tBHQ Group Research Articles

Role of Keap1-Nrf2/ARE signal transduction pathway in protection of dexmedetomidine preconditioning against myocardial ischemia/reperfusion injury.

Objective: To explore the role and mechanism of the Kelch sample related protein-1-nuclear factor erythroid-2 related factor 2/antioxidant response element (Keap1-Nrf2/ARE) signaling pathway in protection of dexmedetomidine (DEX) preconditioning against myocardial ischemia/reperfusion injury (MIRI). Methods: A total of 70 male SD rats were randomly divided into seven equal groups (n=10): blank control (S group), ischemia/reperfusion injury (C group), DEX preconditioning (DEX group), tertiary butylhydroquinone (tBHQ) control (tBHQ group), combined tBHQ and DEX preconditioning (tBHQ+DEX group), all-trans retinoic acid (ATRA) control (ATRA group), and combined ATRA and DEX preconditioning (ATRA+DEX group). Serum creatine kinase-MB (CK-MB) and cardiac troponin I (cTnI) concentrations were measured by ELISA kits, and the infarct size (IS) was assessed by Evan’s blue and 2,3,5-triphenyltetrazolium chloride (TTC) staining. Oxidative stress was assessed through Western blotting for expression of Keap1-Nrf2/ARE pathway members and oxidative stress markers. Results: Cardioprotection of DEX, tBHQ, and tBHQ+DEX preconditioning treatments were shown as lower concentrations of serum CK-MB and cTnI and a smaller IS following MIRI in rats compared with those of MIRI rats without pre-treatment. In addition, tBHQ+DEX preconditioning exhibited stronger myocardial protection compared with DEX preconditioning. Mechanistically, the cardioprotection offered by DEX, tBHQ, and tBHQ+DEX preconditioning treatments was mediated via exerting antioxidant stress through activation of the Keap1-Nrf2/ARE signal transduction pathway. Conversely, the protective effects of DEX were diminished by blocking the Keap1-Nrf2/ARE pathway with inhibitor ATRA. Conclusion: DEX preconditioning protects against MIRI by exerting antioxidant stress through activation of the Keap1-Nrf2/ARE signal transduction pathway, while inhibition of the Keap1-Nrf2/ARE signal transduction pathway reverses the protective effect of DEX preconditioning on MIRI.

The role of the stress-activated transcription factor Nrf2 in OVA-induced food allergy

Abstract Food allergies are rising at a striking rate, but the underlying cause is unclear. The purpose of the studies was to determine the effect of the food preservative tert-butylhydroquinone (tBHQ) in a mouse model of food allergy. Our preliminary studies show that skin-sensitization with OVA induced an elevated OVA-IgE level in mice on a tBHQ diet. Likewise, in response to oral challenge, a greater decrease in body temperature during anaphylaxis was observed in the tBHQ group. Previously published in vitro studies suggest that tBHQ promotes Th2 polarization through activation of the stress-activated transcription factor, Nrf2. Therefore, we proposed the hypothesis that tBHQ exacerbates allergic response in OVA sensitized mice through activation of Nrf2. We implemented adoptive transfers of CD4 T cells from wild-type or Nrf2-null mice into immunodeficient mice (all mice received wild-type B cells). The study revealed marked genotype differences. Notably, dietary tBHQ had little effect on food allergy in recipients of Nrf2-deficient CD4 T cells. These mice showed attenuated sensitization as compared to wild-type CD4 T cells recipients. Strikingly, mice receiving Nrf2-deficient T cells did not become anaphylactic following challenge. In contrast, tBHQ caused an increase in OVA-IgE levels and a greater drop in body temperature in mice receiving wild-type CD4 T cells, suggesting these effects are Nrf2 dependent. In addition, recipients of Nrf2-deficient CD4 T cells showed an attenuated percentage of Th2 cells and mast cell degranulation response, following challenge. Taken together, these data suggest a critical role for Nrf2 during food allergy and demonstrate that tBHQ exacerbates food allergy in a CD4 T cell-Nrf2 dependent manner.

The Food Additive tBHQ Impairs NK Cell Cytotoxicity Against Influenza Infection (FS12-02-19)

ObjectivesWe examined the effects of the food preservative, tert-Butylhydroquinone (tBHQ), on natural killer (NK) cells when infected with influenza in C57Bl/6 mice. Previously, we found tBHQ to negatively impact splenic NK cell effector function in vitro. Therefore, we hypothesized that the consumption of tBHQ would impair the NK cell response against a primary influenza virus infection. MethodsFemale, C57Bl/6 mice were fed either a diet containing 0.0014% tBHQ or a control diet two weeks prior to infection. Mice were instilled intranasally with 21.78 HAU of influenza A/PR/8/34 (H1N1) and were monitored for two days. Body weight was recorded as a measurement for infection. After day two of infection, lungs were collected and processed for analysis by flow cytometry, enzyme-linked immunosorbent assay (ELISA), and total antioxidant capacity (TAC). ResultsThe NK cell activation markers, CD25 and CD69, were not affected by tBHQ consumption. Additionally, tBHQ did not have an effect on maturation of NK cells or interferon (IFN)γ production. Notably, NK cell expression of granzyme B was significantly decreased with tBHQ in infected mice. Furthermore, mice on the tBHQ diet showed decreased TAC after two days of infection compared to mice on the control diet, suggesting increased oxidative stress in the tBHQ group. ConclusionstBHQ had no effect on NK cell activation, maturation, and IFNγ production after two days of influenza infection. However, decreased expression of granzyme B by NK cells suggests tBHQ may impair NK cell cytoxicity during the infection. Moreover, the decrease in TAC suggests increased oxidative stress in the tBHQ-treated mice. Funding SourcesThis study was funded by National Institute of Environmental Health Sciences (ES024966).

Activation of Nrf2/HO-1 pathway protects retinal ganglion cells from a rat chronic ocular hypertension model of glaucoma.

The objective of this work was to find out the effects of nuclear factor erythroid 2-related factor/heme oxygenase-1 (Nrf2/HO-1) pathway on retinal ganglion cell (RGC) injury in glaucoma. The chronic ocular hypertension (COH) rat models of glaucoma were constructed, and intraocular pressure (IOP) and RGC numbers were detected at different time points. Additionally, rats were divided into normal group (normal control rats), model group (COH model rats), and model + tBHQ group (COH model rats treated with Nrf activator, tBHQ). RGC apoptosis was detected by using TUNEL staining, and the expressions of Nrf2/HO-1 were detected by qRT-PCR and western blotting. COH model rats showed significant IOP elevation and the increased mRNA and protein expressions of Nrf2 and HO-1 from 1 to 6weeks after operation, with the evidently decreased RGC numbers at 4weeks and 6weeks after operation (all P < 0.05). Besides, rats in the model group had increased apoptosis index (AI) of RGCs and the elevated mRNA and protein expressions of Nrf2/HO-1 with remarkably reduced RGC numbers when compared with normal control rats, but the model rats treated with tBHQ exhibited an apparent decrease in AI of RGCs, as well as remarkable increases in RGC numbers and the mRNA and protein expression of Nrf2/HO-1 (all P < 0.05). Activation of Nrf2/HO-1 pathway significantly reduced the apoptosis and injury of RGCs in rats with chronic ocular hypertension (COH), thereby protecting RGCs in glaucoma, which could be a promising clinical target to prevent RGC degeneration in glaucoma.

Nrf2-ARE signaling pathway regulates the expressions of A1R and ENT1 in the brain of epileptic rats.

To explore the behavioral changes and the expressions of the A1 receptor (A1R) and balanced nucleoside transporter-1 (ENT1) in the brain of epileptic rats after activating the NF-E2-related factor 2 (Nrf2)-ARE signaling pathway. Adult male Sprague-Dawley (SD) rats were randomly divided into normal control group, epilepsy group, and t-butylhydroquinone (tBHQ) group, with 10 rats in each group. Lithium-pilocarpine induced epilepsy model in rats was established. The first epileptic latency and seizure frequency within 1 hour were observed in each group using the Racine scoring system. HE (Hematoxylin and Eosin) staining was used to observe the pathological lesions in the brain tissue of each group. The expressions of A1R, ENT1, and relative genes in Nrf2-ARE pathway in rat hippocampus was detected by immunohistochemistry and Western blot. Compared with rats in epileptic group, the first seizure latency was prolonged and the seizure frequency decreased in tBHQ group (p<0.05). The degree of brain lesions in tHBQ group was lighter than that of epilepsy group. ENT1 expression in rat hippocampus of epileptic group was significantly upregulated than that of normal control group and tBHQ group. Besides, the protein levels of A1R, Nrf2, HO-1, and ARE in rat hippocampus of epilepsy group markedly decreased compared with those of normal control group. However, protein expressions of A1R, Nrf2, HO-1, and ARE proteins in rat hippocampus of tBHQ group were markedly upregulated. Activation of the Nrf2-ARE signaling pathway can reduce the pathological damage of rat hippocampal neurons, prolong the latency of seizures, and reduce the degree of epileptic seizure in rats.

Effect of tert-Butylhydroquinone on the expression of nuclear factor erythroid 2-related factor 2, heme oxygenase-1 and phosphatidylinositol 3-kinase in high glucose cultured retinal Müller cells

Objective To observe the effect of tert-Butylhydroquinone (tBHQ) on the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase (HO)-1 and phosphatidylinositol 3-kinase (PI3K) in high glucose cultured retinal Muller cells; and to investigate the anti-oxidative stress and anti-apoptotic effects of tBHQ. Methods Retinal Muller cells were divided into normal glucose group (5.5 mmol/L, N group), high glucose group (45 mmol/L, HG group) and tBHQ intervention group (HG+tBHQ group). After retinal Muller cells were cultured with high glucose for 48 hours, the pretreatment with tBHQ (20 μmol/L) induced the expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and HO-1. The Muller cells were identified by immunofluorescence staining. The expressions of Nrf2, HO-1, PI3K, B-cell lymphoma-2 (Bcl-2) and Bax were detected by Western blot and real-time fluorescence quantitative PCR. Flow cytometry was used to detect the apoptosis of retinal Muller cells in rats. Results Muller cytoplasm and nucleus GS showed strong positive, large cell body, abundant cytoplasm, uniform green fluorescence; nuclear DAPI staining round or oval, clear boundary. The expression of Nrf2 protein (t=4.114, P=0.006), HO-1 protein (t=9.275, P=0.000), Nrf2 mRNA (t=7.292, P=0.000) and HO-1 mRNA (t=15.014, P=0.000) in the HG group were higher than those in the N group. The expressions of Nrf2 protein (t=7.847, P=0.000) , HO-1 protein (t=7.947, P=0.000), PI3K protein (t=5.397, P=0.002), Bcl-2 protein (t=6.825, P=0.000), Nrf2 mRNA (t=18.046, P=0.000), HO-1 mRNA (t=39.458, P=0.000), PI3K mRNA (t=4.979, P=0.003) and Bcl-2 mRNA (t=9.535, P=0.000) in the HG+tBHQ group were significantly higher than those in the HG group. The protein and mRNA expressions of Bax protein in the HG+tBHQ group were significantly lower than those in the HG group (t=14.998, 16.520; P=0.000, 0.000). Flow cytometry showed that the apoptosis rate of Muller cells in the HG group was significantly higher than that in the N group (t=39.905, P=0.000). The apoptosis rate of Muller cells in the HG+tBHQ group was significantly lower than that in the HG group (t=21.083, P=0.000). Conclusion tBHQ can inhibit the apoptosis of retinal Muller cells by up-regulating the expression of Nrf2, HO-1 and PI3K. Key words: Hydroquinones; NF-E2-related factor 2; Heme oxygenase (decyclizing); Phosphatidylinositol 3-kinase; Muller cell

Effect of tert-butylhydroquinone on DJ-1/Nrf2 pathway during renal ischemia-reperfusion in diabetic rats

Objective To evaluate the effect of tert-butylhydroquinone (t-BHQ) on DJ-1/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway during renal ischemia-reperfusion (I/R) in diabetic rats. Methods Forty SPF healthy adult male Sprague-Dawley rats, weighing 200-220 g, were divided into 4 groups (n=10 each) using a random number table method: control group (group C), diabetes mellitus group (group D), diabetes mellitus plus renal I/R group (I/R group) and t-BHQ group (group T). Diabetes mellitus was induced by intraperitoneal streptozotocin 60 mg/kg and confirmed by fasting blood glucose level>16.7 mmol/L 72 h later.t-BHQ 50 mg/kg was intraperitoneally injected in 3 times at an interval of 8 h starting from 24 h before surgery in group T, while the equal volume of normal saline was given instead in D and I/R groups.Blood samples were collected from the apex of the heart at 24 h of reperfusion for determination of serum creatinine (Cr), cystatin C (Cys C) and β2-microglobulin (β2-MG) concentrations.The rats were then sacrificed, and kidneys were removed for determination of pathological changes of kidneys (with a light microscope) and for detection of the expression of DJ-1, Nrf2 and heme oxygenase-1 (HO-1) in renal tissues (by Western blot). Results Compared with group C, the concentrations of serum Cr, Cys C and β2-MG and pathological scores were significantly increased, and the expression of DJ-1, Nrf2 and HO-1 was up-regulated in D, I/R and T groups (P<0.05). Compared with group D and group I/R, the concentrations of serum Cr, Cys C and β2-MG and pathological scores were significantly decreased, and the expression of DJ-1, Nrf2 and HO-1 was up-regulated in group T (P<0.05). Conclusion t-BHQ can attenuate renal I/R injury by activating DJ-1/Nrf2 pathway in diabetic rats. Key words: Diabetes mellitus; Kidney; Reperfusion injury; Transcription factors; t-BHQ; DJ-1

Tert-Butylhydroquinone Protects Liver Against Ischemia/Reperfusion Injury in Rats Through Nrf2-Activating Anti-Oxidative Activity

BackgroundHepatic ischemia/reperfusion (I/R) injury is a serious complication that occurs in surgical operations such as hepatectomy and liver transplantation. NF-E2–related factor 2 (Nrf2) is a transcription factor that has been proven against inflammatory and oxidative injury. Tert-butylhydroquinone (tBHQ), a widely used Nrf2 activator, is a common food preservative. In this study, we attempt to investigate the potential protective role of tBHQ in hepatic I/R injury. MethodsTwenty adult male rats were randomly divided into four groups: (1) sham+vehicle group; (2) I/R+vehicle group; (3) sham+tBHQ group; and (4) I/R+tBHQ group. The vehicle or tBHQ was divided into three injections at intervals of 12 hours in a model of hepatic I/R injury. Fluorescence quantitative polymerase chain reaction and Western blot analysis were used to examine Nrf2 mRNA and protein expression. The concentrations of malondialdehyde and superoxide dismutase activity were accessed, respectively. ResultsCompared with the sham+vehicle group, Nrf2 expression, malondialdehyde, content and serum alanine aminotransferase were significantly increased in the I/R+vehicle group, whereas superoxide dismutase activity was significantly decreased. However, in the I/R+tBHQ group, tBHQ ameliorated tissue damage; promoted glutathione-S-transferase, quinine oxidoreductase 1, and glutamate cysteine ligase inductions; and regained redox homeostasis in comparison with the I/R+vehicle group. Furthermore, the present study indicated that preconditioning with tBHQ suppressed the I/R-induced increase in the apoptotic protein levels of caspase-3, as well as the I/R-induced decrease in the levels of anti-apoptotic protein bcl-2. Conclusionst-BHQ exerted potent anti-inflammatory effects in I/R-induced liver injury, and tBHQ would be a new effectively therapeutic measure for preventing hepatic I/R injury during liver surgery.

Protecting effects and mechanism of tert-butyl hydroquinone on retinal cells in type 2 diabetic rats

Background Apoptosis is a primary clinical pathological mechanism of diabetic retinopathy (DR). Oxidative stress and high glucose can activate cell apoptosis pathway and thus leads to cellular damage.It is confirmed that tert-butyl hydroquinone (tBHQ) plays an antioxidation effect, however, whether it has a protective role on retinal cells in DR is still unelucidated. Objective This study was to investigate the effect of tBHQ on vascular endothelial growth factor (VEGF) and bcl-2 expressions in retina of type 2 diabetic rats and its possible mechanism via nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) signal pathway. Methods Fifty clean healthy male SD rats were included in this experimental study.Ten rats were fed with normal diet as the normal control group, and other rats were fed with high fatty and high sugar food for 4 weeks.After 12 hours of fasting, streptozotoin (STZ) (30 mg/kg) was intraperitoneally injected to induce the type 2 diabetic models.The model rats were randomly divided into the diabetic control group and tBHQ group and 1% tBHQ was added into the high fatty and sugar food 1 week after modeling in the tBHQ group.Fasting plasma glucose (FPG) level, blood total cholesterol (TC) level, blood triglyceride (TG) level, high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C) and fasting serum insulin (FINs) were detected 4 and 12 weeks after modeling, respectively, and radio immunoassay was used to detect the FIN levels of the rats.The relative expression of VEGF and bcl-2 in retinas of the rats were assayed by immunohistochemistry and fluorescence real-time quantitative PCR (qRT-PCR). The use of the animals complied with the Regulations for the Administration of Affairs Concerning Experimental Animals by State and Technology Commission. Results Type 2 diabetic models were successfully established in 35 rats with successful rate 92.1%.The FIN levels were significantly different among different groups and time points (Fgroup=22.480, P=0.000; Ftime=7.636, P=0.008). The FPG, TC, TG and LDL-C levels were significantly different among the groups (FPG: Fgroup=78.531, P=0.000; TC: Fgroup=28.049, P=0.000; TG: Fgroup=13.108, P=0.000; LDL-C: Fgroup=6.804, P<0.05). Immunohistochemistry showed that VEGF and bcl-2 were mainly expressed in retinal ganglion cell layer, inner plexiform layer and outer plexiform layer.The expressions of VEGF and bcl-2 proteins were significantly different among different groups (VEGF: Fgroup=11.805, P=0.000; bcl-2: Fgroup=22.943, P=0.000); the expression level of bcl-2 protein was higher in 12 weeks after modeling than that in 4 weeks after modeling in the tBHQ group (P<0.05). The expressions of VEGF and Bcl-2 mRNA in rat retinas were significantly different among different groups and time points (VEGF: Fgroup=79.220, P=0.000; Ftime=6.090, P<0.05; Bcl-2: Fgroup=105.000, P=0.000; Ftime=13.170, P=0.001). Four and eight weeks after modeling, the expressions of VEGF and Bcl-2 mRNA in the diabetic control group and tBHQ group were significantly higher than that in the normal control group, and the expressions of Bcl-2 mRNA in the tBHQ group were significantly higher than that in the model control group (all at P<0.05); the expression of Bcl-2 mRNA was higher at 12 weeks after modeling than that at 4 weeks in the tBHQ group (P<0.05). Conclusions tBHQ produces anti-oxidative-damage and anti-apoptosis effects on retinal cells by up-regulating VEGF expression and down-regulating bcl-2 expression in DR rats.In addition, tBHQ may have effects on lowering high blood sugar, regulating insulin and blood lipid levels. Key words: Diabetes mellitus/complication; Retinopathy; Vascular endothelial growth factor; Bcl-2/metabolism; Disease models, animal; SD rats; Tert-butyl hydroquinone

The influence of tert-butyl hydroquinone on retinal nuclear factor E2-related factor 2 and heme oxygenase-1 in type 2 diabetic rats

Objective To observe the effect of tert-butyl hydroquinone (tBHQ) on type 2 diabetic rats retinal nuclear factor E2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1). Methods 60 Sprague Dawley rats were randomly divided into normal control group ( NC group, n=20) and model group (n=40). The rats in model group were intraperitoneal injected with streptozotocin (30 mg/kg) to establishing type 2 diabetic mellitus (DM). There were 35 rats successfully established and they were randomly divided into diabetic group (DM group, 17 rats) and tBHQ group (18 rats). The rats in tBHQ group were fed with high fat and sugar diet with 1% tBHQ. After 4 weeks and 12 weeks of tBHQ intervention, hematoxylin eosin staining of retinal sections, immunohistochemical staining and quantitative polymerase chain reaction (PCR) of Nrf2 and HO-1 were performed. Results In tBHQ control, the retina of rats was normal and individual cells showed slightly edema at 4 weeks; the retinal structure of rats was clear and part of cells showed edema at 12 weeks. At 4 and 12 weeks, the expression of Nrf2 (t=3.115, 3.781) and HO-1 (t=3.485, 3.785) protein in DM group were higher than that in NC group (P<0.05); the expression of Nrf2 (t=2.473, 2.576) and HO-1 (t=2.785, 2.879) protein in tBHQ group were higher than that in DM group (P<0.05). In DM group, the expression of Nrf2 protein at 12 weeks was higher than that at 4 weeks (t=0.276, P<0.05). In tBHQ group, the expression of Nrf2 (t=2.516) and HO-1 (t=2.776) protein at 12 weeks were higher than that at 4 weeks (P<0.05). 4 and 12 weeks, the expression of Nrf2 (t=4.758, 4.285) and HO-1 (t=5.114, 4.514) mRNA in DM group were higher than that in NC group (P<0.05); the expression of Nrf2 (t=5.133, 4.976) and HO-1 (t=4.758, 4.251) mRNA in tBHQ group were higher than that in DM group (P<0.05). In DM gruop, the expression of Nrf2 protein at 12 weeks was higher than that at 4 weeks (t=5.114, P<0.05). In tBHQ group, the expression of Nrf2 (t=4.292) and HO-1 (t=4.974) protein at 12 weeks were higher than that at 4 weeks (P<0.05). Conclusion tBHQ intervention can increased the expression of Nrf2, HO-1 significantly in the retina of type 2 diabetic rats. Key words: Diabetic retinopathy/physiopathology; NF-E2-related factor 2; Heme oxygenase (decyclizing); Animal experimentation

Role of Nrf2 signal pathway in rats with deep hypothermia ischemia/reperfusion injury undergoing remote postconditioning.

We investigated the protective effects of remote postconditioning (RPC) in the lungs of rats with deep hypothermia ischemia/reperfusion (I/R) injury and the role of nuclear factor E2-related factor 2 (Nrf2) signaling in this process. Forty-nine rats were randomly divided into a sham control group, deep hypothermia I/R group, RPC group, I/R+all-trans retinoic acid (ATRA) group, I/R+RPC+ATRA group, I/R+tert-butylhydroquinone (tBHQ) group, and I/R+RPC+tBHQ group. Real-time polymerase chain reaction and Western blot analysis were used to examine Nrf2 mRNA and protein expression, respectively. Compared with the sham control group, Nrf2 expression, malondialdehyde (MDA) content, and the wet/dry weight (W/D) ratio were significantly increased in the I/R group, while superoxide dismutase (SOD) activity was significantly decreased. Pulmonary Nrf2 expression and SOD activity was significantly increased, and MDA content and the W/D ratio were significantly decreased in the RPC group compared with the I/R group. Compared with the I/R group, MDA and W/D ratio significantly decreased and SOD activity remarkably increased in I/R+tBHQ group. After ATRA intervention in the I/R+ATRA group, MDA content and W/D ratio increased and SOD activity decreased compared to the I/R group. MDA content and W/D ratio in the RPC+tBHQ group significantly decreased and SOD activity increased compared with in the RPC group (P < 0.01). In the RPC+ATRA group, MDA content and W/D ratio decreased while SOD activity increased compared with the RPC group (P < 0.01). RPC alleviated deep hypothermia I/R injury; the Nrf2 signaling pathway may be involved in the protective effects induced by RPC.

Tert-butylhydroquinone alleviates early brain injury and cognitive dysfunction after experimental subarachnoid hemorrhage: role of Keap1/Nrf2/ARE pathway.

Tert-butylhydroquinone (tBHQ), an Nrf2 activator, has demonstrated neuroprotection against brain trauma and ischemic stroke in vivo. However, little work has been done with respect to its effect on early brain injury (EBI) after subarachnoid hemorrhage (SAH). At the same time, as an oral medication, it may have extensive clinical applications for the treatment of SAH-induced cognitive dysfunction. This study was undertaken to evaluate the influence of tBHQ on EBI, secondary deficits of learning and memory, and the Keap1/Nrf2/ARE pathway in a rat SAH model. SD rats were divided into four groups: (1) Control group (n = 40); (2) SAH group (n = 40); (3) SAH+vehicle group (n = 40); and (4) SAH+tBHQ group (n = 40). All SAH animals were subjected to injection of autologous blood into the prechiasmatic cistern once in 20 s. In SAH+tBHQ group, tBHQ was administered via oral gavage at a dose of 12.5 mg/kg at 2 h, 12 h, 24 h, and 36 h after SAH. In the first set of experiments, brain samples were extracted and evaluated 48 h after SAH. In the second set of experiments, changes in cognition and memory were investigated in a Morris water maze. Results shows that administration of tBHQ after SAH significantly ameliorated EBI-related problems, such as brain edema, blood-brain barrier (BBB) impairment, clinical behavior deficits, cortical apoptosis, and neurodegeneration. Learning deficits induced by SAH was markedly alleviated after tBHQ therapy. Treatment with tBHQ markedly up-regulated the expression of Keap1, Nrf2, HO-1, NQO1, and GSTα1 after SAH. In conclusion, the administration of tBHQ abated the development of EBI and cognitive dysfunction in this SAH model. Its action was probably mediated by activation of the Keap1/Nrf2/ARE pathway.

Pretreatment with tert-butylhydroquinone attenuates cerebral oxidative stress in mice after traumatic brain injury

BackgroundTraumatic brain injury (TBI) is a worldwide health problem, identified as a major cause of death and disability. Increasing evidence has shown that oxidative stress plays an important role in TBI pathogenesis. The antioxidant transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), is a known mediator in protection against TBI-induced brain damage. The objective of this study was to test whether tert-butylhydroquinone (tBHQ), a novel Nrf2 activator, can protect against TBI-induced oxidative stress. MethodsAdult male imprinting control region mice were randomly divided into three groups: (1) sham + vehicle group; (2) TBI + vehicle group; and (3) TBI + tBHQ group. Closed-head brain injury was applied using the Feeney weight-drop method. We accessed the neurologic outcome of mice at 24 h after TBI, and subsequently measured protein levels of Nrf2 and the NOX2 subunit of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase), the concentration of malondialdehyde, superoxide dismutase activity, and brain edema. ResultThe NOX2 protein level was increased fivefold in the TBI + vehicle group, whereas pretreatment with tBHQ markedly attenuated the NOX2 protein expression relative to that in the TBI + vehicle group. TBI increased Nrf2 formation by 5% compared with the sham group, whereas treatment with tBHQ further upregulated the Nrf2 protein level by 12% compared with the sham group. The level of the oxidative damage marker malondialdehyde was reduced by 29% in the TBI + tBHQ group compared with the TBI + vehicle group, Moreover, pretreatment with tBHQ significantly increased the antioxidant enzyme superoxide dismutase activity. Administration of tBHQ also significantly decreased TBI-induced brain edema and neurologic deficits. ConclusionsPretreatment with tBHQ effectively attenuated markers of cerebral oxidative stress after TBI, thus supporting the testing of tBHQ as a potential neuroprotectant and adjunct therapy for TBI patients.

Protective effect of tert-butylhydroquinone on cerebral inflammatory response following traumatic brain injury in mice

Aim Antioxidant transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) has been shown in our previous studies to play a crucial role in protection against TBI induced inflammatory response in the brain. The objective of this study was to test whether tert-butylhydroquinone (tBHQ), a novel Nrf2 activator, can protect mice brain against TBI-induced inflammatory damage. Methods Adult male ICR mice were randomly divided into three groups: (1) sham + vehicle group; (2) TBI + vehicle group; and (3) TBI + tBHQ group ( n = 12 per group). Closed head injury was adopted using Hall's weight-dropping method. We measured Nrf2 and nuclear factor kappa B (NF-κB) binding activities by electrophoretic mobility shift assay (EMSA), concentrations of tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) by enzyme-linked immunosorbent assay (ELISA), brain oedema by wet/dry weight method, and cortical apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) analysis. Results Induction of the Nrf2 activity by tBHQ markedly decreased NF-κB activation and inflammatory cytokine production in the injured brain. Administration of tBHQ also significantly attenuated TBI-induced brain oedema and cortical apoptosis. Conclusion Pre-treatment with tBHQ could attenuate the cerebral inflammatory response after TBI.

Effects of Tert-Butylhydroquinone on Intestinal Inflammatory Response and Apoptosis following Traumatic Brain Injury in Mice

Traumatic brain injury (TBI) can induce intestinal inflammatory response and mucosal injury. Antioxidant transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) has been shown in our previous studies to prevent oxidative stress and inflammatory response in gut after TBI. The objective of this study was to test whether tert-butylhydroquinone (tBHQ), an Nrf2 inducer, can protect against TBI-induced intestinal inflammatory response and mucosal injury in mice. Adult male ICR mice were randomly divided into three groups: (1) sham + vehicle group, (2) TBI + vehicle group, and (3) TBI + tBHQ group (n = 12 per group). Closed head injury was adopted using Hall's weight-dropping method. Intestinal mucosa apoptosis and inflammatory-related factors, such as nuclear factor kappa B (NF-κB), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and intercellular adhesion molecule-1 (ICAM-1), were investigated at 24 h after TBI. As a result, we found that oral treatment with 1% tBHQ prior to TBI for one week markedly decreased NF-κB activation, inflammatory cytokines production, and ICAM-1 expression in the gut. Administration of tBHQ also significantly attenuated TBI-induced intestinal mucosal apoptosis. The results of the present study suggest that tBHQ administration could suppress the intestinal inflammation and reduce the mucosal damage following TBI.