| Background: Di-n-butylphthalate(DBP),has been well defined as anti-androgenic effects by interfering with production and functional activity of testosterone.Results from recent epidemiological studies indicate the association of phthalate esters exposure with a number of human reproductive disorders including hypospadias,cryptorchidism,and spermatogenesis dysfunction.Oxidative stress and mitochondrial dysfunction in testicular cells were suggested to contribute to phthalate-induced reproductive disorders.Testicular cell is one of the most important targets of testicular toxicity caused by phthalate esters.Meanwhile,redox-sensitive NF-E2 related factor-2(Nrf2)is a key transcriptional factor for regulation of oxidative stress in vivo.Fortunately,we have found that Nrf2 and the downstream genes were significantly up-regulated in fetal testicular cells after utero exposure,which indicates the involvement of Nrf2 in protection against oxidative damage.The purpose of our research was to investigate the molecular toxicological mechanism of DBP by analyzing the changes of Nrf2 nuclear translocation and the downstream anti-oxidative proteins,comparing the different outcomes when the expression of Nrf2 has been regulated by the adenovirus transfection,small RNA interfering and sulforaphane.Furthermore,the protective role of Nrf2 in oxidative damage in testicular cell will be comfirmed in Nrf2-/-and wild type fetal rats.Our research aims to providing therapeutic evidence for human birth defects caused by endocrine disrupting chemicals.Objective: DBP,widely used as a plasticizerm,is one of the most commonly endocrine-disrupting chemicals in a variety of consumer products,which can disrupt the endocrine systems of humans and wildlife especially in the male reproductive system.Here,this study was aimed to determine whether sulforaphane(SFN)protected against testicular oxidative stress injury induced by DBP in male mice offspring by the role and therapeutic potential of nuclear factor erythroid-related factor 2(Nrf2).Methods: Wild-type(Nrf2+/+)and Nrf2-deficient(Nrf2-/-)mice were randomly divided into four groups:(1)Control group;(2)SFN group;(3)DBP group;and(4)DBP+SFN group.The timed-pregnant mice were given DBP(Solvent: soybean oil)by gastric intubation at a dose of 500 mg/kg body weight(bw)/day from gestation day(GD)14 to GD19 to induce testicular oxidative stress injury in fetal male mice.Subsequently,under anatomic microscope,these mice offspring were sacrificed to collect the testis samples,blood samples in four weeks after birth.Oxidative stress related indexes,including Malondialdehyde(MDA),reactive oxygen species(ROS),total antioxidant capacity(T-AOC)and glutathione(GSH)and antioxidant enzymes,superoxide dismutase(SOD)and catalase(CAT)were detected.Besides,Nrf2,nuclear factor kappa-light-chain-enhancer of activated B cells(NF-? B),hemeoxygenase 1(HO-1)and NAD(P)H-quinone oxidoreductase 1(NQO1)expression levels in the testis were measured by immunohistochemical staining or western blot analysis at the indicated time points.Results: Testicular oxidative stress injury mediated by DBP significantly reduced anogenital distance(AGD),testicular weight,body weight,testicular weight/body weight and AGD/body weight in these 4-week-old male mice offspring,while supplementation of SFN ameliorated these indices in Nrf2+/+ mice,not in Nrf2-/-mice.After DBP stimulation,the testicular morphology,number of testicular cell apoptosis and oxidative stress parameters were exhibited significant changes.However,SFN supplementation showed obvious improvements in Nrf2+/+ mice.In addition,the expression levels of Nrf2,NF-? B,HO-1 and NQO1 in the testis were changed in different treatment groups.Conclusion: In conclusion,these present findings suggested that SFN could effectively protect against DBP-induced testicular oxidative stress injury through Nrf2 signaling pathways in male mice offspring. |
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