Nuclear changes in the cytotoxic T lymphocyte-induced model of apoptosis

Toxic effect of alpha cypermethrin, an environmental pollutant, on myocardial tissue in male wistar rats

α-Cypermethrin (CYP) is a pyrethroid insecticide-like environmental pollutant, widely found in the environment. New research links exposure to high levels of CYP to health damage; however, little is known about the effect of CYP on cardiovascular disease. The purpose of the present study was to evaluate, for the first time, biochemical and cardiovascular changes in male rats resulting from subchronic CYP exposure. The animals were divided into three groups: group 1 served as the control, group 2 (CYP1) received 4 mg/kg of CYP by gavage, and group 3 (CYP2) received 8 mg/kg of CYP by gavage, for 8 weeks each. Results showed that both CYP1 and CYP2 markedly increased plasma concentrations of cardiac markers (LDH, CK-MB, and troponin-T). Moreover, compared to the control group, CYP treatment elevated cardiac oxidative stress, as shown by increased MDA level and decreased activity of SOD, CAT, and GSH-Px. In addition, CYP2 caused a significant increase of 42% the concentration of total cholesterol and more than 75% in triglycerides compared to the control group. Furthermore, DNA fragmentation and collagen deposition were both amplified owing to CYP toxicity. This harmful effect was confirmed by a histological study using H-E and Sirius Red staining. Overall, our results clearly proved the cardiotoxicity caused by α-cypermethrin.

Hepatoprotective activity of raspberry ketone is mediated via inhibition of the NF-κB/TNF-α/caspase axis and mitochondrial apoptosis in chemically induced acute liver injury

Raspberry Ketone (RK) is a natural phenolic compound which is marketed nowadays as a popular weight-reducing remedy, with reported antioxidant and anti-inflammatory activities. However, its biological activity is not fully elucidated. Hepatotoxicity is the leading cause of acute liver failure in Europe and North America, and its management is still challenging. Therefore, this study aimed to assess the therapeutic detoxification activity of RK against liver injury in vivo and to explore the underlying mechanisms using carbon tetrachloride (CCl4)-induced hepatotoxicity as a model. First, a dose-response study using 4 different doses, 25, 50, 100, and 200 mg kg-1 day-1, of RK was conducted. RK was administered for 5 days as a pretreatment, followed by a single dose of CCl4 (1 ml kg-1, 1 : 1 v/v CCl4 : olive oil). The RK dose of 200 mg kg-1 showed the greatest protective effect and was selected for further investigations. CCl4 hepatotoxicity was confirmed by elevation of liver enzymes, and histopathological examination. CCl4-induced oxidative stress was evident from increased lipid peroxidation measured as thiobarbituric acid reactive substances (TBARS) along with depleted superoxide dismutase (SOD), reduced glutathione (GSH), and total antioxidant capacity (TAC). Increased oxidative stress was associated with increased cytochrome c expression with subsequent activation of caspase-9 and caspase-3, in addition to DNA fragmentation reflecting apoptosis. CCl4 also induced the expression of inflammatory cytokines (NF-κB and TNF-α). Interestingly, RK hepatoprotective activity was evident from the reduction of liver enzymes, and maintenance of hepatocyte integrity and microstructures as evaluated by histopathological examination using H and E, and transmission electron microscopy. The antioxidant activity of RK was demonstrated by the increase of TAC, SOD, and GSH, with a concomitant decrease of the TBARS level. Moreover, RK pretreatment inhibited CCl4-induced upregulation of inflammatory mediators. RK antiapoptotic activity was indicated by the reduction of the expression of cytoplasmic cytochrome-C, a decrease of caspases, and inhibition of DNA fragmentation. In conclusion, this study demonstrates that RK is a promising hepatoprotective agent. The underlying mechanisms include antioxidant, anti-inflammatory, and anti-apoptotic activities. This is the first study reporting RK hepatoprotective activity in acute hepatic injury and approves its antiapoptotic effect in the liver.

Cardiotoxicity and myocardial infarction-associated DNA damage induced by thiamethoxam in vitro and in vivo: Protective role of Trigonella foenum-graecum seed-derived polysaccharide

The risk of pesticides on the human health and environment has drawn increasing attention. Today, new tools are developed to reduce pesticide adverse effects. This study aimed to evaluate the toxicity induced by, thiamethoxam (TMX), and the cytoprotective effect of a novel polysaccharide, named fenugreek seed water polysaccharide (FWEP) in vitro using H9c2 cardiomyoblastes and in vivo using Wistar rat model. Animals were assigned into four groups per eight rats each: group 1 served as a control group, group 2 received TMX, group 3, and group 4 received both FWEP and TMX tested at two doses (100 and 200 mg/kg, respectively). Regarding the in vitro study, our results demonstrated that TMX induced a decrease in H9c2 cell viability up to 70% with the highest concentration. In vivo, TMX injection induced marked heart damage noted by a significant increase in plasma lactate dehydrogenase, creatine phosphokinase, troponin-T, aspartate amino transferase activities, cholesterol, and triglyceride levels. Concomitant alterations in cardiac antioxidant defense system revealed depletion in the levels of glutathione and non-protein thiol and an increase in the activity of superoxide dismutase, catalase, and glutathione peroxidase. Similarly, a significant increase in heart lipid, malondialdehyde, advanced oxidation protein product and in protein carbonyls levels was also noted. In addition, heart tissues histo-architecture displayed major presence of apoptosis and necrosis as confirmed by DNA degradation. However, supplementation with FWEP alleviated heart oxidative damage and genotoxicity. In this manner, ABTS radical-scavenging activity, linoleic acid oxidation tests and heart genomic and DNA nicking assay had proved FWEP strong antioxidant potential. In conclusion, FWEP provided significant protection against TMX-induced heart injury, and could be a useful and efficient agent against cardiotoxicity and atherosclerosis.

Modulatory effects of quercetin on liver histopathological, biochemical, hematological, oxidative stress and DNA alterations in rats exposed to graded doses of score 250

This study investigated the morphological, biochemical and molecular aspects of liver injury in rats after the exposure to difenoconazole and the protective effects of quercetin against hepatotoxicity and genotoxicity induced by this fungicide. Rats were given graded doses of difenoconazole associated or not to quercetin daily for 20 days. Our results showed a significant increase in PLT (platelets) and WBC (white blood cells) in rats treated with higher doses of difenoconazole (1/38 and 1/9 of LD50). However, a significant decrease in Hb (hemoglobin) rate and RBC (red blood cells) number in rats treated with higher doses of difenoconazole (1/38 and 1/9 of LD50) was obtained. Besides, difenoconazole treatment caused an increase in hepatic enzyme activities of alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH). Difenoconazole increased the levels of malondialdehyde (MDA) and advanced oxidation protein products (AOPPs), and decreased superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities and vitamin C levels in liver tissues compared to the control group. We also noted a degradation of nucleic acids, testifying difenoconazole genotoxicity. Changes in hepatic tissues were confirmed by histological findings. Co-administration of quercetin (20 mg/kg) improved hematological and biochemical parameters and showed a significant liver protective effect by decreasing MDA levels and producing advanced oxidation protein, along with increased antioxidative enzyme activities and vitamin C levels. Results were confirmed by the improvement of histological impairments. Thus, it appears that quercetin was effective in preventing acute liver injury induced by exposure to difenoconazole.

Biological properties of Alsidium corallinum and its potential protective effects against damage caused by potassium bromate in the mouse liver

In the course of searching for hepatoprotective agents from natural sources, the protective effect of chemical constituents of the marine red alga Alsidium corallinum (A. corallinum) against potassium bromate (KBrO3)-induced liver damage in adult mice was investigated. The in vitro antioxidant and antibacterial properties of A. corallinum were firstly investigated. Then, A. corallinum was tested in vivo for its potential protective effects against damage caused by KBrO3 in mice models divided into four groups: controls, KBrO3, KBrO3 + A. corallinum, and A. corallinum. Our results demonstrated the rich composition of A. corallinum in antioxidant compounds like phenolics, flavonoids, anthocyanins, polysaccharides, chlorophyll and carotenoids. Its antioxidant activity was also confirmed using β-carotene bleaching by linoleic acid assay, reducing sugar test and trolox equivalent antioxidant capacity. The ethanolic extract of A. corallinum also showed good inhibition of the tested bacteria. The coadministration of the red alga associated to the KBrO3 alleviated hepatotoxicity as monitored by the improvement of hepatic oxidative stress biomarkers and plasma biochemical parameters, when compared to the KBrO3-treated mice. These results were confirmed by the improvement of histological and molecular changes. Treatment with A. corallinum prevented liver damage induced by KBrO3, thus protecting the body against free radicals and reducing inflammation and hypercholesterolemia risks.

Naringenin protects cardiac hypercholesterolemia-induced oxidative stress and subsequent necroptosis in rats

BACKGROUND

In earlier studies, the supplementation of the natural compound Naringenin (NGEN), improved the liver oxidative and inflammatory status, which indicates its direct effect via inhibition of the nuclear factor κB pathway on high cholesterol-induced hepatic damages. In this regard, the present study highlights the mechanisms associated with the protective efficacy of NGEN in the heart tissue of hypercholesterolemic diet rats.

RESULTS

The animals exposed to a high cholesterol diet (HCD) for 90 days exhibited a significant increase in the levels of serum lactate dehydrogenase (LDH) and creatine kinase (CK) activities, nitric oxide (NO) levels, protein and lipid oxidative markers and cardiac lipids profile. Moreover, hypercholesterolemia decreased the levels of enzymatic and non enzymatic antioxidants associated with mitochondrial dysfunctions as proved by the decrease in the mitochondrial complexes in comparison to controls. Importantly, cholesterol-feeding significantly increased myocardial reactive oxygen species (ROS) and nuclear DNA damage and led to the activation of gene expression of the tumor necrosis factor-α (TNF-α) and receptor-interacting protein kinase 3 (RIP3) mRNA that contributed to the elucidation of cholesterol-induced necroptosis, a recently described type of programmed necrosis, in the cardiac tissue.

CONCLUSIONS

Our results show that the co-administration of NGEN (50 mg/kg/bw) in HCD rats improved all the altered parameters and provided insight into a possible molecular mechanism underlying NGEN suppression of necroptosis pathway in the heart.

Protective role of silymarin against manganese-induced nephrotoxicity and oxidative stress in rat

Metal toxicity may occur after exposure from many sources. Oxidative stress is thought to be involved in manganese-induced toxicity and leads to various health disorders. Silymarin (SIL), a natural flavonoid, has been reported to have many benefits and medicinal properties. The aim of this study was to assess the toxicity of manganese (Mn) on oxidative stress and DNA damage in the kidney of rats and its alleviation by SIL. Manganese was given orally in drinking water (20 mg MnCl2 /mL) with or without SIL administration (100 mg /kg intraperitoneally) for 30 days. Our data showed that SIL significantly prevented Mn induced nephrotoxicity, indicated by both diagnostic indicators of kidney injury like plasma urea, uric acid and creatinine and urinary electrolyte levels and by histopathological analysis. Moreover, Mn-induced profound elevation of the production of reactive oxygen species (ROS) and altered the levels of oxidative stress related biomarkers in kidney tissue. This is evidenced by the increase of lipid peroxidation, protein carbonylation, DNA fragmentation and urinary hydrogen peroxide, while, the activities of enzymatic antioxidant and glutathione level were decreased. Treatment with SIL reduced the alterations in the renal and urine markers, decreasing lipid peroxidation markers, increasing the antioxidant cascade and decreasing the Mn-induced damage. All these changes were supported by histopathological observations. These findings suggested that the inhibition of Mn-induced damage by SIL was due at least in part to its antioxidant activity and its capacity to modulate the oxidative damage.

Ultrasound stimulation induces microRNA expression changes that could be involved in sonication-induced apoptosis

PURPOSE

The purpose of this study is to investigate the involvement of microRNAs (miRNAs) in sonication-induced apoptosis.

METHODS

U937 cells derived from human leukemia were sonicated with 1-MHz ultrasound at 0.4 W/cm(2) and 10 % duty factor for 60 s, a condition inducing apoptosis. The total RNA was extracted from cells at various timings after sonication and subjected to microarray and real-time PCR for miRNA expression analyses.

RESULTS

Expression of several miRNAs was significantly affected by sonication. For miR-424* and miR-720, whose expressions were eminently decreased by sonication, cell lines overexpressing these miRNAs were established. Conversely, for miR-663B and miR-663, whose expressions were eminently increased by sonication, cell lines inhibiting these miRNA functions were established. When these cell lines were sonicated, a cell line inhibiting miR-663B function significantly increased sonication-induced apoptosis, suggesting this may be involved in cellular responses to sonication. Two genes that could induce apoptosis, KSR2 and CREBZF, were identified as potential target genes of miR-663B since potential target sequences on their 3' UTR mediated to decrease expression of a reporter gene.

CONCLUSION

These results suggest that miRNAs may be involved in cellular responses to ultrasound through their expression changes caused by sonication.

Identification of genes responsive to low intensity pulsed ultrasound in a human leukemia cell line Molt-4

We examined the gene expression of human leukemia Molt-4 cells treated with non-thermal low intensity pulsed ultrasound. Six hours after 0.3W/cm(2) pulsed ultrasound treatment, apoptosis (24+/-3.3%, mean+/-SD) with minimal cell lysis was observed. Of approximately 16,600 genes analyzed, BCL2-associated athanogene 3 (BAG3), DnaJ (Hsp40) homolog, subfamily B, member 1 (DNAJB1), heat shock 70 kDa protein 1B (HSPA1B), and heat shock 70 kDa protein 6 (HSPA6) showed increased levels of expression while isopentenyl-diphosphate delta isomerase (IDI1) and 3-hydroxy-3-methylglutaryl-coenzyme A synthase 1 (HMGCS1) showed decreased levels in the cells 3h after the ultrasound treatment. The expression levels of these six genes were confirmed by a real-time quantitative polymerase chain reaction. To our knowledge, this is the first report of DNA microarray analysis of genes that are differentially expressed in response to apoptosis induced by non-thermal low intensity pulsed ultrasound in human leukemia cells. The present results will provide a basis for further understanding of the molecular mechanisms of effects of not only low intensity pulsed ultrasound but also that of mechanical shear stress in the cells.

Apoptosis induced by the sonomechanical effects of low intensity pulsed ultrasound in a human leukemia cell line

To obtain an optimal condition for ultrasound (US)-induced apoptosis that could be useful for cancer therapy, we applied low intensity pulsed US to sonicate U937 cells in vitro. Cells were then incubated at different time intervals before measuring apoptosis. The apoptosis was assessed by DNA fragmentation and phosphatidylserine externalization. The pattern of the decrease in mitochondrial membrane potential was determined by flow cytometry. Optimal apoptosis (70.0+/-13.8%) with minimal lysis was attained with 1 MHz ultrasound 0.3 W/cm2, 10% duty factor at 100 Hz for 1 min) at 12 h after sonication. Lack of US-induced free radical detection and absence of Heme oxygenase-1, an intracellular oxidative stress marker, up-regulation in cells, suggest that sonomechanical, not sonochemical, effects are the main mechanism involved.

Pharmacologic modulation of the immune interaction between cytotoxic lymphocytes and ventricular myocytes

Numerous studies have demonstrated that immune effector mechanisms cause serious heart diseases, among which are heart transplant rejection, myocarditis, and the resulting dilated cardiomyopathy, as well as Chagas' disease. Whereas different effectors of the immune system can affect cardiac function, this review primarily focuses on the immune damage caused by cytotoxic T lymphocytes. The immune attack staged by cytotoxic T lymphocytes is carried out by one of two distinct modes of lymphocytotoxicity: (a) secretion of lytic granules containing the pore-forming protein perforin and a family of serine proteases (i.e., granzymes) and (b) interaction between the lymphocyte Fas ligand and the target cell Fas receptor. Ventricular myocytes challenged by the immune system sustain diverse intracellular changes, among which the rise in intracellular calcium ([Ca2+]i) constitutes an important contributor to myocyte dysfunction. Hence, this [Ca2+]i rise, which does not necessarily result in apoptosis, can affect cardiac function directly and indirectly. Importantly, the final outcomes of these perturbations vary markedly and depend on intracellular circumstances such as the magnitude of the absolute rise in [Ca2+]i and its temporal and spatial determinants, the metabolic status of the myocyte, as well as a fine balance between pro-apoptotic and anti-apoptotic factors. In view of the central role of [Ca2+]i rise in immune-mediated myocyte dysfunction and possibly cell death, this review addresses three topics related to the immune assault on the heart: (a) [Ca2+]i rise in affected myocytes; (b) the source for the [Ca2+]i rise; and (c) pharmacologic modification of the immune-mediated [Ca2+]i rise.

Nuclear translocation of granzyme B in target cell apoptosis

Granzyme B is the prototypic member of a family of serine proteases localized to the cytolytic granules of cytotoxic lymphocytes. Together with another granule protein, perforin, granzyme B is capable of inducing all aspects of apoptotic death in target cells. A number of granzyme B substrates have been identified and it has been demonstrated that granzyme B is responsible, directly or indirectly, for the morphological nuclear changes observed in target cell apoptosis, including DNA fragmentation. In an earlier study, we showed that granzyme B binds to a nuclear protein in a manner dependent on its enzymatic activity. Here, we demonstrate that granzyme B is translocated rapidly to the nucleus in cells that have been induced to undergo apoptosis by a granzyme-dependent process, and that translocation is dependent on caspase activity. Appearance of granzyme B in the nucleus of target cells precedes the detection of DNA fragmentation. Although not directly responsible for DNA fragmentation, these data suggest a nuclear role for granzyme B in target cell apoptosis. c-Abl nuclear functions.