Regulation of Nrf2 signaling factor in cadmium combined with bacitracin induced endoplasmic reticulum stress in testes and ovaries of rats / 中国职业医学

@#Objective To investigate the effect of acute exposure to cadmium combined with bacitracin on the endoplasmic reticulum stress (ERS) in testes and ovaries of rats and its regulation by nuclear factor erythroid-2-related factor 2 (Nrf2). Methods According to the 4×2 factorial design model, 48 specific pathogen free adult SD rats were divided into four groups: the control group and the low-, medium- and high- dose cadmium chloride exposure groups. Each group was further divided into with- or without bacitracin combined subgroup. There were six rats in each subgroup with 3 males and 3 females. The low-, medium- and high- dose groups were intraperitoneally injected with 5, 10, 20 mg/kg body weight of cadmium chloride solution, respectively. The control group was intraperitoneally injected with the same amount of 0.9% sodium chloride solution. Among them, rats in the bacitracin combined subgroup were given a one-time intraperitoneal injection of bacitracin at a dose of 20 mg/kg body weight two hours before cadmium chloride exposure. After 48 hours, the rats were sacrificed. The mRNA expression of glucose regulated protein78 kD (Grp78), protein kinase R-like endoplasmic reticulum kinase (Perk), Nrf2 in testes and ovaries of rats was determined using quantitative real-time polymerase chain reaction. The protein expression of GRP78, PERK, NRF2 was determined using Western blotting. Results The mRNA expression of Grp78, Perk, Nrf2 and the protein expression of GRP78, PERK, NRF2 in testes and ovaries of rats in the no bacitracin combined subgroups of the three dose groups showed different degrees of up-regulated changes compared with the no bacitracin combined subgroup of the control group (all P<0.05). Among them, the expression of the three kinds of mRNAs and proteins in the testes and ovaries of rats in the no bacitracin combined subgroups of the high-dose group was up-regulated (all P<0.05), and most of them were higher than those in the no bacitracin combined subgroups of the low- and medium-dose groups (all P<0.05). The expression of most of the three kinds of mRNAs and proteins in testes of rats showed different degrees of down-regulated changes (all P<0.05), but the expression of the three kinds of mRNAs and proteins showed different degrees of up-regulated changes in ovaries (all P<0.05) in the bacitracin combined subgroups of the three doses groups than that in the bacitracin combined subgroups of the control group, and especially in the bacitracin combined subgroups of the high-dose subgroup. The expression of the three kinds of mRNAs and proteins in testes and ovaries of rats in the bacitracin combined subgroups of the three doses groups showed different degrees of changes (all P<0.05) compared with the no bacitracin combined subgroup in the same group, and the expression in the bacitracin combined subgroups of the medium- and high-dose groups showed mainly down-regulated changes (all P<0.05). Conclusion Acute exposure to cadmium can induce different degrees of ERS, activate PERK/NRF2 signaling pathway, and improve the toxicity to testis and ovary. Bacitracin can inhibit cadmium-induced ERS, thereby inhibiting the activation of PERK/NRF2 signaling pathway, and enhancing the synergistic effect of cadmium on testis and ovary toxicity. The higher the exposure dose of cadmium, the more obvious the inhibitory effect.

Modulatory effect of Turnera diffusa against testicular toxicity induced by fenitrothion and/or hexavalent chromium in rats.

Oxidative stress and increased production of reactive oxygen species have been implicated in pesticides and heavy metals toxicity. The objective of this study was to investigate the efficacy of Turnera diffusa Willd (damiana) on counteracting fenitrothion (FNT) and/or potassium dichromate (CrVI)-induced testicular toxicity and oxidative injury in rats. FNT and/or CrVI intoxicated animals revealed a significant increase in thiobarbituric acid reactive substances and hydrogen peroxide levels. While, reduced glutathione and protein content, as well as antioxidant enzymes, phosphatases, and aminotransferases activities, were significantly decreased. In addition, significant changes in testosterone and follicle-stimulating hormone levels were detected. Furthermore, histological and immunohistochemical alterations were observed in rat testes and this supported the observed biochemical changes. On the other hand, rats treated with damiana alone decreased lipid peroxidation and increased most of the examined parameters. Moreover, damiana pretreatment to FNT and/or CrVI-intoxicated rats showed significant improvement in lipid peroxidation, enzyme activities, and hormones as compared with their respective treated groups. Conclusively, rats treated with both FNT and/or CrVI showed pronounced hazardous effect especially in their combination group in addition, Turnera diffusa had a potential protective role against FNT and/or CrVI induced testicular toxicity.

Effects of telmisartan and losartan on irradiated testes.

AIMS: To analyze the effects of radiation on the reproductive tissue of male Wistar rats and to evaluate whether treatment with the Ang II AT1 receptor antagonists telmisartan and losartan mitigate the dysfunctions resulting from this exposure. MAIN METHODS: Rats were randomly divided into groups: Control, Irradiated, Telmisartan, Losartan, Irradiated+Telmisartan, and Irradiated+Losartan. Single dose of 5Gy was administered directly into the scrotum, followed by treatment with telmisartan (12mg/kg/day) or losartan (34mg/kg/two times/day) for 60days. Testicular function parameters were evaluated from spermatozoa of the vas deferens. Testes were processed for histopathological and morphometric-stereological analysis. Proliferating cell nuclear antigen (PCNA) immunohistochemistry was evaluated. KEY FINDINGS: Radiation significantly reduced sperm motility, concentration, vitality, and increased the number of abnormal spermatozoa. Telmisartan and losartan did not significantly prevent these radiation-induced disorders. Seminiferous tubules were atrophied in both untreated and treated irradiated testes, and exhibited vacuoles, increased interstitial tissue and high number of blood vessels. However, several seminiferous tubules in recuperation were founded among damaged tubules in the testes of treated animals. The PCNA immunohistochemistry confirmed these outcomes. PCNA-positive cells were detected in dividing spermatogonia and spermatocytes from irradiated telmisartan and losartan treated rats whereas in the only-irradiated group, PCNA staining was observed in the nuclei of only the surviving spermatogonia. SIGNIFICANCE: Under these experimental conditions, the testicular function parameters showed that radiation produced marked damage that was not reversed by treatments. However, gonadal restructuring and recovery of spermatogenesis in treated animals may to reflect attenuation of radiation-induced damages and potential start of recovery.

Evaluating the effect of silver nanoparticles on testes of adult albino rats (histological, immunohistochemical and biochemical study).

Silver nanoparticles (AgNPs) are widely used in medicine, however, they have toxic impacts on different organs. AgNPs distribution to the testes was reported, so, we aimed to study the effect of intraperitoneal injection of AgNPs, at different concentrations and different time durations, on adult rat testes. Sixty healthy adult male Wistar albino rats were divided into three groups; control group (Group I) and two experimental groups (Groups II & III), each of which were subdivided into two subgroups. Rats in group II were exposed for 7 days to low and high doses of AgNPs, respectively. Rats in group III were exposed for 28 days to low and high doses of AgNPs, respectively. Testicular sections were stained with H&E, Toluidine blue, Immunohistochemical staining for Ki-67 and CD68 and Electron microscope examination were performed. Serum testosterone level and Quantitative Real-Time PCR for spermatogenesis genes were measured. Group IIa & IIb showed thickened capsule studded with nanoparticles, congested blood vessels, disorganized seminiferous tubules (Sts) and detached germinal epithelium. Group IIIa & IIIb showed marked reduction in the germinal epithelium, and shrunken Sts with the absence of sperms in most of them, which was more evident with higher doses of AgNPs. Significant decrease in cell proliferation and increase in interstitial tissue macrophages were more detected in groups II & III than in the control group. Decreased serum testosterone and decreased expression levels of spermatogenesis genes in groups IIa, IIb & IIIa, IIIb than in the control group were observed. IN CONCLUSION: intraperitoneal injection of AgNPs adversely affected the structure of adult rat testes. The tissue damage was more manifested with increased dose and duration of exposure.

Methotrexate-induced germ cell toxicity and the important role of zinc and SOD1: Investigation of molecular mechanisms.

Zinc (Zn) was proved to be a germ cell protectant against various disease conditions and toxic insults. Besides other mechanisms, here we have explored the important role of Zn and Zn-dependent SOD1in methotrexate (MTX)-induced germ cell damage. MTX was given 5 mg/kg i.p. once a week for four consecutive weeks, while Zn was supplemented daily at the doses of 3 and 6 mg/kg i.p. for four consecutive weeks. After four weeks of treatment the animals were sacrificed and observed for various end points. There were several histopahtological alterations in the testes like desquamation and altered tubular structures. DNA damage was also increased by MTX as evident by TUNEL assay. Sperm head abnormalities were increased in case of MTX treated animals. Protein expressions of PCNA, BCl-2/Bax, SOD, catalase and GPX5 were found to be altered by the MTX treatment. To further investigate the role of Zn and Zn-dependent SOD1, rats were injected intratesticularly with diethyldithiocarbamate (DEDTC) for three days after MTX 20 mg/kg i.p. was given on the first day. DEDTC in combination with MTX was found to significantly decrease the protein expressions of SOD1, catalase, Nrf2 and GPX4, along with deranged histology. This study adds to the point that Zn might be a better germ cell protectant and deserve further investigation.

Protective effects of Artocarpus altilis (Moraceae) on cadmium-induced changes in sperm characteristics and testicular oxidative damage in rats.

Cadmium (Cd) is a major environmental toxicant and an endocrine disruptor. We investigated the protective effects of methanol extract of Artocarpus altilis (AA) against Cd-induced testicular damage in rats while quercetin (Que) served as standard. The total flavonoids and phenolic contents (TFC and TPC), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl (OH) radicals scavenging activities of AA were determined. In vivo, thirty male Wistar rats were assigned to six groups and orally treated with corn oil (control), Cd alone, Cd+Que, Cd+AA, Que and AA alone. Que and AA were given at doses of 25 and 200 mg kg(-1), respectively, for 3 weeks and challenged with two doses of Cd (1.5 mg kg(-1)). Results showed that TFC and TPC of AA increased with increase in concentration. AA scavenged DPPH and OH radicals in a dose-dependent manner. Administration of Cd significantly increased the relative weight of testis of rats. Lipid peroxidation was significantly increased while antioxidant parameters decreased in testis of Cd-treated rats. Also, Cd-treated rats had significantly reduced sperm count, motility, sialic acid, luteinising hormone and testosterone relative to controls. Pre-treatment with AA or Que significantly attenuated the biochemical alterations observed in Cd-treated rats. Overall, AA protects against Cd-induced testicular damage via antioxidative mechanism.

Zinc protects cyclophosphamide-induced testicular damage in rat: involvement of metallothionein, tesmin and Nrf2.

The role of zinc (Zn) in the protection of germ cells against testicular toxicants has long been elucidated, but the exact molecular mechanisms have not yet been explored. Cyclophosphamide (CP), one of the most commonly used anticancer drugs survived ages of treatment, but the unwanted toxicity limits its clinical usage. The present investigation was aimed to explore the role of Zn and its associated pathways in CP-induced testicular toxicity in S.D. rat. CP was administered in saline 30 mg/kg 5× weekly for 3 weeks (total dose of 450 mg/kg) by i.p. route, while Zn was supplemented by oral route at the doses of 1, 3, 10mg/kg/day for 3 weeks. CP significantly reduced Zn levels in serum and testes, body and testicular weight, sperm count and motility, spermiogenic cells, plasma testosterone and significantly increased the oxidative stress, sperm head abnormalities, sperm DNA damage with decreased chromatin and acrosome integrity; while Zn supplementation ameliorated the same. The present results demonstrated that Zn supplementation protected against CP-induced testicular damages by modulating metallothionein (MT), tesmin and Nrf2 associated pathways. Thus Zn supplementation during anticancer therapy might be potentially beneficial in reducing the off target effects associated with oxidative stress.

Short-term levosimendan treatment protects rat testes against oxidative stress

The objective of this study was to evaluate the effect of short-term levosimendan exposure on oxidant/antioxidant status and trace element levels in the testes of rats under physiological conditions. Twenty male Wistar albino rats were randomly divided into two groups of 10 animals each. Group 1 was not exposed to levosimendan and served as control. Levosimendan (12 µg/kg) diluted in 10 mL 0.9% NaCl was administered intraperitoneally to group 2. Animals of both groups were sacrificed after 3 days and their testes were harvested for the determination of changes in tissue oxidant/antioxidant status and trace element levels. Tissue malondialdehyde (MDA) was significantly lower in the levosimendan group (P < 0.001) than in the untreated control group and superoxide dismutase and glutathione peroxidase (GSH-Px) levels were significantly higher in the levosimendan group (P < 0.001). Carbonic anhydrase, catalase and GSH levels were not significantly different from controls. Mg and Zn levels of testes were significantly higher (P < 0.001) and Co, Pb, Cd, Mn, and Cu were significantly lower (P < 0.001) in group 2 compared to group 1. Fe levels were similar for the two groups (P = 0.94). These results suggest that 3-day exposure to levosimendan induced a significant decrease in tissue MDA level, which is a lipid peroxidation product and an indicator of oxidative stress, and a significant increase in the activity of an important number of the enzymes that protect against oxidative stress in rat testes.

Altered testicular morphology and oxidative stress induced by cadmium in experimental rats and protective effect of simultaneous green tea extract / Morfología testicular alterada y stress oxidativo inducido por cadmio en ratas de experimentación y el efecto protector del extracto simultáneo del té verde

Cadmium (Cd), is an environmental and industrial pollutant that affects the male reproductive system. Cd induces its effect by affecting tissue antioxidant enzyme systems. Green tea extract (GTE) is an antioxidant and free radicals scavenger and has a chelating property. The purpose of this study was to investigate the protective effect of GTE against testes damage induced by Cd. Four groups of male rats, were utilized as following: Controls, GTE treated, Cd treated and Cd + GTE, treated rats at the same doses. The rats received GTE and or Cd orally in drinking water. After 5 weeks, the animals were sacrificed and testes were removed for microscopic and Biochemical evaluation. The levels of lipid peroxides (LPO) and glutathione (GSH) were detected in the tissue homogenates of rat testes. The current study showed marked morphological changes in the form of swelling, congestion, hemorrhage and necrosis in testes of rats treated with Cd alone. However, the rats treated with Cd+GTE showed milder edema, congestion and minute foci of necrosis in the testes. The LPO levels were significantly higher as compared to control and of GSH were significantly lower in Cd-treated rats but when GTE was co-administrated with Cd, there was an effective reduction in oxidative stress as shown by a significant rise of GSH level. In conclusion, the rats received GTE + Cd could enhance antioxidant/ detoxification system which consequently reduced the oxidative stress in rat testes. The beneficial effect of GTE is thus potentially reducing Cd toxicity and tissue damage.

El cadmio (Cd), es un contaminante del medio ambiente e industrial que afecta al sistema reproductivo masculino. Cd induce su efecto por afección de los sistemas enzimáticos antioxidantes de los tejidos. El extracto de té verde (ETV) es un antioxidante y buscador de radicales libres y tiene una propiedad quelante. El objetivo de este estudio fue investigar el efecto protector de ETV contra daños provocado por Cd a los testículos. Cuatro grupos de ratas macho, se utilizaron: Controles, tratados con ETV, tratados con Cd y tratados con Cd + ETV, todas las ratas tratadas con las mismas dosis. Las ratas recibieron ETV o Cd por vía oral en el agua potable. Después de 5 semanas, los animales fueron sacrificados y los testículos fueron retirados para la evaluación microscópica y bioquímica. Los niveles de peróxidos lípidos (LPO) y de glutation (GSH) fueron detectados en el tejido homogenizado de rata testículos. El estudio demostró marcados cambios morfológicos como inflamación, congestión, hemorragia y necrosis en los testículos de las ratas tratadas solamente con Cd. Sin embargo, las ratas tratadas con Cd + ETV mostraron leves signos de edema, congestión y focos de necrosis en los testículos. Los niveles de LPO fueron significativamente mayores en comparación con el control y la de GSH fue significativamente menor en las ratas tratadas con Cd, pero cuando ETV fue co-administrado con Cd, hubo una reducción efectiva en el estrés oxidativo, como lo demuestra el aumento significativo del nivel de GSH. En conclusión, las ratas recibieron GTE + Cd que podría aumentar el sistema antioxidante / desintoxicación, por tanto, reducir el estrés oxidativo en los testículos de ratas. El efecto beneficioso de GTE es reducir la toxicidad y el daño tisular causado Cd.