drinking water for a period of 24 days) significantly increased activities of hepatic and lipid function markers such as alanine transaminase, aspartate transaminase, cholesterol, triglycerides, LDL along with a decrease in total protein and HDL. A notable distortion of hepatocellular histoarchitecture was prominent with a concomitant increase in DNA fragmentation following arsenic exposure. A marked elevation of lipid peroxidation in hepatic tissue was also evident from the hepatic accumulation of malondialdehyde and conjugated dienes along with suppressed activities in the antioxidant enzymes such as superoxide dismutase and catalase. However, co-administration of aqueous seed extract of M. oleifera (500 mg/100 g body weight/day for a period of 24 days) was found to significantly prevent the arsenic-induced alteration of hepatic function markers and lipid profile. Moreover, the degeneration of histoarchitecture of liver found in arsenic-treated rats was protected along with partial but definite prevention against DNA fragmentation induction. Similarly, generation of reactive oxygen species and free radicals were found to be significantly less along with restored activities of antioxidant enzymes in M. oleifera co-administered group with comparison to arsenic alone treatment group. The present investigation offers strong evidence for the hepato-protective and antioxidative efficiencies of M. oleifera seed extract against oxidative stress induced by arsenic.

Arsenic: toxicity, oxidative stress and human disease

Arsenic (As) is a toxic metalloid element that is present in air, water and soil. Inorganic arsenic tends to be more toxic than organic arsenic. Examples of methylated organic arsenicals include monomethylarsonic acid [MMA(V)] and dimethylarsinic acid [DMA(V)]. Reactive oxygen species (ROS)-mediated oxidative damage is a common denominator in arsenic pathogenesis. In addition, arsenic induces morphological changes in the integrity of mitochondria. Cascade mechanisms of free radical formation derived from the superoxide radical, combined with glutathione-depleting agents, increase the sensitivity of cells to arsenic toxicity. When both humans and animals are exposed to arsenic, they experience an increased formation of ROS/RNS, including peroxyl radicals (ROO•), the superoxide radical, singlet oxygen, hydroxyl radical (OH•) via the Fenton reaction, hydrogen peroxide, the dimethylarsenic radical, the dimethylarsenic peroxyl radical and/or oxidant-induced DNA damage. Arsenic induces the formation of oxidized lipids which in turn generate several bioactive molecules (ROS, peroxides and isoprostanes), of which aldehydes [malondialdehyde (MDA) and 4-hydroxy-nonenal (HNE)] are the major end products. This review discusses aspects of chronic and acute exposures of arsenic in the etiology of cancer, cardiovascular disease (hypertension and atherosclerosis), neurological disorders, gastrointestinal disturbances, liver disease and renal disease, reproductive health effects, dermal changes and other health disorders. The role of antioxidant defence systems against arsenic toxicity is also discussed. Consideration is given to the role of vitamin C (ascorbic acid), vitamin E (α-tocopherol), curcumin, glutathione and antioxidant enzymes such as superoxide dismutase, catalase and glutathione peroxidase in their protective roles against arsenic-induced oxidative stress.

Arsenic abrogates the estrogen-signaling pathway in the rat uterus

BACKGROUND

Arsenic, a major pollutant of water as well as soil, is a known endocrine disruptor, and shows adverse effects on the female reproductive physiology. However, the exact molecular events leading to reproductive dysfunctions as a result of arsenic exposure are yet to be ascertained. This report evaluates the effect and mode of action of chronic oral arsenic exposure on the uterine physiology of mature female albino rats.

METHODS

The effect of chronic oral exposure to arsenic at the dose of 4 microg/ml for 28 days was evaluated on adult female albino rats. Hematoxylin-eosin double staining method evaluated the changes in the histological architecture of the uterus. Circulating levels of gonadotropins and estradiol were assayed by enzyme-linked immunosorbent assay. Expression of the estrogen receptor and estrogen-induced genes was studied at the mRNA level by RT-PCR and at the protein level by immunohistochemistry and western blot analysis.

RESULTS

Sodium arsenite treatment decreased circulating levels of estradiol in a dose and time-dependent manner, along with decrease in the levels of both LH and FSH. Histological evaluation revealed degeneration of luminal epithelial cells and endometrial glands in response to arsenic treatment, along with reduction in thickness of the longitudinal muscle layer. Concomitantly, downregulation of estrogen receptor (ER alpha), the estrogen-responsive gene - vascular endothelial growth factor (VEGF), and G1 cell cycle proteins, cyclin D1 and CDK4, was also observed.

CONCLUSION

Together, the results indicate that arsenic disrupted the circulating levels of gonadotropins and estradiol, led to degeneration of luminal epithelial, stromal and myometrial cells of the rat uterus and downregulated the downstream components of the estrogen signaling pathway. Since development and functional maintenance of the uterus is under the influence of estradiol, arsenic-induced structural degeneration may be attributed to the reduction in circulating estradiol levels. Downregulation of the estrogen receptor and estrogen-responsive genes in response to arsenic indicates a mechanism of suppression of female reproductive functions by an environmental toxicant that is contra-mechanistic to that of estrogen.

The involvement of hypophyseal-gonadal and hypophyseal-adrenal axes in arsenic-mediated ovarian and uterine toxicity: modulation by hCG

This study evaluated the involvement of hypophyseal-gonadal and hypophyseal-adrenal axes as a possible mechanism of sodium arsenite toxicity in ovary and uterus by the coadministration of hCG. Subchronic treatment of 0.4 ppm of sodium arsenite/(100 g body weight day) via drinking water for seven estrous cycles significantly suppressed the plasma levels of leutinizing hormone, follicle-stimulating hormone, and estradiol along with sluggish ovarian activities of Delta(5),3beta-hydroxysteroid dehydrogenase and 17beta-hydroxysteroid dehydrogenase followed by a reduction in gonadal tissue peroxidase activities in mature female rats at diestrous phase. Noticeable weight loss of the ovary and uterus along with prolonged diestrous phase and increased deposition of arsenic in the plasma and in these reproductive organs were also demonstrated following the ingestion of arsenic. Follicular atresia and thinning of the uterine luminal diameter were evident after sodium arsenite treatment. Effective protection of gonadal weight loss, suppressed ovarian steroidogenesis, and altered ovarian and uterine peroxidase activities were noticed when 1.0 IU hCG/(100 g body weight day) is given in arsenic-intoxicated rats. Normal estrous cyclicity was restored toward the control level after hCG coadministration, though the elimination of elementary arsenic from the plasma and gonadal tissues was impossible. A significant recovery in the restoration of ovarian and uterine histoarchitecture was prominent after hCG treatment. Adrenal hypertrophy and steroidogenic arrest of the adrenal gland along with altered level of brain monoamines in the midbrain and diencephalons following arsenic intoxication were also ameliorated after hCG coadministration.

Supplementation of ascorbic acid prevents oxidative damages in arsenic-loaded hepatic tissue of rat: An ex vivo study

Oxidative stress due to arsenic toxicity and ameliorative potentiality of L-ascorbic acid was evaluated in an ex vivo system of rat hepatic tissue. The study revealed that arsenic increased the activity of superoxide dismutase (SOD) and catalase (CAT) and the level of lipid peroxidation (LPO), protein carbonyl (PC) and nitric oxide (NO) at 1 hour, 1.5 hours and 2 hours of incubation. Co-treatment with L-ascorbic acid was found effective to normalize the activity of SOD and CAT and the production of LPO, PC and NO in hepatic tissue. This ex vivo study suggested that ascorbic acid is helpful to ameliorate arsenic-induced oxidative stress. This may be one of the alternative screening systems to study the efficacy of antioxidant and hepatoprotective agent.

L-Ascorbate protects rat hepatocytes against sodium arsenite--induced cytotoxicity and oxidative damage

Sodium arsenite-exposed hepatocytes of rat showed higher production of nitric oxide (NO) and increased lipid peroxidation (LPO) level vis-a-vis activity of superoxide dismutase (SOD) and catalase (CAT) were significantly lowered. Subsequently, the cell proliferation index (CPI) and cell viability were also reduced. Treatment with L-ascorbate was found effective in normalizing the arsenic-induced alteration of SOD and CAT activity and LPO level in rat hepatocytes. These observations indicated that L-ascorbate also has potent cytoprotective role as it could reduce the NO production and normalize the cell proliferation and viability of hepatocytes. Therefore, the in vitro study suggested that ascorbic acid is helpful to ameliorate the arsenic-induced cytotoxicity and oxidative stress of rat hepatocytes.

Intracellular redox imbalance and extracellular amino acid metabolic abnormality contribute to arsenic-induced developmental retardation in mouse preimplantation embryos

Inorganic arsenic, an environmental contaminant, is known to cause cancer, developmental retardation, and many other serious diseases. Previous researches have shown that arsenic exerts its toxicity partially through generating reactive oxygen species (ROS). However, it is still not well understood how ROS links arsenic exposure to developmental retardation of preimplantation embryo. Here we demonstrate that high-level arsenite induces severe redox imbalance by decreasing the levels of glutathione and increasing the levels of ROS through the oxidative stress adaptor p66Shc, which induces apoptosis by activating the cytochrome c-caspase. In addition, low-level arsenite seriously perturbs the metabolism of extracellular amino acid, especially that of the cytotoxic and antioxidative amino acids in preimplantation embryos, may also be the reason for developmental delay. Furthermore, an antioxidant, N-acetyl-L-cysteine, improves the development of arsenite-exposed embryos by reducing intracellular ROS and adjusting amino acid metabolism, suggesting that increasing the intracellular antioxidant level may have preventive or therapeutic effects on arsenic-induced embryonic toxicity. In conclusion, we suggest that p66Shc-linked redox imbalance and abnormal extracellular amino acid metabolism mediate arsenite-induced embryonic retardation.

The steroidogenic acute regulatory protein as a target of endocrine disruption in male reproduction

Development of the adult male reproductive tract requires proper spatial-temporal expression of the sex hormones testosterone and estrogen during fetal developmental stages and at puberty. Exogenous agents that disrupt the production and/or actions of the testosterone and estrogen and cause aberrant reproductive tract development can be thought of as endocrine disruptors (ED). This review will focus on the impact of ED on testosterone production by Leydig cells during fetal development and in the adult. In particular, the genes encoding the steroidogenic acute regulatory protein (StAR) and cytochrome P450 17 alpha hydroxylase/17,20 lyase (CYP17A1) within the steroid hormone biosynthetic pathway are highlighted as ED targets. We begin with an overview of steroidogenesis and regulation of StAR then summarize the published literature on the effects of diethylstibesterol, phthalate esters, and arsenite on male reproduction with a focus on the expression and function of StAR.

Effect of L-ascorbic acid supplementation on testicular oxidative stress and endocrine disorders in mature male rats exposed to intensive swimming exercise

In order to investigate the ameliorative potential of L-ascorbic acid on intensive swimming exercise induced testicular oxidative stress, 18 Wistar male rats (age: 3 months, weight: 127.5 ± 5.3 g) were randomly divided into the following groups: (i) control group (CG, n = 6); (ii) experimental group (EG, n = 6); and (iii) supplemented group (SG, n = 6). An exercise protocol of 3 h swimming per day, five days per week was followed for 6 weeks in EG and SG with no exercise in CG. In SG, L-ascorbic acid was supplied orally at a dose of 25-mg/kg of bodyweight each day for 6 weeks. A significant decrease (P < 0.05) was noted in paired testicular weights, epididymal sperm count, testicular Δ⁵, 3β-hydroxyseroid dehydrogenase, 17β-hydroxyseroid dehydrogenase, plasma levels of testosterone luteinizing hormone, follicle stimulating hormone, prolactin, the numbers of preleptotine spermatocytes, midpachytene spermatocytes and stage 7 spermatids of stage VII seminiferous epithelium cycle in EG when compared with CG. A significant elevation (P < 0.05) in plasma corticosterone and testicular content of malondialdehyde along with a significant reduction (P < 0.05) in glutathione, ascorbic acid, α-tocopherol, superoxide dismutase, catalase and glutathione-peroxidase, and glutathione-S-transferase were noted in testes of EG compared with CG. No significant change was noted in final bodyweight or numbers of spermatogonia-A among the groups. Furthermore, L-ascorbic acid supplementation restored the above parameters to the control level. Conclusion:  It can be concluded that intensive swimming exercise induced oxidative stress causes dysfunctions in the male reproductive system, which can be protected by L-ascorbic acid. (Reprod Med Biol 2006; 5: 145-153).