Tert-butylhydroquinone attenuates LPS-induced pyroptosis of IPEC-J2 cells via downregulating HMGB1/TLR4/NF-κB axis.

Inflammatory response induced by biological stress usually occurs in weaning piglets, it reduces the production performance of piglets and even causes death. Tert-butylhydroquinone (TBHQ) is a food additive that has the effect of anti-inflammation and anti-oxidation. However, there are few reports related to the protective mechanisms of TBHQ on lipopolysaccharide (LPS) induced injury in intestinal porcine epithelial (IPEC-J2) cells. Quantitative real-time polymerase chain reaction and western blot analysis, respectively, detected the mRNA levels and protein expressions related to pyroptosis, tight junction (TJ) protein and high-mobility group box 1/toll-like receptor 4/nuclear factor kappa-B (HMGB1/TLR4/NF-κB) axis. Localisation and expression of NOD-like receptor pyrin domain containing 3 (NLRP3), HMGB1 and P-NF-κB proteins detected by immunofluorescence. The results showed that TBHQ (12.5 and 25 µM) can increase cell activity and reduce intracellular lactate dehydrogenase (LDH) levels in a dose-dependent manner. LPS significantly decreases cell viability and increases the LDH level. However, pretreatment with TBHQ evidently increases cell viability and decreases the LDH level of IPEC-J2 cells. In addition, treatment with LPS decreased the mRNA level and protein expression of zonula occludens-1, occludin and claudin-1, and increased the mRNA level and protein expression of pyroptosis and HMGB1/TLR4/NF-κB axis. Interestingly, pretreatment with TBHQ increased the TJ protein expressions as well as decreased the mRNA level and protein expressions of pyroptosis and HMGB1/TLR4/NF-κB axis. Moreover, the results of immunofluorescence showed that TBHQ significantly reduced the expression of NLRP3, HMGB1 and P-NF-κB in LPS-induced injury of IPEC-J2 cells. Therefore, we come to the conclusion that TBHQ attenuates LPS-induced pyroptosis in IPEC-J2 cells through downregulation of the HMGB1/TLR4/NF-κB axis, TBHQ may become a potential feed additive for preventing inflammatory diarrhoea in piglets.

Asiatic Acid Alleviates Lipopolysaccharide-Induced Acute Myocardial Injury by Promoting Mitophagy and Regulating Mitochondrial Dynamics in Broilers.

Acute myocardial injury (AMI) induced by lipopolysaccharide (LPS) can cause cardiovascular dysfunction and lead to death in poultry. Traditional antibiotic therapy has been found to have many limitations and negative effects. Asiatic acid (AA) is a naturally occurring pentacyclic triterpenoid that is extracted from Centella asiatica and has anti-inflammatory, antioxidant, and anticancer pharmacological properties. Previously, we studied the effect of AA on LPS-induced liver and kidney injury; however, the impact of AA on LPS-induced AMI remained unclear. Sixty 1-day-old broilers were randomly divided into control group, LPS group, LPS + AA 15 mg/kg group, LPS + AA 30 mg/kg group, LPS + AA 60 mg/kg group, and control + AA 60 mg/kg group. The histopathology of cardiac tissues was detected by hematoxylin and eosin (H&E) staining. The mRNA and protein expressions related to mitochondrial dynamics and mitophagy were detected by quantitative real-time PCR, western blot, immunofluorescence, and immunohistochemistry. Disorganized myocardial cells and fractured myocardial fibers were found in the LPS group, and obvious red-blood-cell filling can be seen in the gaps between the myocardial fibers in the low-dose AA group. Nevertheless, the medium and high dose of AA obviously attenuated these changes. Our results showed that AA significantly restored the mRNA and protein expressions related to mitochondrial dynamic through further promoting mitophagy. This study revealed the effect of AA on LPS-induced AMI in broilers. Mechanically, AA regulated mitochondrial dynamic homeostasis and further promoted mitophagy. These novel findings indicate that AA may be a potential drug for LPS-induced AMI in broilers.

El ácido asiático como mitigante de las lesiones miocárdicas agudas inducidas por lipopolisacáridos al promover la mitofagia y regular la dinámica mitocondrial en pollos de engorde. La lesión miocárdica aguda (con siglas en inglés IAM) inducida por lipopolisacáridos (LPS) puede causar disfunción cardiovascular y provocar la muerte en las aves comerciales. Se ha descubierto que la terapia tradicional con antibióticos tiene muchas limitaciones y efectos negativos. El ácido asiático (AA) es un triterpenoide pentacíclico natural que se extrae de la planta Centella asiática y que tiene propiedades farmacológicas antiinflamatorias, antioxidantes y anticancerígenas. Anteriormente, se estudió el efecto del ácido asiático sobre la lesión hepática y renal inducida por lipopolisacáridos; sin embargo, el impacto del ácido asiático en las lesiones miocárdicas agudas inducidas por lipopolisacáridos continua sin estar completamente determinada. Sesenta pollos de engorde de un día de edad se dividieron aleatoriamente en los siguientes grupos experimentales: grupo control, grupo que recibió LPS solamente, grupo LPS + ácido asiático 15 mg/kg, grupo LPS + ácido asiático 30 mg/kg, grupo LPS + ácido asiático 60 mg/kg y control + ácido asiático 60 mg./kg grupo. La histopatología de los tejidos cardíacos se detectó mediante tinción con hematoxilina y eosina (H&E). Las expresiones de ARN mensajero y proteínas relacionadas con la dinámica mitocondrial y la mitofagia se detectaron mediante PCR cuantitativa en tiempo real, inmunotransferencia Western, inmunofluorescencia e inmunohistoquímica. Se encontraron células miocárdicas desorganizadas y fibras miocárdicas fracturadas en el grupo que recibió lipopolisacáridos, y se puede observar un evidente acúmulo de glóbulos rojos en los espacios entre las fibras miocárdicas en el grupo de dosis bajas de ácido asiático. Sin embargo, las dosis medias y altas de ácido asiático obviamente atenuaron estos cambios. Nuestros resultados mostraron que el ácido asiático restableció significativamente las expresiones de ARN mensajero y proteínas relacionadas con la dinámica mitocondrial mediante la promoción adicional de la mitofagia. Este estudio reveló el efecto del ácido asiático sobre las lesiones miocárdicas agudas inducidas por lipopolisacáridos en pollos de engorde. Basicamente, el ácido asiático reguló la homeostasis dinámica mitocondrial y promovió aún más la mitofagia. Estos nuevos hallazgos indican que el ácido asiático puede ser un fármaco potencial para mitigar lesiones miocárdicas agudas inducidas por lipopolisacáridos en pollos de engorde.

Polystyrene nanoplastics and cadmium co-exposure aggravated cardiomyocyte damage in mice by regulating PANoptosis pathway.

Micro/nanoplastics (M/NPs) are the novel contaminants ubiquitous in the environment. Cadmium (Cd), a kind of heavy metal pollutant widely distributed, could potentially co-exist with PS-NPs in the environment. However, their combined effects on cardiomyocyte and its molecular mechanism in mammals remained ambiguous. Here, we examined whether PANoptosis, an emerging and complicated kind of programmed cell death, was involved in PS-NPs and Cd co-exposure-elicited cardiac injury. In this study, 60 male mice were orally subjected to environmentally relevant concentrations of PS-NPs (1 mg/kg) and/or CdCl2 (1.5 mg/kg) for 35 days. As we speculated, PS-NPs and Cd co-exposure affected the expression of pyroptosis(Caspase-1, Cleaved-Caspase-1, GSDMD, N-GSDMD, AIM2, Pyrin, NLRP3, IL-18, IL-1ß)-, apoptosis(Caspase-3, Cleaved-Caspase-3, Caspase-8, Cleaved-Caspase-8, Caspase-7, BAX)- and necroptosis (t-RIPK3, p-RIPK3, t-RIPK1, p-RIPK1, t-MLKL, p-MLKL, ZBP1)-related genes and protein, resulting in growth restriction and damaged myocardial microstructure in mice. Notably, the combined effects on Cd and PS-NPs even predominantly aggravated the toxic damage. Intriguingly, we fortuitously discovered PS-NPs and/or Cd exposure facilitated linear ubiquitination of certain proteins in mice myocardium. In summation, this study shed light toward the effects of Cd and PS-NPs on cardiotoxicity, advanced the understanding of myocardial PANoptosis and provided a scientific foundation for further exploration of the combined toxicological effects of PS-NPs and heavy metals.

Lyciumbarbarum polysaccharides ameliorate canine acute liver injury by reducing oxidative stress, protecting mitochondrial function, and regulating metabolic pathways. / 枸杞多糖通过降低氧化应激、保护线粒体功能和调节代谢途径改善犬急性肝损伤.

The development of acute liver injury can result in liver cirrhosis, liver failure, and even liver cancer, yet there is currently no effective therapy for it. The purpose of this study was to investigate the protective effect and therapeutic mechanism of Lyciumbarbarum polysaccharides (LBPs) on acute liver injury induced by carbon tetrachloride (CCl4). To create a model of acute liver injury, experimental canines received an intraperitoneal injection of 1 mL/kg of CCl4 solution. The experimental canines in the therapy group were then fed LBPs (20 mg/kg). CCl4-induced liver structural damage, excessive fibrosis, and reduced mitochondrial density were all improved by LBPs, according to microstructure data. By suppressing Kelch-like epichlorohydrin (ECH)-associated protein 1 (Keap1), promoting the production of sequestosome 1 (SQSTM1)/p62, nuclear factor erythroid 2-related factor 2 (Nrf2), and phase II detoxification genes and proteins downstream of Nrf2, and restoring the activity of anti-oxidant enzymes like catalase (CAT), LBPs can restore and increase the antioxidant capacity of liver. To lessen mitochondrial damage, LBPs can also enhance mitochondrial respiration, raise tissue adenosine triphosphate (ATP) levels, and reactivate the respiratory chain complexes I‒V. According to serum metabolomics, the therapeutic impact of LBPs on acute liver damage is accomplished mostly by controlling the pathways to lipid metabolism. 9-Hydroxyoctadecadienoic acid (9-HODE), lysophosphatidylcholine (LysoPC/LPC), and phosphatidylethanolamine (PE) may be potential indicators of acute liver injury. This study confirmed that LBPs, an effective hepatoprotective drug, may cure acute liver injury by lowering oxidative stress, repairing mitochondrial damage, and regulating metabolic pathways.

Co-exposure to environmentally relevant concentrations of cadmium and polystyrene nanoplastics induced oxidative stress, ferroptosis and excessive mitophagy in mice kidney.

Nanoplastics (NPs) are defined as a group of emerging pollutants. However, the adverse effect of NPs and/or heavy metals on mammals is still largely unclear. Therefore, we performed a 35-day chronic toxicity experiment with mice to observe the impacts of exposure to Cadmium (Cd) and/or polystyrene nanoplastics (PSNPs). This study revealed that combined exposure to Cd and PSNPs added to the mice's growth toxicity and kidney damage. Moreover, Cd and PSNPs co-exposure obviously increased the MDA level and expressions of 4-HNE and 8-OHDG while decreasing the activity of antioxidase in kidneys via inhibiting the Nrf2 pathway and its downstream genes and proteins expression. More importantly, the results suggested for the first time that Cd and PSNPs co-exposure synergistically increased iron concentration in kidneys, and induced ferroptosis through regulating expression levels of SLC7A11, GPX4, PTGS2, HMGB1, FTH1 and FTL. Simultaneously, Cd and PSNPs co-exposure further increased the expression levels of Pink, Parkin, ATG5, Beclin1, and LC3 while significantly reducing the P62 expression level. In brief, this study found that combined exposure to Cd and PSNPs synergistically caused oxidative stress, ferroptosis and excessive mitophagy ultimately aggravating kidney damage in mice, which provided new insight into the combined toxic effect between heavy metals and PSNPs on mammals.

N-acetylcysteine combined with insulin attenuates myocardial injury in canines with type 1 diabetes mellitus by modulating TNF-α-mediated apoptotic pathways and affecting linear ubiquitination.

The exact pathogenesis of type 1 diabetes mellitus (DM) is still unclear. Numerous organs, including the heart, will suffer damage and malfunction as a result of long-term hyperglycemia. Currently, insulin therapy alone is still not the best treatment for type 1 DM. In order to properly treat and manage patients with type 1 DM, it is vital to seek a combination that includes both insulin and additional medications. This study aims to explore the therapeutic effect and mechanism of N-acetylcysteine (NAC) combined with insulin on type 1 DM. By giving beagle canines injections of streptozotocin (STZ) and alloxan (ALX) (20 mg/kg each), a model of type 1 DM was created. The results showed that this combination could effectively control blood sugar level, improve heart function, avoid the damage of mitochondria and myocardial cells, and prevent the excessive apoptosis of myocardial cells. Importantly, the combination can activate nuclear factor kappa-B (NF-κB) by promoting linear ubiquitination of receptor-interacting protein kinase 1 (RIPK1) and NF-κB-essential modulator (NEMO) and inhibitor of NF-κB (IκB) phosphorylation. The combination can increase the transcription and linear ubiquitination of Cellular FLICE (FADD-like IL-1ß-converting enzyme) -inhibitory protein (c-FLIP), diminish the production of cleaved-caspase-8 p18 and cleaved-caspase-3 to reduce apoptosis. This study confirmed that NAC combined with insulin can promote the linear ubiquitination of RIPK1, NEMO and c-FLIP and regulate the apoptosis pathway mediated by TNF-α to attenuate the myocardial injury caused by type 1 DM. Meanwhile, the research served as a resource when choosing a clinical strategy for DM cardiac complications.

Pesticide thiram exposure alters the gut microbial diversity of chickens.

Thiram is a major dithiocarbamate pesticide commonly found in polluted field crops, feed, and rivers. Environmental thiram exposure has been demonstrated to cause angiogenesis and osteogenesis disorders in chickens, but information regarding thiram influences on gut microbiota, apoptosis, and autophagy in chickens has been insufficient. Here, we explored the effect of thiram exposure on gut microbiota, apoptosis, and autophagy of chickens. Results demonstrated that thiram exposure impaired the morphology and structure of intestinal and liver tissues. Moreover, thiram exposure also triggered liver apoptosis and autophagy. The gut microbiota in chickens exposed to thiram exhibited a significant decline in alpha diversity, accompanied by significant shifts in taxonomic compositions. Bacterial taxonomic analysis indicated that thiram exposure causes a significant reduction in the levels of eight genera, as well as a significant increase in the levels of two phyla and 10 genera. Among decreased bacterial genera, seven genera even cannot be observed in the thiram-induced chickens. In summary, this study demonstrated that thiram exposure not only dramatically altered the gut microbial diversity and composition but also induced liver apoptosis and autophagy in chickens. Importantly, this study also conveyed a key message that the dysbiosis of gut microbiota may be one of the major pathways for thiram to exert its toxic effects.

Asiatic acid alleviates LPS-induced acute kidney injury in broilers by inhibiting oxidative stress and ferroptosis via activation of the Nrf2 pathway.

Asiatic acid (AA), a triterpenoid compound isolated from Centella asiatica, has anti-inflammatory, antioxidant and anticancer biological characteristics. To explore the effect of AA on LPS-induced acute kidney injury (AKI) in broilers, a total of 60 one-day-old broilers were randomly divided into 6 groups, including the normal group, AKI model group, AKI + AA 15 mg/kg group, AKI + AA 30 mg/kg group, AKI + AA 60 mg/kg group and normal + AA 60 mg/kg group. Hematoxylin-eosin staining was used to observe the histopathology in kidney tissue, and the mRNA and protein expressions related to oxidative stress and ferroptosis were tested by qPCR and western blotting respectively. AA mitigated vacuolar degeneration and enlarged glomerular space caused by LPS in kidney tissue. Additionally, AA significantly increased the mRNA levels of Nrf2, HO-1, NQO1, GCLC, GCLM, GPX4, SLC7A11 and FTH1, and decreased the mRNA levels of Keap1 and PTGS2 in LPS-induced AKI. Likewise, AA significantly upregulated the protein expressions of Nrf2, HO-1, NQO1, GPX4, SLC7A11 and FTH1, and downregulated the protein expressions of Keap1 and PTGS2 in LPS-induced AKI. These results suggested that AA alleviated LPS-induced AKI by inhibiting oxidative stress and ferroptosis through targeting regulation of the Nrf2 pathway in broilers.

Molecular Characteristics, Antigenicity, Pathogenicity, and Zoonotic Potential of a H3N2 Canine Influenza Virus Currently Circulating in South China.

Canine influenza viruses (CIVs) could be a source of influenza viruses which infect humans because canine are important companion pets. To assess the potential risk of H3N2 CIVs currently circulating in southern China to public health, biological characteristics of A/canine/Guangdong/DY1/2019 (CADY1/2019) were detected. CADY1/2019 bound to both avian-type and human-type receptors. CADY1/2019 had a similar pH value for HA protein fusion to human viruses, but its antigenicity was obviously different from those of current human H3N2 influenza viruses (IVs) or the vaccine strains recommended in the North hemisphere. CADY1/2019 effectively replicated in the respiratory tract and was transmitted by physical contact among guinea pigs. Compared to human H3N2 IV, CADY1/2019 exhibited higher replication in MDCK, A549, 3D4/21, ST, and PK15 cells. Sequence analysis indicated that CADY1/2019 is an avian-origin virus, and belongs to the novel clade and has acquired many adaptation mutations to infect other mammals, including human. Taken together, currently circulating H3N2 CIVs have a zoonotic potential, and there is a need for strengthening surveillance and monitoring of their pathogenicity.

Liver mitochondrial dysfunction and electron transport chain defect induced by high dietary copper in broilers.

Copper is an important trace mineral in the diet of poultry due to its biological activity. However, limited information is available concerning the effects of high copper on mitochondrial dysfunction. In this study, 72 broilers were used to investigate the effects of high dietary copper on liver mitochondrial dysfunction and electron transport chain defect. Birds were fed with different concentrations [11, 110, 220, and 330 mg of copper/kg dry matter (DM)] of copper from tribasic copper chloride (TBCC). The experiment lasted for 60 d. Liver tissues on d 60 were subjected to histopathological observation. Additionally, liver mitochondrial function was recorded on d 12, 36, and 60. Moreover, a site-specific defect in the electron transport chain in liver mitochondria was also identified by using various chemical inhibitors of mitochondrial respiration. The results showed different degrees of degeneration, mitochondrial swelling, and high-density electrons in hepatocytes. In addition, the respiratory control ratio (RCR) and oxidative phosphorylation rate (OPR) in liver mitochondria increased at first and then decreased in high-dose groups. Moreover, hydrogen peroxide (H2O2) generation velocity in treated groups was higher than that in control group, which were magnified by inhibiting electron transport at Complex IV. The results indicated that high dietary copper could decline liver mitochondrial function in broilers. The presence of a site-specific defect at Complex IV in liver mitochondria may be responsible for liver mitochondrial dysfunction caused by high dietary copper.

The Protective Roles of Selenium on Hepatic Tissue Ultrastructure and Mitochondrial Antioxidant Capacity in Copper-Overloaded Rats.

The aim of this study was to explore the effects of selenium addition on hepatic tissue ultrastructure and mitochondrial antioxidant capacity in copper-overloaded rats. Eighteen adult male Sprague-Dawley (SD) rats were randomly divided into three groups (n = 6 per group). Each group received 1 mL (intragastrically) of water (control, group I) or water containing copper chloride (CuCl2, 1 mol/L) (group II) or a mixture of CuCl2 (1 mol/L) with sodium selenite (Na2SeO3, 0.05 mol/L) (group III) once daily for 30 days. Histological examination revealed normal hepatocyte structure and no ultrastructural changes in mitochondria in controls. In contrast, group II exhibited severe ultrastructural alterations, fuzzy mitochondrial membranes, irregularly shaped and fragmented rough endoplasmic reticulum (RER), and the high melanin content; group III also exhibited larger amounts of engulfing vesicles (EV) in the cytoplasm. Compared to controls, the CuCl2 treatment lowered (P < 0.05) hepatocyte enzymatic activities and increased lipid peroxidation as indicated by an increase in malondialdehyde (MDA) levels. The effects of CuCl2 were attenuated by simultaneous administration with Na2SeO3. These results indicated that the adverse effects of copper toxicity can be partially attenuated by providing a source of selenium.

Protective role of selenium on aflatoxin b1-induced hepatic dysfunction and apoptosis of liver in ducklings.

Aflatoxin B1 (AFB1) is a mycotoxin which causes toxicity through oxidative damage. Selenium (Se), an antioxidative agent, can antagonize some toxicity induced by oxidative stress. The aim of this work was to investigate the toxicity of AFB1 and the protective effects of Se on duckling liver in vivo. The study consisted of three groups: AFB1, AFB1Tx, and a control group. AFB1 group was administered aflatoxin intragastrically (0.1 mg/kg body weight). AFB1Tx group was administered AFB1 intragastrically (0.1 mg/kg body weight) plus sodium selenite (1 mg/kg body weight). The control group was given the same volume of dimethyl sulfoxide (DMSO) via intragastric intubation. All three groups received daily administrations for 28 days. Blood samples were obtained on the 14th, 21st, and 28th days of post-administration, and the serum alanine aminotransferase (ALT) and aspartate transaminase (AST) were evaluated. A high level of serum ALT and AST was observed in AFB1 group. The activity of ALT and AST was significantly lower in Se treatment group than those in AFB1 group. Liver samples were collected on the 14th, 21st, and 28th days of post-administration, and concentrations of Bcl-2, Bax, caspase-3, and p53 were measured. Increased expression level of Bax, caspase-3, and p53 and decreased Bcl-2 expression level and Bcl-2/Bax ratio were observed in AFB1 group. Se diminished hepatic dysfunction, or damage and modulated the expression of apoptotic related proteins, in a time-dependent manner. In conclusion, concurrent treatment with Se reduced the AFB1-induced hepatic dysfunction and apoptosis.

Influence of selenium on hepatic mitochondrial antioxidant capacity in ducklings intoxicated with aflatoxin B1.

The aim of the study was to investigate the effect of selenium on hepatic mitochondrial antioxidant capacity in ducklings administrated with aflatoxin B(1) (AFB(1)). Ninety 7-day-old ducklings were randomly divided into three groups (groups I-III). Group I was used as a blank control. Group II was administered with AFB(1) (0.1 mg/kg body weight). Group III was administered with AFB(1) (0.1 mg/kg body weight) plus selenium (sodium selenite, 1 mg/kg body weight). All treatments were given once daily for 21 days. The results showed that the activities of mitochondrial superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione reductase (GR) in group II ducklings significantly decreased when compared with group I (P < 0.01). Furthermore, the content of hepatic mitochondrial malondialdehyde (MDA) significantly increased (P < 0.01). However, the activities of hepatic mitochondrial SOD, CAT, GSH-Px, and GR in group III ducklings significantly increased when compared with group II (P < 0.05). In addition, the content of hepatic mitochondrial MDA significantly decreased (P < 0.01). These results revealed that AFB(1) significantly induced hepatic mitochondrial antioxidant dysfunction. However, sodium selenite could significantly ameliorate the negative effect induced by AFB(1).

Influence of selenium on body weights and immune organ indexes in ducklings intoxicated with aflatoxin B1.

To investigate the influence of selenium on body weights and the immune organ indexes in ducklings administrated with aflatoxin B(1) (AFB(1)), 90 7-day-old ducklings were randomly divided into three groups (groups I-III). Group I was used as a blank control. Group II was administered with AFB(1) (0.1 mg/kg body weight). Group III was administered with AFB(1) (0.1 mg/kg body weight) plus sodium selenite (1 mg/kg body weight). All treatments were given once daily for 21 days. It showed that the ducklings' bursa of fabricius, thymus indexes, and body weights in group II significantly decreased when compared with group I (P < 0.01). Furthermore, the spleen indexes significantly decreased (P < 0.01). However, the ducklings' bursa of fabricius and thymus indexes, body weights in group III ducklings significantly increased when compared with group II (P < 0.01). In addition, the spleen indexes significantly decreased (P < 0.01). These results revealed that AFB(1) significantly affect ducklings' growth and immune organs development. However, selenium significantly ameliorated the negative effects induced by AFB(1).

Effect of copper chloride exposure on the membrane potential and cytosolic free calcium in primary cultured chicken hepatocytes.

This study was conducted to examine the effects of copper on membrane potential and cytosolic free calcium in isolated primary chicken hepatocytes which were exposed to different concentration of Cu(2+) (0, 10, 50, 100 µM) or a mixture of Cu(2+) and vitamin C (50 and 50 µM, respectively). Viability, membrane potential, and cytosolic free Ca(2+) of monolayer cultured hepatocytes were investigated at the indicated time point. Results showed that, among the different concentrations of Cu(2+) exposure, the viability of hepatocytes treated with 100 µM Cu(2+) was the worst at the 12th and 24th hours. The effects of Cu(2+) on viability and proliferation were time and dose dependent. Further investigation indicated that Cu(2+) exposure significantly enhanced cytosolic free Ca(2+) in hepatocytes, compared to that in control group, at the 24th hour. Meanwhile, membrane potential was noticeably reduced in hepatocytes increasing concentration of Cu(2+). Taking these results together, we have shown that Cu(2+) can cause toxicity to primary chicken hepatocytes in excessive dose and the effect of Cu(2+) exposure on membrane potential is not site specific, which is probably mediated by the changes of cytosolic free Ca(2+).

Protection of selenium on hepatic mitochondrial respiratory control ratio and respiratory chain complex activities in ducklings intoxicated with aflatoxin B1.

To investigate the protection of selenium on hepatic mitochondrial functions, 90 7-day-old ducklings were randomly divided into three groups (groups I-III). Group I was used as a blank control. Group II was administered with aflatoxin B(1) (0.1 mg/kg body weight). Group III was administered with aflatoxin B(1) (0.1 mg/kg body weight) plus selenium (sodium selenite, 1 mg/kg body weight). All treatments were given once daily for 21 days. The results showed that the activities of hepatic mitochondrial complexes I-IV in group II ducklings significantly decreased when compared with group I (P < 0.01). Furthermore, the activities of hepatic mitochondrial complexes I-IV in group III significantly increased when compared with group II (P < 0.05). The hepatic mitochondrial respiratory control ratio (RCR) in group II ducklings significantly decreased when compared with group I (P < 0.01). In addition, the hepatic mitochondrial RCR in group III significantly increased when compared with group II (P < 0.05). These results revealed that the aflatoxin B(1) significantly induced hepatic mitochondrial dysfunction in the activities of hepatic mitochondrial respiratory chain complexes I-IV and the RCR in ducklings. However, sodium selenite could significantly ameliorate the negative effect induced by aflatoxin B(1).

In vitro effect of copper chloride exposure on reactive oxygen species generation and respiratory chain complex activities of mitochondria isolated from broiler liver.

This study is to examine if Cu(2+) can act directly on mitochondria or indirectly by producing reactive oxygen species (ROS), isolated broiler hepatic mitochondria were exposed to different concentrations of Cu(2+) (10, 30, 50 µM). Respiratory chain complex activities, ROS generation, respiratory control ratio (RCR) and mitochondrial membrane potential were investigated. Dose-dependent inhibition of respiratory chain complexes and induction of ROS were observed, which coincided with decreasing RCR both with glutamate + malate or succinate. Further investigation indicated that the membrane potential determined by rhodamine 123 release decreased after CuCl(2) exposure at 30 and 50 µM. In addition, the effects of the antioxidants NAC (200 µM) and GSH (200 µM) were studied at 50 µM Cu(2+). The results indicate that Cu can induce mitochondrial dysfunction in excessive dose and the effect of Cu(2+) exposure on respiratory chain is not site-specific, and antioxidants can protect the mitochondrial function by reducing the formation of free radicals.

High copper levels promotes broiler hepatocyte mitochondrial permeability transition in vivo and in vitro.

This study was to examine the effects of copper on the mitochondrial non-specific pore. Three hundred sixty, one-day-old, healthy Arbor Acres (AA) broilers were fed with different concentrations (11, 110, 220, and 330 mg/kg) of copper originated from copper sulfate, tribasic copper chloride (TBCC), or copper methionine. At the indicated time point, the mitochondrial permeability transition (MPT) and copper concentration were analyzed. Results showed that under the same copper concentration, the MPT of broilers fed copper methionine was the greatest, followed by TBCC, then copper sulfate. The effects of copper on MPT were time- and dose-dependent. Furthermore, in vitro in the presence of K(+), 5 µM Cu(2+) could cause permeability transition as compared to 10 µM Cu(2+) in buffer without K(+). Taking these results together, we have shown that hepatocellular MPT may be influenced not only by source and concentration of copper or the raising period of broilers, but also by the existence of K(+).