Systematical analysis of impacts of heat stress on the proliferation, apoptosis and metabolism of mouse hepatocyte

Whole genome discovery of regulatory genes responsible for the response of chicken to heat stress

Long noncoding RNAs (lncRNAs) are functional bridges connecting the genome with phenotypes by interacting with DNA, mRNA, and proteins. Using publically available acute heat stress (AHS)-related RNA-seq data, we discovered novel lncRNAs and tested their association with AHS along with ~ 8800 known lncRNAs and ~ 28,000 mRNA transcripts. Our pipeline discovered a total of 145 potentially novel-lncRNAs. One of them (Fishcomb_p-value = 0.06) along with another novel transcript (annotated as protein-coding; Fishcomb_p-value = 0.03) were identified as significantly associated with AHS. We found five known-lncRNAs and 134 mRNAs transcripts that were significantly associated with AHS. Four novel lncRNAs interact cis-regulated with 12 mRNA transcripts and are targeted by 11 miRNAs. Also six meta-lncRNAs associate with 134 meta-mRNAs through trans-acting co-expression, each targeted by 15 and 216 miRNAs, respectively. Three of the known-lncRNAs significantly co-expressed with almost 97 of the significant mRNAs (Pearson correlation p-value < 0.05). We report the mentioned three known-lncRNAs (ENSGALT00000099876, ENSGALT00000107573, and ENSGALT00000106323) as the most, significantly regulatory elements of AHS in chicken. It can be concluded that in order to alleviate the adverse effects of AHS on chicken, the manipulation of the three regulatory lncRNAs could lead to a more desirable result than the manipulation of the most significant mRNAs.

Effects of Macleaya cordata Extract on Blood Biochemical Indices and Intestinal Flora in Heat-Stressed Mice

Heat stress (HS) leads to disturbance of homeostasis and gut microbiota. Macleaya cordata extract (MCE) has anti-inflammatory, antibacterial, and gut health maintenance properties. Still, the specific effects of MCE on blood biochemical indices and gut microbiota homeostasis in heat-stressed mice are not entirely understood. This study aimed to investigate the impact of MCE on blood biochemical indices and gut microbiota in heat-stressed mice. A control group (CON) (25 °C, n = 6) and HS group (42 °C, n = 6) were gavaged with normal saline 0.2 mL/g body weight/day, and HS plus MCE group (HS-MCE) (42 °C, n = 6) was gavaged with 5 mg MCE/kg/day. HS (2 h/d) on 8–14 d. The experiment lasted 14 days. The results showed that HS increased mice’ serum aspartate transaminase, alanine transferase activities, heat shock protein 70 level, and malondialdehyde concentrations, and decreased serum catalase and superoxide dismutase activities. HS also disrupted microbiota diversity and community structure in mice, increasing the Bacteroidetes and decreasing Firmicutes and Lactobacillus; however, MCE can alleviate the disturbance of biochemical indicators caused by HS and regulate the flora homeostasis. Furthermore, MCE was able to moderate HS-induced metabolic pathways changes in gut microbiota. The Spearman correlation analysis implied that changes in serum redox status potentially correlate with gut microbiota alterations in HS-treated mice.

Heat stress morbidity among US military personnel: Daily exposure and lagged response (1998-2019)

Heat stress illnesses represent a rising public health threat; however, associations between environmental heat and observed adverse health outcomes across populations and geographies remain insufficiently elucidated to evaluate risk and develop prevention strategies. In particular, military-relevant large-scale studies of daily heat stress morbidity responses among physically active, working-age adults to various indices of heat have been limited. We evaluated daily means, maximums, minimums, and early morning measures of temperature, heat index, and wet bulb globe temperature (WBGT) indices, assessing their association with 31,642 case-definition heat stroke and heat exhaustion encounters among active duty servicemembers diagnosed at 24 continental US installations from 1998 to 2019. We utilized anonymized encounter data consisting of hospitalizations, ambulatory (out-patient) visits, and reportable events to define heat stress illness cases and select the 24 installations with the highest case counts. We derived daily indices of heat from hourly-scale gridded climate data and applied a case-crossover study design incorporating distributed-lag, nonlinear models with 5 days of lag to estimate odds ratios at one-degree increments for each index of heat. All indices exhibited nonlinear odds ratios with short-term lag effects throughout observed temperature ranges. Responses were positive, monotonic, and exponential in nature, except for maximum daily WBGT, minimum daily temperature, temperature at 0600 h (local), and WBGT at 0600 h (local), which, while generally increasing, showed decreasing risk for the highest heat category days. The risk for a heat stress illness on a day with a maximum WBGT of 32.2 °C (90.0 °F) was 1.93 (95% CI, 1.82 - 2.05) times greater than on a day with a maximum WBGT of 28.6 °C (83.4 °F). The risk was 2.53 (2.36-2.71) times greater on days with a maximum heat index of 40.6 °C (105 °F) compared to 32.8 °C (91.0 °F). Our findings suggest that prevention efforts may benefit from including prior-day heat levels in risk assessments, from monitoring temperature and heat index in addition to WBGT, and by promoting control measures and awareness across all heat categories.

Comparison of the Effects of Intraperitoneal Injection with Carbon Tetrachloride on Acute Liver Toxicity in Male and Female Kunming Mice

Background

Acute chemical liver injury needs to be further explored. The present study aimed to compare the effects of intraperitoneal injection with carbon tetrachloride on acute liver toxicity after 24 h in male and female Kunming mice.

Material/Methods

In this study, female and male mice were simultaneously divided into 3 different groups. Each group was treated differently, and after 24 h, blood samples were collected to check for changes in the activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), which were used to assess liver toxicity. Liver samples were used for hematoxylin-eosin staining, and periodic acid Schiff reagent staining was performed to detect the pathological changes of each group. The expression level of biomarker molecules in liver cells was also systematically analyzed.

Results

Our results showed that, compared with male mice, female mice showed more serious damage: reduced glycogen and higher degree of necrosis, and the levels of heatshock protein 27 (HSP27), heat-shock protein 70 (HSP70), proliferating cell nuclear antigen (PCNA) and B cell lymphoma/lewkmia-2 (Bcl-2) were significantly lower than in the male group (P<0.05 or P<0.01), while the results of Bcl-2-associated X protein (Bax), cysteinyl aspartate specific proteinase 3 (Caspase3), and cytochrome P450 2E1 (CYP2E1) were the opposite (P<0.05 or P<0.01).

Conclusions

The findings from this study showed that, compared with male mice, at 24 h after CCl₄ toxicity, female mice showed more severe changes of hepatocyte necrosis and PAS-positivity, with significantly reduced expression of HSP27, HSP70, PCNA, and Bcl-2, and significantly increased expression of Bax, caspase-3, and CYP2E1.

Long-term exposure to p-Nitrophenol induces hepatotoxicity via accelerating apoptosis and glycogen accumulation in male Japanese quails

p-Nitrophenol (PNP) is the main end product of organophosphorus insecticides and a derivative of diesel exhaust particles. In addition to its unfavorable impact on reproductive functions in both genders, it also has various harmful physiological effects including lung cancer and allergic rhinitis. The identification of the cellular readout that functions in metabolic pathway perpetuation is still far from clear. This research aimed to study the impact of chronic PNP exposure on the health condition of the liver in Japanese quails. Quails were exposed to different concentrations of PNP as follows: 0.0 (control), 0.01mg (PNP/0.01), 0.1mg (PNP/0.1), and 1mg (PNP/1) per kg of body weight for 2.5 months through oral administration. Liver and plasma samples were collected at 1.5, 2, and 2.5 months post-treatment for biochemical, histopathology, and immunohistochemistry assessment. The plasma aspartate aminotransferase (AST) level was assessed enzymatically. The livers were collected for histopathology, glycogen accumulation, proliferating cell nuclear antigen (PCNA), and apoptosis assessment. Our results revealed an irregularity in body weight due to the long-term exposure of PNP with a significant reduction in liver weight. PNP treatment caused histopathological alterations in the hepatic tissues which increased in severity by the long-term exposure. The low dose led to mild degeneration with lymphocytic infiltration, while the moderate dose has a congestion effect with some necrosis; meanwhile severe hepatocyte degeneration and RBCs hemolysis were noticed due to high dose of PNP. Glycogen accumulation increased in hepatocytes by prolonged exposure to p-Nitrophenol with the highest intensity in the group treated by the high dose. Moderate and high doses of PNP resulted in a significant increase in apoptosis and hepatocytes' proliferation at the different time points after treatment. This increase is markedly notable and maximized at 2.5 months post-treatment. The damage occurred in a time-dependent manner. These changes reflected on the plasma hepatic enzyme AST that was clearly increased at 2.5 months of exposure. Therefore, it could be concluded that PNP has profound toxic effects on the liver in cellular level. Taking into consideration the time and dose factors, both have a synergistic effect on the accumulation of glycogen, apoptosis, and cellular proliferation, highlighting the power of cellular investigation which will potentially open the door for earlier medical intervention to counteract this toxicity. Collectively, PNP could have critical hurtful effects on the health of human beings, wild animals as well as livestock.

Hepatic lipid metabolomics in response to heat stress in local broiler chickens breed (Huaixiang chickens)

High-temperature environment-induced heat stress (HS) is a hazard environmental element for animals, leading to dramatic changes in physiological and metabolic function. However, the metabolomic-level mechanisms underlying lipid metabolism in liver of slow-growing broilers are still obscure. The present study investigated the effects of HS on hepatic lipidomics in Chinese indigenous slow-growing broilers (Huaixiang chickens). The study includes two treatments, each treatment had 5 replicates with 4 broilers per cage, where a total of 40 eight-week-old female Huaixiang chickens (average initial body weight of 840.75 ± 20.79 g) were randomly divided into normal temperature (NT) and HS groups for 4 weeks, and the broilers of NT and HS groups were exposed to 21.3 ± 1.2℃ and 32.5 ± 1.4℃ respectively. The relative humidity of the two groups was maintained at 55%-70%. The liquid chromatography-mass spectrometry (LC-MS)-based metabolomics were conducted to evaluate the changes in hepatic lipidomics of broilers. The results showed that there were 12 differential metabolites between the two treatments. Compared with the NT group, HS group reduced the levers of hepatic phosphatidylcholine (PC) (16:0/16:0), PC (16:0/18:2), triglyceride (TG) (16:0/16:1/18:1), TG (18:0/18:1/20:4) (VIP > 1 and p < 0.05), while increased PC (18:1/20:3), PC (18:0/18:1), PC (18:1/18:1), PC (18:0/22:5), dimethyl-phosphatidyl ethanolamine (dMePE) (14:0/18:3), dMePE (18:0/18:1) and dMePE (16:0/20:3) levels (Variable Importance in the Projection; VIP > 1 and p < 0.05). In addition, according to the analysis of metabolic pathway, the pathways of linoleic acid, alpha-linolenic acid, glycerolipid and glycerophospholipid metabolism were involved in the effects of HS on hepatic lipid metabolism of broilers (p < 0.05). In conclusion, HS altered the hepatic lipid metabolism mainly through linoleic acid, alpha-linolenic acid, glycerolipid and glycerophospholipid metabolism pathway in indigenous broilers. These findings provided novel insights into the role of HS on hepatic lipidomics in Chinese indigenous broiler chickens.

Lactobacillus plantarum FRT10 alleviated high-fat diet-induced obesity in mice through regulating the PPARα signal pathway and gut microbiota

Previous studies showed that probiotics supplementation contributed to alleviate obesity. This work was to assess the efficacy of Lactobacillus plantarum FRT10 from sour dough in alleviating obesity in mice fed with a high-fat diet (HFD), and the underlying mechanisms focusing on modulation of the gut microbiota profile. Kunming mice were fed with a regular diet (CT), a high-fat diet (HFD), and two HFDs containing low and high doses of L. plantarum FRT10 for 8 weeks. The physiological and biochemical modulations in liver were analyzed. Cecal contents were analyzed by high-throughput 16S ribosomal RNA sequencing. FRT10 supplementation significantly reduced body weight gain, fat weight, and liver triacylglycerols (TGs) and alanine aminotransferase (ALT) concentrations (P < 0.05). FRT10 significantly ameliorated the HFD-induced gut dysbiosis, as evidenced by increased abundance of microbes, including Butyricicoccus, Butyricimonas, Intestinimonas, Odoribacter, and Alistipes, and decreased abundance of Desulfovibrionaceae, Roseburia, and Lachnoclostridium. Lactobacillus, Bifidobacterium, and Akkermansia were markedly increased after FRT10 intervention. In addition, real-time quantitative PCR revealed that FRT10 upregulated the mRNA expression levels of peroxisome proliferator-activated receptor-α (PPARα) and carnitine palmitoyltransferase-1α (CPT1α), and downregulated the mRNA expression levels of sterol regulatory element-binding protein 1 (SREBP-1) and TG-synthesizing enzyme diacylglycerol acyltransferase 1 (DGAT1) in liver. These findings suggested that FRT10 had anti-obesity effects in obese mice partly related to the activation of PPARα/CPT1α pathway. FRT10 can be considered a single probiotic agent for preventing HFD-induced obesity in humans and animals.

Comparative study of the proliferative ability of skeletal muscle satellite cells under microwave irradiation in fractures with titanium alloy internal fixation in rabbits

The aim of the present study was to investigate the proliferation of skeletal muscle satellite cells (MSCs) under different amounts of microwave irradiation in fractures with titanium alloy internal fixation. A total of 45 male New Zealand adult white rabbits were used to establish a femoral shaft fracture and titanium alloy internal fixation model. The rabbits were randomly divided into the control group (group A) and the experimental groups (groups B and C). For 15 days, groups B and C were exposed to microwave treatment (25 or 50 W, respectively) for 10 min per day. The quadriceps femoris muscle was used for the isolation and culture of MSCs in vitro. The cultured cells were identified using cellular immunohistochemical staining. Transmission electron microscopy was used to observe mitochondrial ultrastructure damage, MTT assays were used to detect cell viability and cell cycle phases were analyzed by flow cytometry. The results revealed that, following 48 or 72 h of culture, cell viability was significantly greater in group B compared with group A, and was significantly lower in group C compared with group A (P<0.05). Compared with group A, the percentage of the cell population in the G0/G1 phase in group B was significantly decreased (P<0.05) and the proportion in the S and G2/M phases was increased (P<0.05). These results were reversed in group C; the percentage of cells in the S and G2/M phases was significantly lower (P<0.05) and in the G0/G1 phase was significantly higher (P<0.05) than in group A. These results suggested that in the healing of fractures with titanium, the proliferation of MSCs is significantly affected by microwave radiation in a dose-dependent manner.

In Utero Heat Stress Alters the Offspring Epigenome

Exposure to intrauterine heat stress during late gestation affects offspring performance into adulthood. However, underlying mechanistic links between thermal insult in fetal life and postnatal outcomes are not completely understood. We examined morphology, DNA methylation, and gene expression of liver and mammary gland for bull calves and heifers that were gestated under maternal conditions of heat stress or cooling (i.e. in utero heat stressed vs. in utero cooled calves). Mammary tissue was harvested from dairy heifers during their first lactation and liver from bull calves at birth. The liver of in utero heat stressed bull calves contained more cells and the mammary glands of in utero heat stressed heifers were comprised of smaller alveoli. We identified more than 1,500 CpG sites differently methylated between maternal treatment groups. These CpGs were associated with approximately 400 genes, which play a role in processes, such as development, innate immune defense, cell signaling, and transcription and translation. We also identified over 100 differentially expressed genes in the mammary gland with similar functions. Interestingly, fifty differentially methylated genes were shared by both bull calf liver and heifer mammary gland. Intrauterine heat stress alters the methylation profile of liver and mammary DNA and programs their morphology in postnatal life, which may contribute to the poorer performance of in utero heat stressed calves.

Molecular mechanism for the influence of gender dimorphism on alcoholic liver injury in mice

It is known that women develop alcoholic liver injury more rapidly and have a lower alcohol toxic threshold than men. However, the detailed molecular mechanisms remain unclear. The precise mechanism responsible for the sex difference needs to be determined. Female and male mice were given ethanol by intragastric infusion every day for 4 weeks. The pathological changes were detected by hematoxylin-eosin, Sirius red, oil red O, periodic acid-Schiff, and Hochest33258 staining in the liver of female and male mice. The related gene and protein expression of hepatocytes stress, proliferation and apoptosis, glycogen synthesis, lipid metabolism, and hepatic fibrosis were also systematically analyzed in the female and male mice. Livers from ethanol-treated female mice had more serious hepatocyte necrosis, liver fibrosis ( P < 0.01), substantial micro/macrovesicular steatosis ( p < 0.01), glycogen consumption ( p < 0.05), and hepatocytes apoptosis ( p < 0.05) than ethanol-treated male mice. The expression of heat shock protein 27 (HSP27), HSP70, proliferating cell nuclear antigen, B-cell lymphoma/leukemia-2 (Bcl-2), and phosphorylated signal transducer and activators of transcription 3 (p-STAT3) was higher in ethanol-treated male mice than ethanol-treated female mice ( P < 0.05 or P < 0.01). But, the expression of Bax (Bcl-2-associated X protein), Caspase 3, CYP2E1 (cytochrome P4502E1), and transforming growth factor βl had the contrary results. Our study suggested that ethanol treatment induced more expression of HSP27 and HSP70, faster hepatocyte proliferation, higher level of glycogen, and interleukin-6 signaling pathway activation, but less hepatocyte apoptosis and CYP2E1 expression in male mice than female mice, which could be helpful to understand the molecular mechanism for the influence of sex difference on alcoholic liver injury.

Effects of paeoniflorin on neurobehavior, oxidative stress, brain insulin signaling, and synaptic alterations in intracerebroventricular streptozotocin-induced cognitive impairment in mice

Paeoniflorin (PF) is a natural monoterpene glycoside in Paeonia lactiflora pall with anti-diabetic, antioxidant, anti-inflammatory, and neuro-protective properties. This study was designed to investigate the neuroprotective effects of PF against cognitive deficits induced by intracerebroventricular (ICV) injection of streptozotocin (STZ) in mice. STZ was injected twice intracerebroventrically (3 mg/kg ICV) on alternate days (day 1 and day 3) in mice. Daily treatment with PF (10 mg/kg per day, intraperitoneally) starting from the first dose of STZ for 21 days showed an improvement in ICV-STZ induced cognitive deficits as assessed by novel object recognition and Morris water maze (MWM) test. PF significantly attenuated STZ induced mitochondrial dysfunction manifested by dramatically elevated cytochrome c oxidase activity and ATP synthesis, and restoration of the mitochondrial membrane potential (MMP), and oxidative stress in hippocampus and in the cortex compared to control. Moreover, PF treatment also markedly increased synaptic density in the CA1 region of the hippocampus compared to control. Furthermore, PF ameliorated defective insulin signaling by up-regulating p-PI3K and p-Akt protein expression while downregulating p-IRS-1 protein expression. Taken together, the outcomes of the current study suggest the therapeutic potential of PF in the cognitive deficits induced by ICV-STZ.

Short-term treadmill exercise in a cold environment does not induce adrenal Hsp72 and Hsp25 expression

Heat shock proteins (Hsps) have a critical role in maintaining cellular homeostasis and in protecting cells from a range of acute and chronic stressful conditions. Treadmill running exercise results in increased Hsp72 and Hsp25 levels in various tissues and heat production during exercise has been shown to be the main factor for the increased levels of Hsp72 in myocardium. Since the adrenal gland plays a vital role in general response to stress, regulation of Hsps in adrenal glands following stressful events seems to be critical for controlling the whole-body stress response appropriately. This study tested the hypothesis of whether elevation of temperature is solely responsible for exercise-induced adrenal Hsp72 and Hsp25 expression. Female Sprague-Dawley rats (3 months old) were randomly assigned to either a sedentary control group or one of two treadmill-running groups: a cold exercise group run in a cold room at 4 °C (CE), and a warm exercise group run at 25 °C temperature (WE). Animals were run 60 min a day at 30 m min-1 speed for 4 consecutive days following adaptation to treadmill exercise. Exercise resulted in a significant elevation of body temperature only in the WE group (p < 0.05). Adrenal Hsp72 and Hsp25 levels were significantly higher in the WE group compare to the other groups (p < 0.05). These data demonstrated that exercise-related elevations of body temperature could be the only factor for the inductions of adrenal Hsp72 and Hsp25 expression.

Heat stress inhibits proliferation, promotes growth, and induces apoptosis in cultured Lantang swine skeletal muscle satellite cells

Proliferation suppression and apoptosis are the prominent characteristics induced by heat stress (HS) in cells, whereas the effects of HS on cell growth (mass accumulation) are unknown. In this study, Lantang swine (an indigenous breed of China) skeletal muscle satellite cells (SCs) were pre-cultured at 37 °C for 24 h. The HS group was subjected to HS at 41 °C, while the control group was maintained at 37 °C. Heat shock protein 70 (HSP70) expression and SC size are significantly increased (P<0.05) by HS, but cell proliferation is suppressed (P<0.05) and apoptosis is induced (P<0.05). HS led to a lower percentage of SCs in the G0/G1 phase (P<0.05) together with a higher percentage of SCs in the S phase (P<0.05). However, the percentage of SCs in the G2/M phase was decreased (P<0.05) at 48 h but then increased (P<0.05) at 72 h with HS. In addition, the phosphorylation ratios of protein kinase b (Akt), ribosomal protein S6 kinase (S6K), and ribosomal protein S6 were increased (P<0.05) by HS. Nevertheless, the phosphorylation ratios of the 4E binding protein 1 and the eukaryotic initiation factor-4E were indistinguishable (P>0.05) from those of the control group. The phosphorylation ratio of the mammalian target of rapamycin (mTOR) (Ser(2448)) increased (P<0.05) within 48 h, and apparent differences were abrogated at 72 h (P>0.05). Moreover, cleaved caspase-3 expression was increased at 72 h (P<0.05). These findings indicate that HS induces apoptosis and disrupts cell cycle distribution to decrease the number of cells. Additionally, HS can promote SC growth via an activated Akt/mTOR/S6K signaling pathway.

Changes of collagen fibers in development of alcoholic liver injury

AIM: To observe the change of collagen fibers in the development of alcohol induced liver injury in mice, and investigate the relationship between the change of collage fibers and the stage of alcoholic liver injury.

METHODS: Forty BALB/c mice were randomly divided into two groups: a normal group (n = 3) and a model group (n = 37). Mice of the normal group were sacrificed after adapting the environment for one week, and all the mice of the model group were given 0.15 mL/10 kg Red Star Erguotou (56 degrees) daily by gavage for 4 weeks. Each three mice were sacrificed at 1, 2, 3, and 4 weeks after alcohol administration (n = 37). Sirius red staining was used to observe collagen fibers in the liver tissue. Western blot was used to detect liver proliferation cell nuclear antigen (PCNA) protein expression. Image-ProPlus6.0 software was used to analyze the integral optical density (IOD) of the samples, and the gray levels of target protein bands were measured with Gel Pro4.0 software. ANOVE and nonparametric rank sum test were used to analyze the significance of the data.

RESULTS: The contents of collagen fibers increased significantly at 1 and 2 weeks (852.21 ± 10.65 vs 345.24 ± 65.94, 1054.15 ± 10.80 vs 852.21 ± 10.65, P < 0.01), peaked at 2 weeks, and then decreased at 3 and 4 weeks (588.75 ± 17.18 vs 1054.15 ± 0.80, 559.40 ± 14.17, P < 0.01). The content of PCNA protein in the liver tissue of mice decreased significantly in the first two weeks, reached the minimum value at 2 weeks, and then increased at 3 and 4 weeks (P < 0.05).

CONCLUSION: In the process of alcohol induced liver injury in mice, the content of collagen fibers in the liver increases first and then decreases, and the expression of PCNA shows significant dynamic changes. The changes may be closely related to the mechanism of liver injury.

Establishment of a new animal model of azithromycin-induced liver injury and study the molecular pathological change during the process

The purpose of the present study is to establish a new animal model of azithromycin (AZ)-induced liver injury and study the molecular pathological change during the process. First, mice were respectively injected intraperitoneally with AZ of different high doses. Our results showed that 800 mg/kg AZ injection significantly induced liver injury in the mice, which reflected an ideal process of liver injury and repair. In this study, we analyzed the molecular pathological changes during the process by hematoxylin and eosin staining, immunohistochemistry, Western blot, and quantitative real-time reverse transcription polymerase chain reaction in the liver of mice at 0, 12, 24, 48, and 72 h after 800 mg/kg injection. Our results showed that the expression of heat shock protein 70, proliferating cell nuclear antigen, vascular endothelial growth factor, caspase 3, and cytochrome P450 2E1 were significantly differently expressed during liver injury induced by 800 mg/kg AZ in mice. Our results will be conducive for further study of the pathogenesis and prevention of drug-induced liver injury.

IL-6 trans-signaling plays important protective roles in acute liver injury induced by acetaminophen in mice

Our study was undertaken to evaluate the important role of interleukin-6 (IL-6) trans-signaling in acetaminophen (AAP)-induced liver injury. A soluble gp130 protein (sgp130Fc) exclusively inhibits IL-6 trans-signaling, whereas an IL-6/soluble IL-6 receptor (sIL-6R) fusion protein (hyper-IL-6) mimics IL-6 trans-signaling. Using these tools, we investigated the role of IL-6 trans-signaling in AAP-induced liver injury. Blockade of IL-6 trans-signaling during AAP-induced liver injury remarkably increased the levels of serum aspartate aminotransferase and alanine aminotransferase; lowered the level of serum sIL-6R; aggravated liver injury; inhibited the expression of phosphorylation of STAT3 (pSTAT3), proliferating cell nuclear antigen, vascular endothelial growth factor, and glycogen synthesis; and induced the expression of Caspase3, cytochrome P450 2E1 (CYP2E1), and hepatocyte apoptosis in the liver of mice. In summary, our study suggested that IL-6 trans-signaling plays important protective roles by regulating the hepatocyte proliferation and apoptosis, angiogenesis, CYP2E1 expression, and glycogen metabolism during AAP-induced liver injury in mice.

The important role of ADAM8 in the progression of hepatocellular carcinoma induced by diethylnitrosamine in mice

This study focuses on investigating the concrete role of a disintegrin and metalloproteinase 8 (ADAM8) in the progression of hepatocellular carcinoma (HCC). Mice received anti-ADAM8 monoclonal antibody (mAb) of 100 μg/100 μl, 200 μg/100 μl or 300 μg/100 μl, respectively, in phosphate-buffered saline (PBS) or PBS intervention during the progression of HCC induced by diethylnitrosamine. The survival rate, body weight, and relative liver weight were determined in the mice. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and α-fetoprotein (AFP) level, hematoxylin–eosin staining, the expression level of vascular endothelial growth factor A (VEGF-A), proliferating cell nuclear antigen (PCNA), caspase 3 (Casp3), B cell leukemia 2 (Bcl2), B cell leukemia 2-associated X protein (Bax), protein p53 (P53), and ADAM8 were detected in the mice at the end of the 24th week. Our results showed that anti-ADAM8 mAb intervention effectively improved the survival rate, reduced the body weight loss and increased the relative liver weight in mice in a dose-dependent manner ( p < 0.05 or p < 0.01). Anti-ADAM8 mAb intervention also significantly lowered serum AST, ALT, and AFP levels ( p < 0.05 or p < 0.01), slowed the progression of HCC ( p < 0.05 or p < 0.01), induced the expression of Casp3, Bax, and P53 ( p < 0.05 or p < 0.01), and inhibited the expression of VEGF-A, PCNA, and Bcl2 in the liver of mice ( p < 0.05 or p < 0.01) in a dose-dependent manner compared with the mice receiving PBS intervention. Our study suggested that ADAM8 might promote the progression of HCC by regulating the expression of these factors. Anti-ADAM8 mAb intervention might be suitable as a potential method for HCC therapy.

Fluorescence based cell counting in collagen monolayer cultures of primary hepatocytes

Accurate determination of cell number is essential for the quantitative description of biological processes. The changes should be related to a measurable reference e.g. in the case of cell culture, the viable cell number is a very valuable reference parameter. Indirect methods of cell number/viability measurements may have up to 10 % standard deviation. This can lead to undesirable large deviations in the analysis of "-omics" data as well as time course studies. Such data should be preferably normalized to the exact viable cell number at a given time to allow meaningful interpretation and understanding of the biological processes. Manual counting of cell number is very laborious and not possible in certain experimental setups. We therefore, developed a simple and reliable fluorescence based method with an accuracy of 95-98 % for the determination of the viable cell number in situ. We optimized the seeding cell densities for primary rat hepatocytes for optimal cell adhesion. This will help in efficient use of primary cells which are usually limited in availability. The method will be very useful in the application of "-omics" techniques, especially metabolome analysis where the specific rates of uptake/production of metabolites can be reliably calculated.

Beneficial effects of dietary probiotics mixture on hemato-immunology and cell apoptosis of Labeo rohita fingerlings reared at higher water temperatures

Probiotics play an important role in growth increment, immune enhancement and stress mitigation in fish. Increasing temperature is a major concern in present aquaculture practices as it markedly deteriorates the health condition and reduces the growth in fish. In order to explore the possibilities of using probiotics as a counter measure for temperature associated problems, a 30 days feeding trial was conducted to study the hemato-immunological and apoptosis response of Labeo rohita (8.3±0.4 g) reared at different water temperatures, fed with or without dietary supplementation of a probiotic mixture (PM) consisting of Bacillus subtilis, Lactococcus lactis and Saccharomyces cerevisiae) (10¹¹ cfu kg⁻¹). Three hundred and sixty fish were randomly distributed into eight treatment groups in triplicates, namely, T1(28°C+BF(Basal feed)+PM), T2(31°C+BF+PM), T3(34°C+BF+PM), T4(37°C+BF+PM), T5(28°C+BF), T6(31°C+BF), T7(34°C+BF) and T8(37°C+BF). A significant increase (P<0.01) in weight gain percentage was observed in the probiotic fed fish even when reared at higher water temperature (34–37°C). Respiratory burst assay, blood glucose, erythrocyte count, total serum protein, albumin, alkaline phosphatase and acid phosphatase were significantly higher (P<0.01) in the probiotic fed groups compared to the non-probiotic fed groups. A significant (P<0.01) effect of rearing temperature and dietary probiotic mixture on serum myeloperoxidase activity, HSP70 level and immunoglobulin production was observed. Degree of apoptosis in different tissues was also significantly reduced in probiotic-supplemented groups. Hence, the present results show that a dietary PM could be beneficial in enhancing the immune status of the fish and also help in combating the stress caused to the organism by higher rearing water temperature.

Proper heat shock pretreatment reduces acute liver injury induced by carbon tetrachloride and accelerates liver repair in mice

Whether proper heat shock preconditioning can reduce liver injury and accelerate liver repair after acute liver injury is worth study. So mice received heat shock preconditioning at 40°C for 10 minutes (min), 20 min or 30 min and recovered at room temperature for 8 hours (h) under normal feeding conditions. Then acute liver injury was induced in the heat shock-pretreated mice and unheated control mice by intraperitoneal (i.p.) injection of carbon tetrachloride (CCl₄). Hematoxylin and eosin (H&E) staining, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and the expression levels of heat shock protein 70 (HSP70), cytochrome P450 1A2 (CYP1A2) and proliferating cell nuclear antigen (PCNA) were detected in the unheated control mice and heat shock-pretreated mice after CCl₄ administration. Our results showed that heat shock preconditioning at 40°C for 20 min remarkably improved the mice’s survival rate (P<0.05), lowered the levels of serum AST and ALT (P<0.05), induced HSP70 (P<0.01), CYP1A2 (P<0.01) and PCNA (P<0.05) expression, effectively reduced liver injury (P<0.05) and accelerated the liver repair (P<0.05) compared with heat shock preconditioning at 40°C for 10 min or 30 min in the mice after acute liver injury induced by CCl₄ when compared with the control mice. Our results may be helpful in further investigation of heat shock pretreatment as a potential clinical approach to target liver injury

Assessing the short-term effects of heatwaves on mortality and morbidity in Brisbane, Australia: comparison of case-crossover and time series analyses

Background

Heat-related impacts may have greater public health implications as climate change continues. It is important to appropriately characterize the relationship between heatwave and health outcomes. However, it is unclear whether a case-crossover design can be effectively used to assess the event- or episode-related health effects. This study examined the association between exposure to heatwaves and mortality and emergency hospital admissions (EHAs) from non-external causes in Brisbane, Australia, using both case-crossover and time series analyses approaches.

Methods

Poisson generalised additive model (GAM) and time-stratified case-crossover analyses were used to assess the short-term impact of heatwaves on mortality and EHAs. Heatwaves exhibited a significant impact on mortality and EHAs after adjusting for air pollution, day of the week, and season.

Results

For time-stratified case-crossover analysis, odds ratios of mortality and EHAs during heatwaves were 1.62 (95% confidence interval (CI): 1.36–1.94) and 1.22 (95% CI: 1.14–1.30) at lag 1, respectively. Time series GAM models gave similar results. Relative risks of mortality and EHAs ranged from 1.72 (95% CI: 1.40–2.11) to 1.81 (95% CI: 1.56–2.10) and from 1.14 (95% CI: 1.06–1.23) to 1.28 (95% CI: 1.21–1.36) at lag 1, respectively. The risk estimates gradually attenuated after the lag of one day for both case-crossover and time series analyses.

Conclusions

The risk estimates from both case-crossover and time series models were consistent and comparable. This finding may have implications for future research on the assessment of event- or episode-related (e.g., heatwave) health effects.