Effects of CuSO4 on hepatic mitochondrial function, biogenesis and dynamics in mice.

Copper is an essential trace element for animal. Excessive intake of copper will cause a large accumulation of copper in the body, especially in the liver, and induce hepatotoxicity, however, there are few studies on the effects of copper on hepatic mitochondrial biogenesis and mitochondrial dynamics. In this study, mice were treated with different doses of CuSO4 (0, 10, 20, and 40 mg/kg) for 21 and 42 days by gavage. The results verified that CuSO4 decreased the content of mitochondrial respiratory chain complexes I-IV in mouse liver. CuSO4 treatment resulted the decrease in the protein and mRNA expression levels of PGC-1α, TFAM, and NRF1, which were the mitochondrial biogenesis regulator proteins. Meanwhile, the proteins involved in mitochondrial fusion were reduced by CuSO4 , such as Mfn1 and Mfn2, however, mitochondrial fission proteins Drip1 and Fis1 were significantly increased. Abovementioned results show that CuSO4 could induce mitochondria damage in the liver of mice, and mitochondrial biogenesis and mitochondrial dynamics are involved in the molecular mechanism of CuSO4 -induced hepatotoxicity.

Apoptosis and DNA damage mediated by ROS involved in male reproductive toxicity in mice induced by Nickel.

Nickel (Ni) is the most important environmental pollution in the world. Ni has been confirmed to have multi-organ toxicology and carcinogenicity. Recently, Ni also can impair the male reproductive system, however, its precious mechanism still has not been clarified. The current work found that nickel chloride (NiCl2) induced histopathological lesions in testis. And, the Johnsen's score, seminiferous tubule diameter, and spermatogenic epithelium thickness were decreased in NiCl2-treated mice. The number of spermatogonium, primary spermatocyte, and round spermatid also were significantly reduced after Ni treatment. Next the potential molecular mechanism was measured. NiCl2 treatment elevated ROS production in the testis. Additionally, NiCl2 was found to induce apoptosis with features including up-regulation of Bax, cleaved-caspase-3, cleaved-caspase-8, caspase-9, and caspase-12, while down-regulation of Bcl-2 expression. In the meantime, the marker protein of DNA damage γ-H2AX was significantly increased in NiCl2-primed mice testis. To clarify effects of reactive oxygen species (ROS) in apoptosis and DNA damage induced by NiCl2, NiCl2 was used to co-treat antioxidant NAC (N-Acetyl-L-cysteine). NAC weakened ROS production induced by NiCl2, and played an inhibition role in apoptosis and DNA damage. Moreover, co-treatment using NiCl2 and NAC group also eliminated spermatogenesis disorders. In summary, research results reveal the relations of spermatogenesis disorder induced by NiCl2 with apoptosis and DNA damage mediated by ROS and apoptosis in the testis.

Autophagy-mediated ferroptosis involved in nickel-induced nephrotoxicity in the mice.

Nickel, as a widely polluted metal, has been shown nephrotoxicity. Ferroptosis is a new type of cell death driven by iron-dependent lipid peroxidation. Our study found that nickel chloride (NiCl2) induced ferroptosis in mouse kidney and TCMK-1 cells. The iron content was significantly increased in the kidney and TCMK-1 cells after NiCl2 treatment. Lipid peroxidation and MDA content were significantly increased, and GSH content and T-SOD activity were significantly decreased after exposure to NiCl2. Moreover, NiCl2 increased COX-2 protein levels, decreased SLC7A11 and GPX4 protein levels, and elevated Ptgs2 mRNA levels. Next, the mechanism of Ni-induced ferroptosis was investigated. The results showed that NiCl2 induced autophagy in TCMK-1 cells, which promoted ferroptosis induced by NiCl2. Furthermore, the data of autophagy activation or inhibition experiment showed that autophagy facilitated ferroptosis through the degradation of the iron regulation protein NCOA4 and FTH1. Otherwise, iron chelator DFOM treatment inhibited ferroptosis induced by NiCl2. Finally, ferroptosis inhibitor Fer-1 treatment significantly alleviated cytotoxicity induced by NiCl2. To sum up, our above results showed that ferroptosis is involved in NiCl2-induced nephrotoxicity, and NiCl2 induces autophagy-dependent ferritin degradation, releases iron ions, leads to iron overload, and induces ferroptosis. This study supplies a new theoretical foundation for the study of nickel and renal toxicity.

Nickel induces hepatotoxicity by mitochondrial biogenesis, mitochondrial dynamics, and mitophagy dysfunction.

Nickel (Ni) is an important and widely hazardous chemical industrial waste. Excessive Ni exposure could cause multi-organs toxicity in human and animals. Liver is the major target organ of Ni accumulation and toxicity, however, the precise mechanism is still unclear. In this study, nickel chloride (NiCl2 )-treatment induced hepatic histopathological changes in the mice, and, transmission electron microscopy results showed mitochondrial swollen and deformed of hepatocyte. Next, the mitochondrial damages including mitochondrial biogenesis, mitochondrial dynamics, and mitophagy were measured after NiCl2 administration. The results showed that NiCl2 suppressed mitochondrial biogenesis by decreasing PGC-1α, TFAM, and NRF1 protein and mRNA expression levels. Meanwhile, the proteins involved in mitochondrial fusion were reduced by NiCl2 , such as Mfn1 and Mfn2, however, mitochondrial fission proteins Drip1 and Fis1 were significantly increased. The up-regulation of mitochondrial p62 and LC3II expression indicated that NiCl2 increased mitophagy in the liver. Moreover, the receptor-mediated mitophagy and ubiquitin (Ub)-dependent mitophagy were detected. NiCl2 promoted PINK1 accumulation and Parkin recruitment on mitochondria. And, the receptor proteins of mitophagy Bnip3 and FUNDC1 were increased in the NiCl2 -treated mice liver. Overall, these results show that NiCl2 could induce mitochondria damage in the liver of mice, and, dysfunction of mitochondrial biogenesis, mitochondrial dynamics and mitophagy involved in the molecular mechanism of NiCl2 -induced hepatotoxicity.

Low Glucose plus ß-Hydroxybutyrate Induces an Enhanced Inflammatory Response in Yak Alveolar Macrophages via Activating the GPR109A/NF-κB Signaling Pathway.

Yaks are often subject to long-term starvation and a high prevalence of respiratory diseases and mortality in the withered season, yet the mechanisms that cause this remain unclear. Research has demonstrated that ß-hydroxybutyrate (BHB) plays a significant role in regulating the immune system. Hence, we hypothesize that the low glucose and high BHB condition induced by severe starvation might have an effect on the pro-inflammatory response of the alveolar macrophages (AMs) in yaks. To validate our hypothesis, we isolated and identified primary AMs from freshly slaughtered yaks and cultured them in a medium with 5.5 mM of glucose or 2.8 mM of glucose plus 1-4 mM of BHB. Utilizing a real-time quantitative polymerase chain reaction (RT-qPCR), immunoblot assay, and enzyme-linked immunosorbent assay (ELISA), we evaluated the gene and protein expression levels of GPR109A (G-protein-coupled receptor 109A), NF-κB p65, p38, and PPARγ and the concentrations of pro-inflammatory cytokines interleukin (IL)-1ß and IL-6 and tumor necrosis factor (TNF)-α in the supernatant. The results demonstrated that AMs exposed to low glucose plus BHB had significantly higher levels of IL-1ß, IL-6, and TNF-α (p < 0.05) and higher activity of the GPR109A/NF-κB signaling pathway. A pretreatment of either pertussis toxin (PTX, inhibitor of GPR109A) or pyrrolidinedithiocarbamic (PDTC, inhibitor of NF-κB p65) was effective in preventing the elevated secretion of pro-inflammatory cytokines induced by low glucose plus BHB (p < 0.05). These results indicated that the low glucose plus BHB condition would induce an enhanced pro-inflammatory response through the activation of the GPR109A/NF-κB signaling pathway in primary yak AMs, which is probably the reason why yaks experience a higher rate of respiratory diseases and mortality. This study will offer new insight into the prevention and treatment of bovine respiratory diseases.

RAGE-TLR4 Crosstalk Is the Key Mechanism by Which High Glucose Enhances the Lipopolysaccharide-Induced Inflammatory Response in Primary Bovine Alveolar Macrophages.

The receptor of advanced glycation end products (RAGE) and Toll-like receptor 4 (TLR4) are important receptors for inflammatory responses induced by high glucose (HG) and lipopolysaccharide (LPS) and show crosstalk phenomena in inflammatory responses. However, it is unknown whether RAGE and TLR4 can influence each other's expression through a crosstalk mechanism and whether the RAGE-TLR4 crosstalk related to the molecular mechanism of HG enhances the LPS-induced inflammatory response. In this study, the implications of LPS with multiple concentrations (0, 1, 5, and 10 µg/mL) at various treatment times (0, 3, 6, 12, and 24 h) in primary bovine alveolar macrophages (BAMs) were explored. The results showed that a 5 µg/mL LPS treatment at 12 h had the most significant increment on the pro-inflammatory cytokine interleukin 1ß (IL-1ß), IL-6, and tumor necrosis factor (TNF)-α levels in BAMs (p < 0.05) and that the levels of TLR4, RAGE, MyD88, and NF-κB p65 mRNA and protein expression were upregulated (p < 0.05). Then, the effect of LPS (5 µg/mL) and HG (25.5 mM) co-treatment in BAMs was explored. The results further showed that HG significantly enhanced the release of IL-1ß, IL-6, and TNF-α caused by LPS in the supernatant (p < 0.01) and significantly increased the levels of RAGE, TLR4, MyD88, and NF-κB p65 mRNA and protein expression (p < 0.01). Pretreatment with FPS-ZM1 and TAK-242, the inhibitors of RAGE and TLR4, significantly alleviated the HG + LPS-induced increment of RAGE, TLR4, MyD88, and NF-κB p65 mRNA and protein expression in the presence of HG and LPS (p < 0.01). This study showed that RAGE and TLR4 affect each other's expression through crosstalk during the combined usage of HG and LPS and synergistically activate the MyD88/NF-κB signaling pathway to promote the release of pro-inflammatory cytokines in BAMs.

The combination of high glucose and LPS induces autophagy in bovine kidney epithelial cells via the Notch3/mTOR signaling pathway.

BACKGROUND: Aside respiratory diseases, beef cattle may also suffer from serious kidney diseases after transportation. Hyperglycemia and gram-negative bacterial infection may be the main reasons why bovine is prone to severe kidney disease during transportation stress, however, the precise mechanism is still unclear. The purpose of the current study is to explore whether the combined treatment of high glucose (HG) and lipopolysaccharide (LPS) could induce madin-darby bovine kidney (MDBK) cells injury and autophagy, as well as investigate the potential molecular mechanisms involved. RESULTS: As we discovered, the combined effect of HG and LPS decreased MDBK cells viability. And, HG and LPS combination also induced autophagy in MDBK cells, which was characterized by increasing the expression of LC3-II/I and Beclin1 and decreasing p62 expression. LC3 fluorescence signal formation was also significantly increased by HG and LPS combination treatment. Furthermore, we measured whether the mammalian target of rapamycin (mTOR) and the Notch3 signaling pathways were involved in HG and LPS-induced autophagy. The results showed that the combination of HG and LPS significantly increased the protein expression of Notch3 and decreased protein expression of p-mTOR, indicating that Notch3 and mTOR signaling pathways were activated. However, co-treatment with the Notch3 inhibitor (DAPT) could reverse the induction of autophagy, and increased the protein expression of p-mTOR. CONCLUSIONS: This study demonstrated that the combination effect of HG and LPS could induce autophagy in MDBK cells, and the Notch3/mTOR signaling pathway was involved in HG and LPS-induced autophagy.

Sodium fluoride suppresses spleen development through MAPK/ERK signaling pathway in mice.

Numerous studies have documented that excessive fluoride intake could cause pathological damage and functional disorder in organisms. Nevertheless, the systemic mechanism of fluorosis inhibiting the proliferation and development of splenic cell is still scarce. The preliminary studies have confirmed that high-dose NaF could inhibit splenic lymphocytes proliferation in vitro and cause toxic effects on spleen development in vivo. Here this study continued to explore the signaling pathway with the methods of quantitative real-time polymerase chain reaction (qRT-PCR) and western blot (WB), revealing the mechanism of fluorosis in the growth system. Mice in 4 groups (control, 12 mg/kg, 24 mg/kg, 48 mg/kg) were gavage administrated with NaF solution continuously for 42 days. The results suggested that NaF more than 12 mg/kg slowed down the growth of mice, inhibited spleen growth and development, which was characterized by decreasing spleen volume, and inducing splenic cell apoptosis. For the Ras-Raf-MEK-ERK signaling pathway, the mRNA and protein expression levels of Ras were significantly elevated, and the phosphorylated protein expression levels of Raf (B-Raf, C-Raf) were increased. Meanwhile, mice mRNA expression levels were increased in a time and dose-dependent manner on the 21st and 42nd days of the experiment. Additionally, the mRNA and protein levels of MEK1/2 were increased on the 21st day of the experiment, while reduced on the 42nd day. The ERK1/2 levels were significantly decreased at both 21st and 42nd days of the experiment. This study showed that NaF activated Ras to induce downstream Raf-MEK-ERK cascade reaction, but failed to activate ERK eventually, the proliferation signal from the cell surface could not transmit to the nucleus, interfering with the regulation of cell proliferation, differentiation, meiosis, and suppressed spleen development ultimately.

Autophagy and apoptosis mediated nano-copper-induced testicular damage.

Nano-copper has been increasingly employed in various products. In previous studies, we showed that nano-copper caused damage in the rat testis, but it remains unclear whether the toxic reaction can affect the reproductive function. In this study, following 28 d of exposure to nano-copper at a dose of 44, 88, and 175 mg/kg/day, there was a decrease in sperm quality, fructose content, and the secretion of sex hormones. Nano-copper also increased the level of oxidative stress, sperm malformation rate, and induced abnormal structural changes in testicular tissue. Moreover, Nano-copper upregulated the expression of apoptosis-related protein Bax and autophagy-related protein Beclin, and downregulated the expression of Bcl2 and p62. Furthermore, nano-copper (175 mg/kg) downregulated the protein expression of AMPK, p-AKT, mTOR, p-mTOR, p-4E-BP1, p70S6K, and p-p70S6K, and upregulated the protein expression of p-AMPK. Therefore, nano-copper induced damage in testicular tissues and spermatogenesis is highly related to cell apoptosis and autophagy by regulating the Akt/mTOR signaling pathway. In summary, excess exposure to nano-copper may induce testicular apoptosis and autophagy through AKT/mTOR signaling pathways, and damage the reproductive system in adult males, which is associated with oxidative stress in the testes.

Notch3-Mediated mTOR Signaling Pathway Is Involved in High Glucose-Induced Autophagy in Bovine Kidney Epithelial Cells.

It is reported that Notch3 and mTOR signaling pathways are involved in autophagy, and both can be activated by high glucose (HG). However, the relationship between Notch3 and mTOR and how Notch3 affects mTOR to regulate HG-induced autophagy in bovine kidney epithelial cells is still unclear. The purpose of this study is to explore how Notch3 affects mTOR to modulate HG-induced autophagy in bovine kidney cells. Our results showed that HG treatment significantly decreased the cell viability of MDBK cells in a dose-dependent manner. HG treatment significantly increased the expression of LC3-II/I ratio and Beclin1 protein and significantly decreased the expression of p62 protein. Consistently, LC3 fluorescence signal formation was detected by immunofluorescence in both dose and time-dependent manners. In addition, HG treatment significantly increased the expression of Notch3 protein and decreased the expression of the p-mTOR protein in both dose and time-dependent manners. Inhibition of Notch3 upregulated the expression of p-mTOR and p62 protein, and downregulated the expression of LC3-II/I ratio and Beclin1 protein. Besides, the function of Notch3 was investigated. In this study, inhibition of Notch3 activity significantly increased the viability of HG-stimulated MDBK cells. In summary, our results revealed that the Notch3-mediated mTOR signaling pathway was involved in HG-induced autophagy in MDBK cells.

TGF-ß1-induced EMT activation via both Smad-dependent and MAPK signaling pathways in Cu-induced pulmonary fibrosis.

Copper (Cu) is considered as an essential trace element for living organisms. However, over-exposure to Cu can lead to adverse health effects on human and animals. There are limited researches on pulmonary toxicity induced by Cu. Here, we found that copper sulfate (CuSO4)-treatment could induce pulmonary fibrosis with Masson staining and up-regulated protein and mRNA expression of Collagen I and α-Smooth Muscle Actin (α-SMA) in mice. Next, the mechanism underlying Cu-induced pulmonary fibrosis was explored, including transforming growth factor-ß1 (TGF-ß1)-mediated Smad pathway, mitogen-activated protein kinases (MAPKs) pathway and epithelial-mesenchymal transition (EMT). CuSO4 triggered pulmonary fibrosis by activation of the TGF-ß1/Smad pathway, which was accomplished by increasing TGF-ß1, p-Smad2 and p-Smad3 protein and mRNA expression levels. Also, up-regulated protein and mRNA expression of p-JNK, p-ERK, and p-p38 demonstrated that CuSO4 activated MAPKs pathways. Concurrently, EMT was activated by increasing vimentin and N-cadherin while decreasing E-cadherin protein and mRNA expression levels. Altogether, the abovementioned findings indicate that CuSO4 treatment may induce pulmonary fibrosis through the activation of EMT induced by TGF-ß1/Smad pathway and MAPKs pathways, revealing the mechanism Cu-caused pulmonary toxicity.

Copper induces hepatocyte autophagy via the mammalian targets of the rapamycin signaling pathway in mice.

Although copper is among the indispensable trace elements in animal physiological processes, it exerts toxicity upon over-exposure. The present study aimed to investigate hepatocyte autophagy induced by CuSO4 and its potential mechanism. A total of 240 ICR mice (four-week-old, 120 males and 120 females) were randomly divided into four groups, in which mice separately received 0, 4, 8, and 16 mg/kg of Cu (Cu2+-CuSO4) for 42 d. The results of increased autophagosomes and autophagy marker LC3B brown cell staining showed that excessive intake of Cu enhanced hepatocyte autophagy. Simultaneously, Cu inhibited the activity of mTOR through suppressing mRNA and protein expressions in mTOR, which in turn up-regulated expression levels of ULK1 and initiated autophagy. Also, over-exposure to Cu increased mRNA and protein expressions of Beclin1, Atg12, Atg5, Atg16L1, Atg7, Atg3, and LC3 and decreased mRNA and protein expressions of p62. These results indicate that excess Cu can enhance hepatocyte autophagy via inhibiting the mTOR signaling pathway and regulating mRNA and protein expressions of factors implicated to autophagy in mice.

Vitamin E protects against cadmium-induced sub-chronic liver injury associated with the inhibition of oxidative stress and activation of Nrf2 pathway.

Hepatic oxidative stress, as one important mechanism of cadmium (Cd)-induced hepatic toxicity, could, as known, be ameliorated by vitamin E (VE). However, the underlying mechanism remains to be elucidated. To investigate whether the antioxidant vitamin E can protect against Cd-induced sub-chronic liver injury associated with oxidative stress and nuclear factor erythrocyte 2-related factor 2 (Nrf2) pathway, male Sprague-Dawley rats (nine-week-old) were randomly divided into four groups (eight rats/group), namely, control, VE (100 mg/kg VE), Cd (5 mg/kg CdCl2) and VE+Cd (100 mg/kg VE+5 mg/kg CdCl2), and received intragastric administration of Cd and/or VE for four weeks. Cd-exposure alone resulted in reduced liver weight, liver histological alteration and oxidative stress, accumulation of Cd in the liver, elevated ALT and AST concentrations in serum together with decreased mRNA and protein expressions of Nrf2 pathway related molecules (Nrf2, HO-1, NQO-1, GCLC, GCLM and GST). However, the co-treatment of Cd and VE significantly ameliorated the changes mentioned above, and promoted the expression of genes and proteins of Nrf2 pathway related molecules in comparison to the Cd-exposure alone. Our results indicate that the protective effect of VE against Cd-induced sub-chronic hepatic damage in rats is associated with the inhibition of oxidative stress and activation of Nrf2 pathway.

Nickel chloride induces spermatogenesis disorder by testicular damage and hypothalamic-pituitary-testis axis disruption in mice.

As a common environmental pollutant, nickel chloride (NiCl2) poses serious threat to human and animals health. NiCl2 has adverse effects on reproductive function in male, however, the underlying mechanisms are not fully illuminated. In this study, 64 male ICR mice were divided into four groups (8 mice per each period/ group), in which mice orally administrated with 0, 7.5, 15 or 30 mg/kg body weight for 14 or 28 consecutive days, respectively. The results showed that the sperm concentration (12.95%, 29.78% and 37.63% -) and sperm motility (19.79%, 34.88% and 43.10%) were dose-dependent significantly reduced, and the total sperm malformation rates (110.15%, 206.84% and 292.27%) were dose-dependent significantly elevated in the 7.5, 15 and 30 mg/kg NiCl2 treatment groups (vs control at 28 days), respectively (P < 0.05). Meanwhile, NiCl2 also decreased the relative weights of testis and epididymis and caused histopathological lesions of testis and epididymis. Furthermore, serum testosterone levels were significantly decreased after NiCl2 treatment. And the findings showed that NiCl2 down-regulated the expression of LH-R, StAR, P450scc, 3ß-HSD, 17ß-HSD, ABP and INHßB in the testis, however, the relative genes in the hypothalamus (Kiss-1, GPR54 and GnRH) and pituitary (GnRH-R, LHß and FSHß) did not exhibit noticeable change. In summary, NiCl2 induced spermatogenesis disorder by testicular damage and hypothalamic-pituitary-testis axis disruption in mice, and only impaired the genes on the testis of HPT axis.

Copper exposure induces hepatic G0/G1 cell-cycle arrest through suppressing the Ras/PI3K/Akt signaling pathway in mice.

Copper (Cu), as a common chemical contaminant in environment, is known to be toxic at high concentrations. The current research demonstrates the effects of copper upon hepatocyte cell-cycle progression (CCP) in mice. Institute of cancer research (ICR) mice (n = 240) at an age of four weeks were divided randomly into groups treated with different doses of Cu (0, 4, 8, and 16 mg/kg) for 21 and 42 days. Results showed that high Cu exposure caused hepatocellular G0/G1 cell-cycle arrest (CCA) and reduced cell proportion in the G2/M phase. G0/G1 CCA occurred with down-regulation (p < 0.05) of Ras, p-PI3K (Tyr458), p-Akt (Thr308), p-forkhead box O3 (FOXO3A) (Ser253), p-glycogen synthase kinase 3-ß (GSK3-ß) (Ser9), murine double minute 2 (MDM2) protein, and mRNA expression levels, and up-regulation (p < 0.05) of PTEN, p-p53 (Ser15), p27, p21 protein, and mRNA expression levels, which subsequently suppressed (p < 0.05) the protein and mRNA expression levels of CDK2/4 and cyclin E/D. These results indicate that Cu exposure suppresses the Ras/PI3K/Akt signaling pathway to reduce the level of CDK2/4 and cyclin E/D, which are essential for the G1-S transition, and finally causes hepatocytes G0/G1 CCA.

Nickel induces autophagy via PI3K/AKT/mTOR and AMPK pathways in mouse kidney.

Nickel (Ni), a widely distributed metal, is an important pollutant in the environment. Although kidney is a crucial target of Ni toxicity, information on autophagy and the potential mechanisms of Ni-induced renal toxicity are still poorly described. As we discovered, NiCl2 could induce renal damage including decrease in renal weight, renal histological alterations, and renal function injury. According to the obtained results, NiCl2 could obviously increase autophagy, which was characterized by increase of LC3 expression and decrease of p62 expression. Meanwhile, the result of ultrastructure observation showed increased autolysosomes numbers in the kidney of NiCl2-treated mice. In addition, NiCl2 increased mRNA and protein levels of autophagy flux proteins including Beclin1, Atg5, Atg12, Atg16L1, Atg7, and Atg3. Furthermore, NiCl2 induced autophagy through AMPK and PI3K/AKT/mTOR pathways which featured down-regulated expression levels of p-PI3K, p-AKT and p-mTOR and up-regulated expression levels of p-AMPK and p-ULK1. In summary, the above results indicate involvement of autophagy in renal injury induced by NiCl2, and NiCl2 induced autophagy via PI3K/AKT/mTOR and AMPK pathways in mouse kidney.

Attenuated Cardiac oxidative stress, inflammation and apoptosis in Obese Mice with nonfatal infection of Escherichia coli.

Obesity is a risk factor of many diseases, but could be beneficial to the individuals with bacterial infection. The present study was conducted to investigate the relationship between obesity and heart during nonfatal bacterial infection. Male normal (lean) and diet-induced obesity mice (DIO, fed with high-fat diet) were chosen to perform nasal instillation with E. coli to establish a nonfatal acute mouse model. The cardiac histopathology, inflammation and oxidative damage, as well as apoptosis were detected post-infection. The results revealed that the Escherichia coli (E.coli)-infected mice exhibited increased cardiac index, contents of IL-1ß, IL-6, IL-8, TNF-α, leptin and resistin, levels of apoptotic proteins (caspase-3 and caspase-9, and bax/bcl-2 ratio), cardiac pathological changes and oxidative stress. Furthermore, these parameters were more serious in the lean mice than those in the DIO mice. In summary, our findings gave a new sight that E.coli infection impaired heart via histopathological lesions, inflammation and oxidative stress and excessive apoptosis of cardiomyocytes. Interestingly, obesity exerted attenuated effects on the heart of mice with non-fatal infection of E.coli through decreased inflammation, oxidative stress and apoptosis of cardiac tissue.

Oxidative stress-mediated apoptosis and autophagy involved in Ni-induced nephrotoxicity in the mice.

As an extensively environmental pollution, Nickel (Ni) represents a serious hazard to human health. The present study focused on exploring the mechanism of Ni-mediated nephrotoxicity, such as apoptosis, autophagy and oxidative stress. In the current work, NiCl2 treatment could induce kidney damage. Meanwhile, NiCl2 treatment elevated ROS production and MDA content and suppressed the antioxidant activity, which was characterized by reducing T-AOC, CAT, SOD activity and GSH content. For investigating the role of oxidative stress on NiCl2-mediated nephrotoxicity, N-acetyl cysteine (NAC, effective antioxidant and free radical scavenger) was co-treated with NiCl2. The results showed that NAC significantly suppressed the NiCl2-mediated oxidative stress and mitigated NiCl2-induced the kidney damage. Then, whether oxidative stress-induced autophagy and apoptosis were involved in NiCl2-induced nephrotoxicity was explored. The findings demonstrated that NAC relieved NiCl2-induced autophagy and reversed the activation of Akt/AMPK/mTOR pathway. Concurrently, the results indicated that NAC attenuated NiCl2-induced apoptosis, as evidenced by reduction of apoptotic cells and cleaved-caspase-3/- 8/- 9 together with cleaved-PARP protein levels. To sum up, our findings suggested that NiCl2-mediated renal injury was associated with oxidative stress-induced apoptosis and autophagy. This study provides new theoretical basis for excess Ni exposure nephrotoxic researches.

Copper induces hepatic inflammatory responses by activation of MAPKs and NF-κB signalling pathways in the mouse.

The present study investigated the expressions of signalling molecules and inflammatory cytokines involved in copper-induced inflammatory responses of the mouse liver. A total of 240 institute of cancer research (ICR) mice (half male and half female) aged four weeks were randomly allocated to four groups treated with 0, 4, 8, and 16 mg/kg of [Cu] (Cu2+-CuSO4) for 42 days, respectively. [Cu] exceeding 4 mg/kg was found to induce inflammatory responses of the liver. Results showed significant up-regulation of mRNA and protein levels of apoptosis signal-regulating kinase 1 (ASK1), mitogen-activated protein kinase kinases 3/6 (MEK3/6), c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (p38 MAPK), mitogen-activated protein kinase kinases 4/7 (MEK4/7), mitogen-activated protein kinase kinases 1/2 (MEK1/2), and extracellular signal-regulated protein kinases 1/2 (Erk1/2) due to Cu. By doing so, copper could activate the mitogen-activated protein kinases (MAPKs) signalling pathway. Concurrently, the nuclear factor-kappa B (NF-κB) signalling pathway was also activated in the Cu-treatment, as demonstrated by higher expressions of NF-κB and cyclooxygenase-2 (COX-2), activities of inducible nitric oxide synthase (iNOS), contents of nitric oxide (NO) and prostaglandin E2 (PGE2), and reducing levels of expression of inhibitory kappa B (IκB). High Cu intake also up-regulated expression levels of some pro-inflammatory mediators such as interleukin-2 (IL-2), interleukin-1ß (IL-1ß), and interleukin-8 (IL-8), and down-regulated the levels of expression of transforming growth factor beta (TGF-ß), an anti-inflammatory mediator. Additionally, our results indicated that Cu caused hepatic dysfunction, with evidence of occurrence of histopathological lesions and higher serum activities of alkaline phosphatase (AKP), aspartic acid transferase (AST), alanine amino transferase (ALT), and gamma-glutamyl transpeptidase (GGT), contents of albumin (ALB) and total bilirubin (TBIL). Altogether, the aforementioned results indicate that [Cu], at more than 4 mg/kg, induces the inflammatory responses in the liver via NF-κB and MAPKs signalling pathways, subsequently inducing hepatic dysfunction.

Copper sulfate-induced endoplasmic reticulum stress promotes hepatic apoptosis by activating CHOP, JNK and caspase-12 signaling pathways.

Copper (Cu), a transition metal, is an essential trace element in human and animal nutrition at low concentration, but Cu has toxic effects on tissues and organs at high concentration. Endoplasmic reticulum (ER) is a toxicological target in Cu poison. Thus far, no studies have focused on the relationship among copper, endoplasmic reticulum (ER) stress and apoptosis in animal and human livers. In the present study, mice treated with copper sulfate (CuSO4) were used to assess the impacts of copper on ER stress and hepatic apoptosis. A total of 240 mice were orally administered with 0 (control), 10, 20 and 40 mg/kg of CuSO4 for 42 days. The results indicated that CuSO4 at 10 mg/kg markedly induced hepatocyte apoptosis and ER stress. In addition, ER stress was characterized by the increased mRNA and protein levels of glucose-regulated protein 78 (GRP78) and 94 (GRP94). Furthermore, ER stress-triggered 3 apoptotic pathways were also activated by the increased intracellular calcium and up-regulated expression levels of genes involved in growth arrest- and DNA damage-inducible gene 153 (Gadd153/CHOP), c-Jun N-terminal kinase (JNK) and cysteine aspartate-specific protease 12 (caspase-12) signaling pathways in CuSO4-treated mice. In conclusion, CuSO4-induced ER stress can promote hepatic apoptosis in mice by activating CHOP, JNK and caspase-12 signaling pathways.