Regulation of Eclipta prostrata L. components on cigarette smoking‐induced autophagy of bronchial epithelial cells via keap1‐Nrf2 pathway

Cigarette smoking extract (CSE)‐induced autophagic injury has been regarded as an important contributor to the pathogenesis of lung cancer. We previously found that Eclipta prostrata L. component (CCE) reduced CSE‐induced bronchial epithelial cells damage. However, the mechanism remains unknown. Human normal bronchial epithelial cells (NHBE) were exposed to CSE to establish stress model. Nrf2‐siRNA and Keap1‐siRNA transfection were performed. mRFP‐GFP‐LC3 dual fluorescence and transmission electron microscopy were used to observe the autophagic characteristics. CCE prevented CSE‐induced Nrf2 transfer into cytoplasm and up‐regulated Keap1 level of NHBE cells. Furthermore, CCE significantly increased p‐p16, p‐p21 and p‐p53 phosphorylation levels in Nrf2‐siRNA‐ or Keap1‐siRNA‐transfected cells. As demonstrated by transmission electron microscopy and mRFP‐GFP‐LC3 dual fluorescence assays, CCE mitigated autophagic injury, and also down‐regulated autophagy‐related Beclin‐1, LC3II/LC3I ratio, Atg5 and ATF4 levels. Our findings showed the attenuation of CCE on CSE‐induced NHBE cells injury was associated with Nrf‐2‐mediated oxidative signaling pathway.     

Naringenin attenuates CCl4‐induced hepatic inflammation by the activation of an Nrf2‐mediated pathway in rats

The possible protective effects of naringenin, a naturally occurring citrus flavonone, on carbon tetrachloride (CCl₄)‐induced liver injury in rats and the mechanism underlying its effects were investigated. Forty rats were divided into five groups. Rats in Groups I and II served as the normal and injured liver groups, respectively; Group III rats were treated with the standard drug silymarin as a positive control; and rats in Groups IV and V (naringenin‐treated groups) were administrated 50 mg/kg, p.o., naringenin for 7 days. Liver samples were collected to evaluate mRNA and protein expression, histological changes and oxidative stress. Naringenin inhibited lipid peroxidation and reduced serum levels of hepatic enzymes induced by CCl₄. In addition, naringenin increased the liver content of reduced glutathione and the activity of anti‐oxidant enzymes in rats treated with CCl₄. Naringenin attenuated liver inflammation by downregulating CCl₄‐induced activation of tumour necrosis factor (TNF)‐α, inducible nitric oxide synthase (iNOS) and cyclo‐oxygenase (COX‐2) at both the protein and mRNA levels. Naringenin treatment significantly increased NF‐E2‐related factor 2 (Nrf2) and heme oxygenase (HO‐1) expression in injured livers. In rats treated with CCl₄ alone, decreases were seen in nuclear Nrf2 expression and in the mRNA levels of its target genes (e.g. HO‐1, NQO1 and glutathione S‐transferase alpha 3 (GST‐a3)). Together, the results suggest that naringenin can protect the liver against oxidative stress, presumably by activating the nuclear translocation of Nrf2 as well as attenuating the TNF‐α pathway to elicit an anti‐inflammatory response in liver tissue.     

Hepatoprotective effect of ginsenoside Rg1 from Panax ginseng on carbon tetrachloride‐induced acute liver injury by activating Nrf2 signaling pathway in mice

Oxidative stress and inflammatory response are well known to be involved in the pathogenesis of acute liver injury. This study was performed to examine the hepatoprotective effect of ginsenoside Rg1 (Rg1) against CCl₄‐induced acute liver injury, and further to elucidate the involvement of Nrf2 signaling pathway in vivo and in vitro. Mice were orally administered Rg1 (15, 30, and 60 mg/kg) or sulforaphane (SFN) once daily for 1 week prior to 750 μL/kg CCl₄ injection. The results showed that Rg1 markedly altered relative liver weights, promoted liver repair, increased the serum level of TP and decreased the serum levels of ALT, AST and ALP. Hepatic oxidative stress was inhibited by Rg1, as evidenced by the decrease in MDA, and increases in GSH, SOD, and CAT in the liver. Further research demonstrated that Rg1 suppressed liver inflammation response through repressing the expression levels of inflammation‐related genes including TNF‐α, IL‐1β, IL‐6, COX‐2, and iNOS. In addition, Rg1 enhanced antioxidative stress and liver detoxification abilities by up‐regulating Nrf2 and its target‐genes such as GCLC, GCLM, HO‐1, NQO1, Besp, Mrp2, Mrp3, Mrp4, and down‐regulating Cyp2e1. However, the changes in Nrf2 target‐genes, as well as ameliorative liver histology induced by Rg1 were abrogated by Nrf2 antagonist all‐transretinoic acid in vivo and Nrf2 siRNA in vitro. Overall, the findings indicated that Rg1 might be an effective approach for the prevention against acute liver injury by activating Nrf2 signaling pathway.     

Epigallocatechin‐3‐gallate partially restored redox homeostasis in arsenite‐stressed keratinocytes

Arsenite (AsIII) is known for inducing severe oxidative stress and skin carcinogenesis. Contrastingly, phytochemical, epigallocatechin‐3‐gallate (EGCG) combats toxic insults. Our study focused on the effect of EGCG on redox status of AsIII‐stressed normal human keratinocytes, HaCaT cells. EGCG (50 μm ) increased the cell viability by 29% in AsIII (50 μm ) insulted HaCaT cells but exhibited pro‐oxidant activity by elevated expression of the oxidative stress markers. EGCG was effective not only in reducing AsIII‐induced nuclear expression of Nrf2 and Nrf2Ser40 but also in increasing nuclear expression of Keap1 both at protein and mRNA level. EGCG did not have similar effects on all Nrf2 downstream targets. EGCG elevated expression of HO‐1 and γ‐GCL,showed no change in MRP1 but decreased superoxide dismutase, NAD(P)H dehydrogenase quinone 1 and glutathione S transferase activity in AsIII‐treated HaCaT cells. EGCG along with AsIII caused decreased phosphorylation of Nrf2 at ser40 residue, which might have facilitated Keap1‐mediated nuclear export and degradation of Nrf2 and paved the pro‐survival signal for AsIII‐insulted HaCaT cells. In conclusion, it might be indicated that EGCG in spite of inducing the pro‐oxidant effect was effective in increasing the viability of AsIII‐treated HaCaT cells by partially restoring the Nrf2/Keap1‐mediated signaling axis.     

Molecular mechanism of oxidative damage of lung in mice following exposure to lanthanum chloride

Exposure to lanthanoids (Ln) elicits an adverse response such as oxidative injury of lung in animals and human. The molecular targets of Ln remain unclear. In the present study, the function and signal pathway of nuclear factor erythroid 2 related factor 2 (Nrf2) in LaCl₃‐induced oxidative stress in mouse lung were investigated. Mice were exposed to 2, 5, and 10 mg/kg body weight by nasal administration for 6 consecutive months. With increased doses, La was markedly accumulated and promoted the reactive oxygen species (ROS) production in the lung, which in turn resulted in peroxidation of lipids, proteins and DNA, and severe pulmonary damages. Furthermore, LaCl₃ exposure could significantly increase levels of Nrf2, heme oxygenase 1 (HO‐1) and glutamate‐cysteine ligase catalytic subunit (GCLC) expressions in the LaCl₃‐exposed lung. These findings imply that the induction of Nrf2 expression is an adaptive intracellular response to LaCl₃‐induced oxidative stress in mouse lung, and that Nrf2 may regulate the LaCl₃‐induced pulmonary damages. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 357–365, 2015.     

PM2.5‐induced lung inflammation in mice: Differences of inflammatory response in macrophages and type II alveolar cells

Particulate matter 2.5 (<PM2.5 μm) leads to chronic obstructive pulmonary disease. In this study, biomarkers related to inflammation and oxidative stress in vitro and in vivo experiments were investigated to clarify the PM2.5‐induced lung inflammation mechanisms. In an in vitro study using RAW264.7 cells, PM2.5 caused phosphorylation of nuclear factor‐κB, p38 mitogen‐activated protein kinase and extracellular response kinases, an increase of proinflammatory gene and protein expressions (e.g. monocyte chemotactic protein‐1, tumor necrosis factor‐α). These biomarkers were substantially attenuated by polymyxin B (PMB). PM2.5 induced heme oxygenase‐1 (HO‐1) gene, which was attenuated by N‐ acetylcysteine (NAC). However, the suppressive effects of NAC on inflammatory biomarkers were very weak. In bone marrow‐derived macrophages (BMDMs) of wild‐type BALB/c mice, the effects of PMB and NAC on PM2.5‐induced inflammatory responses were similar to RAW264.7 cells. In BMDMs of MyD88^−/− mice, PM2.5‐induced proinflammatory mediators were substantially more attenuated. PM2.5 caused an increase of proinflammatory gene expressions (interleukin‐6, cyclooxygenase 2) and HO‐1 gene in MLE‐12 cells (mouse alveolar cell line). These biomarkers were substantially attenuated by NAC, but not by PMB. When BALB/c mice were exposed intratracheally to 0.2 mg PM2.5, PM2.5 caused severe lung inflammation, an increase of neutrophils along with proinflammatory mediators in bronchoalveolar lavage fluid. The inflammation was attenuated by NAC, particularly by NAC + PMB, but not by PMB alone. These results indicate that macrophages may act sensitively to lipopolysaccharide (LPS) present in PM2.5 and release proinflammatory mediators via the LPS/MyD88 pathway. However, type II alveolar cells may react sensitively to oxidative stress induced by PM2.5 and cause inflammatory response. Therefore, overall, PM2.5 may cause predominantly oxidative stress‐dependent inflammation rather than LPS/MyD88‐dependent inflammation in type II alveolar cell‐rich lungs. Copyright © 2017 John Wiley & Sons, Ltd.     

Curcumin ameliorates asthmatic airway inflammation by activating nuclear factor‐E2‐related factor 2/haem oxygenase (HO)‐1 signalling pathway

Previous studies have shown that curcumin alleviates asthma in vivo. However, the relationship between curcumin and the nuclear factor‐E2‐related factor 2 (Nrf2)/haem oxygenase (HO)‐1 pathway in asthma treatment remains unknown. The aim of the present study was to investigate the mechanisms of curcumin involved in the amelioration of airway inflammation in a mouse asthma model. Curcumin was administrated to asthmatic mice, and bronchoalveolar lavage fluid was collected. Inflammatory cell infiltration was measured by Giemsa staining. Immunoglobulin E production in bronchoalveolar lavage fluid was measured by enzyme–linked immunosorbent assay. Histological analyses were evaluated with haematoxylin‐eosin and periodic acid‐Schiff staining. Airway hyperresponsiveness was examined by whole‐body plethysmography. Nuclear factor‐E2‐related factor 2, HO‐1, nuclear factor‐κB and inhibitory κB/p‐inhibitory κB levels in lung tissues were detected by western blot, and Nrf2 activity was measured by electrophoretic mobility shift assay. Tumour necrosis factor‐α, interleukin (IL)‐1β, and IL‐6 levels in the small interfering RNA‐transfected cells were detected by enzyme–linked immunosorbent assay. Curcumin treatment significantly reduced immunoglobulin E production, attenuated inflammatory cell accumulation and goblet cell hyperplasia, and ameliorated mucus secretion and airway hyperresponsiveness. Nuclear factor‐E2‐related factor 2 and HO‐1 levels in lung tissues were significantly increased. Meanwhile, Nrf2 activity was enhanced. Nuclear factor‐κB and p‐inhibitory κB levels were elevated in the lung tissue of ovalbumin‐challenged mice. Both were restored to normal levels after curcumin treatment. Haem oxygenase‐1 and nuclear Nrf2 levels were enhanced in dose‐ and time‐dependent manners in curcumin‐treated RAW264.7 cells. Curcumin blocked lipopolysaccharide‐upregulated expression of tumour necrosis factor‐α, IL‐1β, and IL‐6. After the cells were transfected with HO‐1 or Nrf2 small interfering RNA, lipopolysaccharide‐induced pro‐inflammation cytokine expression was significantly restored. In summary, curcumin might alleviate airway inflammation in asthma through the Nrf2/HO‐1 pathway, potentially making it an effective drug in asthma treatment.     

N‐acetylcysteine alleviated paraquat‐induced mitochondrial fragmentation and autophagy in primary murine neural progenitor cells

The developing brain is uniquely vulnerable to toxic chemical exposures. Studies indicate that neural stem cell (NSC) self‐renewal is susceptible to oxidative stress caused by xenobiotics. However, the impact of antioxidants on NSC self‐renewal and the potential mechanisms remain elusive. In this study, primary murine neural progenitor cells (mNPCs) from the subventricular zone were used as a research model. In addition, paraquat (PQ) was used to elicit oxidative stress and N‐acetylcysteine (NAC) was used as a powerful antioxidant. mNPCs were treated with 80 μm PQ for 24 hours with or without 4 hours of NAC pretreatment. Our results showed that PQ treatment increased intracellular reactive oxygen species production, decreased cell viability and DNA synthesis, and promoted cell apoptosis. Meanwhile, pretreatment with NAC alleviated PQ‐induced cytotoxicity in mNPCs. To elucidate the mechanisms further, we found that NAC pretreatment prevented PQ‐induced reactive oxygen species production, mitochondrial fragmentation and autophagy in mNPCs. NAC‐pretreated cells showed increased anti‐apoptotic protein Bcl‐2 and decreased pro‐apoptotic protein Bax expression. Similarly, NAC pretreatment increased p‐mTOR and decreased LC3B‐II protein expression. Moreover, NAC decreased mitophagy related mRNA Pink1 and Parkin expression. Taken together, our results suggested that the antioxidant NAC treatment significantly attenuated PQ‐induced mNPC self‐renewal disruption through decreasing autophagy and salvaging mitochondrial morphology. These findings revealed a potential mechanism for neurological treatment relating to antioxidant and suggested potentially relevant implications for PQ‐related neurodegenerative disorders. Thus, our study also provided insight into therapeutic strategies for the neurotoxic effects of oxidative stress‐associated toxicants.     

Epigallocatechin‐3‐Gallate Attenuates Oxidative Stress and Inflammation in Obstructive Nephropathy via NF‐κB and Nrf2/HO‐1 Signalling Pathway Regulation

Oxidative stress and inflammation contribute importantly to the pathogenesis of chronic kidney disease (CKD). Epigallocatechin‐3‐gallate (EGCG), which is the most abundant and most active catechin polyphenol extracted from green tea, has been proved to have many bioactivities. In this study, the renoprotective effect of EGCG was evaluated in a widely used kidney disease model, the unilateral ureteral obstruction (UUO) mice model. After 14 days of EGCG administration, mean arterial blood pressure, body‐weight and obstructed kidney weight were measured. Levels of blood urea nitrogen (BUN) and creatinine (CR) and activities of glutamic–pyruvic transaminase (GPT) and lactate dehydrogenase (LDH) in serum were estimated as indicators of renal function. Periodic acid–Schiff (PAS) staining was performed to observe the pathological changes of the obstructed kidney. Antioxidant enzymes and pro‐inflammatory cytokine production were estimated to reflect the oxidative stress and inflammatory state in the obstructed kidney. Finally, the main proteins in the NF‐κB and Nrf2 signalling pathway and DNA binding activity of NF‐κB and Nrf2 were measured to investigate the effect of EGCG on these two pathways. The results demonstrated that EGCG could restore UUO‐induced kidney weight loss and renal dysfunction. In addition, UUO‐induced oxidative stress and inflammatory responses in the obstructed kidney were also prevented by EGCG. Furthermore, EGCG could induce both NF‐κB and Nrf2 nuclear translocation in the UUO kidney and promote heme oxygenase‐1 (HO‐1) production. These results indicated that the renoprotective effect of EGCG might be through its NF‐κB and Nrf2 signalling pathway regulations.     

Curcumin alleviates glucocorticoid‐induced osteoporosis by protecting osteoblasts from apoptosis in vivo and in vitro

Curcumin, an active component of the rhizomes of Curcumin longa L., possesses broad anti‐inflammation and anti‐cancer properties. Curcumin was previously reported to be capable of protecting ovariectomized rats against osteoporosis. However, the effect of curcumin on glucocorticoid‐induced osteoporosis (GIO) is not yet clear. The present study investigated the effects of curcumin on dexamethasone (Dex)‐induced osteoporosis in vivo and Dex‐induced osteoblast apoptosis in vivo and in vitro. The GIO rat model was induced by subcutaneous injection of Dex for 60 days and verified to be successful as evidenced by the significantly decreased bone mineral density (BMD) determined using dual X‐ray absorptiometry. Subsequently, curcumin administration (100 mg/kg) for 60 days obviously increased BMD and bone‐alkaline phosphatase, decreased carboxy‐terminal collagen cross links, enhanced bone mechanical strength, and improved trabecular microstructure, thereby alleviating Dex‐induced osteoporosis. Mechanically, curcumin remarkably reversed Dex‐induced femoral osteoblast apoptosis in vivo. In cultured primary osteoblasts, pretreatment with curcumin concentration‐dependently decreased the number of Dex‐induced apoptotic osteoblasts by down‐regulating the ratio of Bax/Bcl‐2 as well as the levels of cleaved caspase‐3 and cleaved poly ADP‐ribose polymerase (PARP). Moreover, curcumin pretreatment activated extracellular signal regulated kinase (ERK) signalling in Dex‐induced osteoblasts by up‐regulating the expression level of p‐ERK1/2. Taken together, our study demonstrated that curcumin could ameliorate GIO by protecting osteoblasts from apoptosis, which was possibly related to the activation of the ERK pathway. The results suggest that curcumin may be a promising drug for prevention and treatment of GIO.     

Di (2‐ethylhexyl) phthalate induces cytotoxicity in HEK‐293 cell line,implication of the Nrf‐2/HO‐1 antioxidant pathway

The di (2‐ethylhexyl) phthalate (DEHP) is a plasticizer used in the polyvinyl chloride industry. Human exposure to this plasticizer is inevitable and contributes to several side effects. In this study, we examined whether DEHP induces apoptosis and oxidative stress in embryonic kidney cells (HEK‐293) and whether the nuclear factor E2‐related factor 2 (Nrf‐2)/heme oxygenase‐1 (HO‐1) antioxidant pathway is involved in the pathogenesis of this process. We demonstrated that DEHP is cytotoxic to HEK‐293 cells. It causes oxidative damage through the generation of free radicals, induces lipid peroxidation, and alters superoxide dismutase and catalase activities. Simultaneously, DEHP treatment decreases the expression and the protein level of Nrf‐2 and HO‐1. Inhibition of the Nrf‐2/HO‐1 pathway is related to the mitochondrial pathway of apoptosis. This apoptotic process is characterized by a loss of mitochondrial transmembrane potential (ΔΨm) and upregulation of the expression of caspase‐3 mRNA as well as its protein level.     

Decrease in Oxidative Stress Parameters after Post‐Ischaemic Recombinant Human Erythropoietin Administration in the Hippocampus of Rats Exposed to Focal Cerebral Ischaemia

Recombinant human erythropoietin (rhEpo) is a multi‐functional drug with antioxidant potential. However, the underlying molecular mechanisms of its action are still unclear. The purpose of this study was to investigate the effects of rhEpo on the brain infarct volume as well as on the levels of the neuronal damage, oxidative stress parameters and active caspase‐3, nuclear factor erythroid 2‐related factor 2 (Nrf2) and haemeoxygenase‐1 (HO‐1) expressions in the hippocampi of rats exposed to the right middle cerebral artery occlusion (MCAO) for 1 hr. Ischaemic animals received either vehicle or rhEpo (5000 IU/kg, i.p.) immediately or 3 hr after the induction of ischaemia. Sham‐operated, vehicle‐treated animals served as the control group. Rats were killed 24 hr after the onset of the ischaemic or sham experimental procedure. MCAO caused ipsilateral brain infarction within the striatum and cortex. In the CA1 region of the hippocampi, we did not find significant neuronal loss, but a statistically significant rise in the active caspase‐3 and Nrf2 protein expressions was registered. We detected also significant increases in the hippocampal levels of oxidative stress parameters (thiobarbituric acid‐reactive substances, superoxide dismutase, glutathione peroxidase). Post‐ischaemic administration of rhEpo significantly reduced the brain infarct volume, decreased levels of all tested oxidative stress parameters and increased the Nrf2 expression level. These findings suggest that decrease in oxidative stress parameters in the hippocampus could be an early indicator of post‐ischaemic neuroprotective effect of rhEpo in rats exposed to focal cerebral ischaemia and that this effect could be attributable to additional post‐ischaemic activation of Nrf2 endogenous antioxidant system.     

AQP4‐knockout aggravation of isoprenaline‐induced myocardial injury is mediated by p66Shc and endoplasmic reticulum stress

Aquaporin 4 (AQP4) is a type of water channel protein that maintains the water balance of cardiomyocytes. However, the physiological role of AQP4 in cardiovascular disease is poorly understood. We wanted to explore whether p66Shc and endoplasmic reticulum stress participates in AQP4 knockout (KO)‐mediated cardiac injury. There were two types of mice: AQP4 knockout and wild‐type mice. Each type was randomly divided into three groups: Control group, isoprenaline stimulation group (ISO, 1 mg/kg, s.c., 5 days), and apocynin treatment group (APO, 100 mg/kg, p.o., 3 days). H9c2 rat cardiomyocytes were cultured for RNA interference of AQP4. Results showed increased left ventricular weight index and more severe myocardial inflammation were induced in AQP4 knockout mice relative to wild‐type mice, accompanied by significantly increased levels of the oxidative stress biomarkers MDA and NOX4. In addition, the expressions of p66Shc, ER stress markers PERK, GRP78 and CHOP and proinflammatory factors such as ET_A, IL6 and TNFα were upregulated in the myocardium of AQP4 knockout mice or AQP4 siRNA treated cardiomyocytes, whereas CASQ2 was downregulated. ISO stimulation aggravated these abnormalities, which were significantly attenuated by apocynin. This study showed that AQP4 knockout mice were susceptible to cardiac injury induced by ISO. The mechanism was closely connected with p66Shc and proinflammatory factors. Endoplasmic reticulum stress was also involved in the pathological process.     

β‐LAPachone ameliorates doxorubicin‐induced cardiotoxicity via regulating autophagy and Nrf2 signalling pathways in mice

β‐LAPachone (B‐LAP) is a naphthoquinone that possesses antioxidant properties. In the present investigation, the protective effect of B‐LAP against doxorubicin (DOX)‐induced cardiotoxicity was examined in mice. Thirty‐five mice were divided into 5 groups: control group, B‐LAP (5 mg/kg) group, DOX (15 mg/kg) group, DOX+B‐LAP (2.5 mg/kg) group and DOX+B‐LAP (5 mg/kg) group. B‐LAP was administered orally for 14 days of experimental period. A single dose of DOX (15 mg/kg) was injected intraperitoneally on day 3. Cardiac function, histoarchitecture, indices of oxidative stress and circulating markers of cardiac injury were examined. B‐LAP (5 mg/kg) decreased serum levels of lactate dehydrogenase (LDH), creatine kinase MB (CK‐MB) and cardiac troponin I (cTnI), and ameliorated cardiac histopathological alterations. In addition to increasing cellular NAD⁺/NADH ratio, B‐LAP up‐regulated the cardiac levels of SIRT1, beclin‐1, p‐LKB1 and p‐AMPK, and reduced the cardiac levels of p‐mTOR, interleukin (IL)‐1β, TNF (tumour necrosis factor)‐α and caspase‐3. B‐LAP also elevated the nuclear accumulation of Nrf2 and simultaneously up‐regulated the protein levels of haem oxygenase (HO‐1) and glutathione S‐transferase (GST) in the hearts of DOX mice. While B‐LAP reduced malondialdehyde concentrations in heart of DOX‐treated mice, it further promoted the activities of cardiac superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT).In accordance with increased cell survival, B‐LAP significantly improved the cardiac function of DOX mice. Collectively, these findings underline the protective potential of B‐LAP against DOX‐induced cardiotoxicity by regulating autophagy and AMPK/Nrf2 signalling pathway in mice.     

Di‐(2‐ethylhexyl) phthalate (DEHP)‐induced testicular toxicity through Nrf2‐mediated Notch1 signaling pathway in Sprague–Dawley rats

Di‐(2‐ethylhexyl) phthalate (DEHP) is an environmental endocrine disruptor widely used in China that is harmful to the male reproductive system. Many studies have shown that DEHP causes testicular toxicity through oxidative stress, but the specific mechanism is unknown. Because the Notch pathway is a key mechanism for regulating cell growth and proliferation, we investigated whether Notch is involved in DEHP‐induced testicular toxicity and whether vitamins E and C could rescue testicular impairment in Sprague–Dawley (SD) rats. Compared with the control group, we found that DEHP exposure induced testicular toxicity through oxidative stress injury, and it decreased the testosterone level (P < .01) and upregulated nuclear factor‐erythroid 2 related factor (Nrf2) expression (P < .01). Therefore, because oxidative stress might be the initiating factor of DEHP‐induced testicular toxicity, treatment with the antioxidant vitamins E and C activated the Notch1 signaling pathway in the testis and in Leydig cells. Treatment with vitamins E and C normalized the oxidative stress state after DEHP exposure and restored testicular development to be similar to the control group. In summary, antioxidant vitamins E and C may be used to treat DEHP‐induced testicular toxicity.