Terminal Deoxyribonucleotidyl Transferase-mediated dUTP Nick-end Research Articles

A Novel Allele Encoding 7-Hydroxymethyl Chlorophyll a Reductase Confers Bacterial Blight Resistance in Rice.

Rice spotted leaf mutants are helpful to investigate programmed cell death (PCD) and defense response pathways in plants. Using a map-based cloning strategy, we characterized novel rice spotted leaf mutation splHM143 that encodes a 7-hydroxymethyl chlorophyll a reductase (OsHCAR). The wild-type (WT) allele could rescue the mutant phenotype, as evidenced by complementation analysis. OsHCAR was constitutively expressed at all rice tissues tested and its expression products localized to chloroplasts. The mutant exhibited PCD and leaf senescence with increased H2O2 (hydrogen peroxide) accumulation, increased of ROS (reactive oxygen species) scavenging enzymes activities and TUNEL (terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling) -positive nuclei, upregulation of PCD related genes, decreased chlorophyll (Chl) contents, downregulation of photosynthesis-related genes, and upregulation of senescence-associated genes. Besides, the mutant exhibited enhanced bacterial blight resistance with significant upregulation of defense response genes. Knockout lines of OsHCAR exhibited spotted leaf phenotype, cell death, leaf senescence, and showed increased resistance to the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo) coupled with upregulation of five pathogenesis-related marker genes. The overexpression of OsHCAR resulted in increased susceptibility to Xoo with decreased expression of pathogenesis-related marker genes. Altogether, our findings revealed that OsHCAR is involved in regulating cell death and defense response against bacterial blight pathogen in rice.

Salidroside induces apoptosis and autophagy in gastric cancer cells via regulation of mitogen-activated protein kinases signaling pathway

Background: Salidroside, an active ingredient of Rhodiola rosea, exhibits antiproliferative effect in gastric cancer (GC) cells. However, the involvement of salidroside in apoptosis and autophagy of GC cells has not been elucidated. Materials and Methods: Cell viability of BGC-823 cells was assessed by CCK-8 assay, and apoptosis was analyzed with terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling assay and flow cytometry. The apoptosis- and autophagy-associated proteins and mitogen-activated protein kinases (MAPKs) were determined by Western blot analysis. Autophagy was evaluated by green fluorescent protein-fused LC3 punctate formation. Results: Salidroside inhibited proliferation and promoted apoptosis and autophagy of BGC-823 cells in a dose-dependent manner. In addition, salidroside enhanced the phosphorylation of p38 MAPK, ERK1/2, and JNK. Furthermore, inhibition of MAPKs significantly abolished the effects of salidroside in BGC-823 cells. Conclusion: Salidroside induced apoptosis and autophagy of BGC-823 cells via activation of MAPK signaling pathway.

<p><strong>Antileishmanial apoptotic activity of <em>Nigella sativa</em> L. essential oil and thymoquinone triggers on <em>Leishmania tropica</em></strong></p>

Nigella sativa L., commonly called Black cumin, is well-known in folk medicine and numerous studies have shown its various pharmacological activities. In this study, we estimated the cytotoxic effects of N. sativa essential oil (NEO) and its major bioactive component Thymoquinone (TQ) on Leishmania tropica promastigotes that cause cutaneous leishmanias, and also observed the programmed cell death features. The extraction of NEO was done by hydro-distillation and analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). Antileishmanial activity of NEO and TQ was determined using 3-(4.5-dimethylthiazol-2-yl)-2.5-diphenyl tetrazolium bromide (MTT) assay and the obtained results are expressed as 50% inhibitory concentration (IC 50 ). The leishmanicidal activity of NEO and TQ was mediated via apoptosis as evidenced by in situ labelling of DNA fragments using terminal deoxyribonucleotidyltransferase-mediated dUTP nick end labelling (TUNEL) and cell cycle arrest at sub G 0 /G 1 phase. The IC 50 values were 5 µg/mL and 1.3 µg/mL, respectively. We noted a significant increase in DNA fragmentation in treated parasites with IC 50 of both NEO and TQ as well as a cell cycle arrest. These results revealed that NEO and TQ possess potential antileishmanial activity that mediated high possibility by programmed cell death.

Effects of sorafenib on fibroblast-like synoviocyte apoptosis in rats with adjuvant arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that is characterized by synovial inflammation and hyperplasia resulting from an imbalance between the proliferation and apoptosis of fibroblast-like synoviocytes (FLSs). Our previous study found that sorafenib had inhibitory effects in rats with adjuvant arthritis (AA). The present study investigated the role of sorafenib in the induction of AA FLS apoptosis in vitro. FLSs obtained from AA rats were cultured in vitro and identified. Cell apoptosis was detected using terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and annexin V-fluorescein isothiocyanate (FITC) and propidium iodide (PI) labeling methods. Real-time PCR and Western blotting assays were used to quantify the expression levels of Fas, Caspase-3, Mcl-1, NF-κB and C-jun gene products in AA FLSs. Our data revealed that sorafenib (4 μmol/L) induced apoptosis in AA FLSs, and flow cytometry analysis showed that AA FLSs treated with sorafenib (4 μmol/L) in vitro accumulated in early and late apoptosis. There were significant increases in the expression levels of Fas, Caspase-3 and Mcl-1, and significant decreases in NF-κB and C-jun expression in AA FLSs treated with sorafenib. In summary, these results demonstrate that sorafenib promotes AA FLS apoptosis, which may be related to the upregulation of Fas and Caspase-3 and downregulation of NF-κB and C-jun. All of these findings suggest that sorafenib exerts an inhibitory effect on AA rats in vivo via AA FLS apoptotic induction, which has potential therapeutic implications for RA.

LQB-118, an orally active pterocarpanquinone, induces selective oxidative stress and apoptosis in Leishmania amazonensis

The pterocarpanquinone LQB-118, previously demonstrated to be effective in vivo via oral delivery, was investigated for its mechanism in selective parasite killing. Oxidative stress in Leishmania amazonensis was analysed by evaluating reactive oxygen species (ROS) production (2',7'-dichlorodihydrofluorescein diacetate) and the loss of mitochondrial membrane potential (ΔΨm) using rhodamine, JC-1 and MitoCapture. Ultrastructural analysis was performed using transmission electron microscopy (TEM). DNA fragmentation was evaluated using terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL). Treatment with LQB-118 induced ROS production in the promastigotes of L. amazonensis in a concentration-dependent manner for the first 4 h and was sustained for 24 h. TEM analysis revealed several alterations typical of apoptosis. Promastigotes presented a reduction of ΔΨm after 24 h of incubation with 2.5 μM (18.7%), 5 μM (63.7%) or 10 μM (70.7%) LQB-118. A sub-G0/G1 cell cycle phenotype was observed in 21%-83% of the promastigotes incubated with 1.25-10 μM LQB-118. Concentration-dependent DNA fragmentation was observed in promastigotes treated with 2.5-10 μM LQB-118, and selective DNA fragmentation was observed in intracellular amastigotes after 72 h with 2.5 μM treatment. Our results suggest that LQB-118 selectively induces ROS-triggered and mitochondria-dependent apoptosis in this parasite.

Evaluation of reactive oxygen species (ROS) and DNA integrity assessment in cases of idiopathic male infertility

Background Studies suggest that reactive oxygen species (ROS) attack the integrity of DNA in the sperm nucleus by causing base modifications, DNA strand breaks, and chromatin cross-linking. Sperm DNA damage analysis may reveal hidden sperm DNA abnormalities in infertile men with normal standard semen analysis values who were diagnosed with idiopathic infertility. Aim of the work We explored the levels of ROS and their correlation with sperm DNA damage in patients with idiopathic male infertility. Patients and methods A total of 93 men were included in this study. Among them, 68 presented to our Andrology outpatient clinic with idiopathic infertility and were selected, and 25 were healthy fertile men, who were assigned to the control group. Both groups were subjected to the following laboratory investigations: semen analysis including peroxidase test, measurement of ROS levels by chemiluminescence assay, and sperm DNA damage assessment by terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). Results There were no significant differences in the semen parameters between idiopathic infertile men and controls. However, ROS and sperm DNA damage levels were significantly higher in idiopathic infertile men compared with controls ( P ͳ 0.001). In addition, the results showed a strong positive correlation between ROS levels and the percentage of sperm DNA damage ( P ͳ 0.001). Conclusion Traditional semen analysis does not reveal seminal defects at the molecular level that might be induced by ROS. Therefore, our results suggest that standard semen analysis should be coupled with measurement of ROS and assessment of DNA integrity in cases of idiopathic male infertility as even sperms with normal morphology and motility may harbor DNA damage.

Blockade of acid-sensing ion channels protects articular chondrocytes from acid-induced apoptotic injury

Acid-sensing ion channels (ASICs) are members of the degenerin/epithelial sodium channel (DEG/ENaC) protein superfamily and play a critical role in acid-induced cell injury. In this study, we examined whether drugs such as amiloride that block ASICs could attenuate acid-induced apoptotic injury to articular chondrocytes. Articular chondrocytes were isolated from Sprague-Dawley rats, and their phenotype was determined by toluidine blue and immunocytochemical staining. Articular chondrocyte viability assay was performed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). Apoptosis of chondrocytes was observed by the terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling method as well as propidium iodide labeling methods. Intracellular calcium ([Ca(2+)](i)) was analyzed by a Ca(2+)-imaging method. In addition, the expression levels of calpain and calcineurin in articular chondrocytes were examined by real-time PCR and immunocytochemical staining. The activity of caspase-3 was evaluated by spectrophotometric assays. Positive staining for glycosaminoglycan and collagen II was seen in articular chondrocytes. Blocking acid-sensing ion channels significantly decreased the cell death percentage and increased cell viability following acid exposure. After pretreated with amiloride, acid-induced [Ca(2+)](i) rises were reduced. Amiloride also inhibited calpain and calcineurin expression levels in acid-induced chondrocytes, and inhibited caspase-3 activity. The data presented in this study provided some experimental evidence that blocking ASICs could protect acid-induced apoptotic injury to chondrocytes.

Large human sperm vacuoles observed in motile spermatozoa under high magnification: nuclear thumbprints linked to failure of chromatin condensation

An embryo's ability to grow and implant can be improved by selection of a normal spermatozoon with a vacuole-free head. However, large vacuoles in spermatozoa have yet to be fully characterized. The present study aimed to determine whether these vacuoles are of nuclear, membrane and/or acrosomal origin. We studied 15 infertile patients with differing sperm profiles. For each sperm sample, we used high-magnification (×10 000) contrast microscopy to select and assess 30 normal 'top' spermatozoa and 30 spermatozoa with a large sperm-head vacuole (≥ 25% of the head's cross-sectional area). We subsequently analysed the spermatozoa's degree of chromatin condensation (aniline blue staining), DNA fragmentation (terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labelling assay) and chromosome content (fluorescence in situ hybridization X,Y,18). Atomic force microscopy enabled us to map the plasma sperm membrane in detail. Three-dimensional deconvolution microscopy enabled us to reconstruct images of the nucleus and acrosome in 'top' and 'vacuolated' spermatozoa. We studied a total of 450 'top' spermatozoa and 450 vacuolated spermatozoa. The rate of non-condensed chromatin was higher for 'vacuolated' spermatozoa than for 'top' spermatozoa (36.2 ± 1.9 versus 7.6 ± 1.3%, respectively; P < 0.0001). 'Top' and 'vacuolated' spermatozoa did not differ significantly in terms of DNA fragmentation (0.7 ± 0.4 versus 1.3 ± 0.4% respectively; P = 0.25) or aneuploidy (1.1 ± 0.5 versus 2.2 ± 0.7% respectively; P = 0.21). The majority of aneuploid spermatozoa (9 out of 15) lacked chromatin condensation. In all vacuolated spermatozoa, the acrosome was intact, the plasma membrane was sunken but intact and the large vacuole was identified as an abnormal, 'thumbprint'-like nuclear concavity covered by acrosomal and plasmic membranes. The large vacuole appears to be a nuclear 'thumbprint' linked to failure of chromatin condensation.

Granzyme B-induced and Caspase 3-dependent Cleavage of Gelsolin by Mouse Cytotoxic T Cells Modifies Cytoskeleton Dynamics

Granule-associated perforin and granzymes (gzms) are key effector molecules of cytotoxic T lymphocytes (Tc cells) and natural killer cells and play a critical role in the control of intracellular pathogens and cancer. Based on the notion that many gzms, including A, B, C, K, H, and M exhibit cytotoxic activity in vitro, all gzms are believed to serve a similar function in vivo. However, more recent evidence supports the concept that gzms are not unidimensional but, rather, possess non-cytotoxic potential, including stimulation of pro-inflammatory cytokines and anti-viral activities. The present study shows that isolated mouse gzmB cleaves the actin-severing mouse protein, cytoplasmic gelsolin (c-gelsolin) in vitro. However, when delivered to intact target cells by ex vivo immune Tc cells, gzmB mediates c-gelsolin proteolysis via activation of caspases 3/7. The NH(2)-terminal c-gelsolin fragment generated by either gzmB or caspase 3 in vitro constitutively severs actin filaments without destroying the target cells. The observation that gzmB secreted by Tc cells initiates a caspase cascade that disintegrates the actin cytoskeleton in target cells suggests that this intracellular process may contribute to anti-viral host defense.

Apoptosis-like death in Leishmania donovani promastigotes induced by diospyrin and its ethanolamine derivative

Previous studies have demonstrated that diospyrin ( 1), a quinonoid plant product, can inhibit the growth of Leishmania donovani parasites. Here, several derivatives of 1 were evaluated by the MTT assay and it was observed that the ethanolamine analogue ( 10) exhibited maximum cytotoxicity [50% inhibitory concentration (IC 50) = 2.9 μM] against L. donovani promastigotes. Subsequently, the mode of cell death in promastigotes was investigated through externalisation of membrane-associated phosphatidylserine, mitochondrial membrane depolarisation, DNA laddering and in situ labelling of DNA fragmentation by terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) methods. Whilst both 1 and 10 were found to induce apoptosis-like death in promastigotes, the effect of 10 was evidently stronger even at a lower concentration. Hence, the ethanolamine derivative ( 10) of diospyrin ( 1) may be a prospective ‘lead’ for the development of novel cytotoxic agents inducing apoptosis in L. donovani parasites.

Activation of Akt/GSK-3β signaling pathway is involved in intermedin1–53 protection against myocardial apoptosis induced by ischemia/reperfusion

Intermedin (IMD) is a novel member of the calcitonin/calcitonin gene-related peptide family. We investigated the cardioprotective mechanism of IMD(1-53) in the in vivo rat model of myocardial ischemia/reperfusion (I/R) injury and in vitro primary neonatal cardiomyocyte model of hypoxia/reoxygenation (H/R). Myocardial infarct size was measured by 2,3,5-triphenyl tetrazolium chloride staining. Cardiomyocyte viability was determined by trypan blue staining, cell injury by lactate dehydrogenase (LDH) leakage, and cardiomyocyte apoptosis by terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling assay, Hoechst staining, gel electrophoresis and caspase 3 activity. The translocation of mitochondrial cytochrome c of myocardia and expression of apoptosis-related factors Bcl-2 and Bax, phosphorylated Akt and phosphorylated GSK-3beta were determined by western blot analysis. IMD(1-53) (20 nmol/kg) limited the myocardial infarct size in rats with I/R; the infarct size was decreased by 54%, the apoptotic index by 30%, and caspase 3 activity by 32%; and the translocation of cytochrome c from mitochondria to cytosol was attenuated. IMD(1-53) increased the mRNA and protein expression of Bcl-2 and ratio of Bcl-2 to Bax by 81 and 261%, respectively. IMD(1-53) (1 x 10(-7) mol/L) inhibited the H/R effect in cardiomyocytes by reducing cell death by 43% and LDH leakage by 16%; diminishing cellular apoptosis; decreasing caspase 3 activity by 50%; and increasing the phosphorylated Akt and GSK-3beta by 41 and 90%, respectively. The cytoprotection of IMD(1-53) was abolished with LY294002, a PI3K inhibitor. In conclusion, IMD(1-53) exerts cardioprotective effect against myocardial I/R injury through the activation of the Akt/GSK-3beta signaling pathway to inhibit mitochondria-mediated myocardial apoptosis.

Activation of Akt/GSK-3β signaling pathway is involved in intermedin1-53 protection against myocardial apoptosis induced by ischemia/reperfusion

Intermedin (IMD) is a novel member of the calcitonin/calcitonin gene-related peptide family. We investigated the cardioprotective mechanism of IMD(1-53) in the in vivo rat model of myocardial ischemia/reperfusion (I/R) injury and in vitro primary neonatal cardiomyocyte model of hypoxia/reoxygenation (H/R). Myocardial infarct size was measured by 2,3,5-triphenyl tetrazolium chloride staining. Cardiomyocyte viability was determined by trypan blue staining, cell injury by lactate dehydrogenase (LDH) leakage, and cardiomyocyte apoptosis by terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling assay, Hoechst staining, gel electrophoresis and caspase 3 activity. The translocation of mitochondrial cytochrome c of myocardia and expression of apoptosis-related factors Bcl-2 and Bax, phosphorylated Akt and phosphorylated GSK-3beta were determined by western blot analysis. IMD(1-53) (20 nmol/kg) limited the myocardial infarct size in rats with I/R; the infarct size was decreased by 54%, the apoptotic index by 30%, and caspase 3 activity by 32%; and the translocation of cytochrome c from mitochondria to cytosol was attenuated. IMD(1-53) increased the mRNA and protein expression of Bcl-2 and ratio of Bcl-2 to Bax by 81 and 261%, respectively. IMD(1-53) (1 x 10(-7) mol/L) inhibited the H/R effect in cardiomyocytes by reducing cell death by 43% and LDH leakage by 16%; diminishing cellular apoptosis; decreasing caspase 3 activity by 50%; and increasing the phosphorylated Akt and GSK-3beta by 41 and 90%, respectively. The cytoprotection of IMD(1-53) was abolished with LY294002, a PI3K inhibitor. In conclusion, IMD(1-53) exerts cardioprotective effect against myocardial I/R injury through the activation of the Akt/GSK-3beta signaling pathway to inhibit mitochondria-mediated myocardial apoptosis.

COOH-Terminal Truncated HBV X Protein Plays Key Role in Hepatocarcinogenesis

X protein (HBx), a product of hepatitis B virus, has been closely associated with the development of hepatocellular carcinoma (HCC). Based on observations that the COOH-terminal truncated HBx was frequently detected in HCC, the aim of this study is to evaluate the function of COOH-terminal truncated HBx in hepatocarcinogenesis. Expression pattern of HBx was analyzed by immunohistochemistry on tissue microarray containing 194 pairs of HCCs and their matched nontumor liver tissues. MIHA and HepG2 cells transfected with full-length (X2) and COOH-terminal truncated HBx (X1) were tested for their ability to grow in soft agar and form tumors in vivo. Proliferation and apoptosis were assessed using 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide inner salt and terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling assays, respectively. To gain additional insight, the expression profile of HepG2-X2 and HepG2-X1 were compared using cDNA microarray. COOH-terminal truncated HBx was frequently detected in HCCs (79.3%, n = 111), and our in vitro and in vivo studies showed that the truncated rather than the full-length HBx could effectively transform immortalized liver cell line MIHA. Interestingly, expression profiling revealed differential expression of key genes implicated in the control of cell cycle and apoptosis. These findings strongly suggest that the COOH-terminal truncated HBx plays a critical role in the HCC carcinogenesis via the activation of cell proliferation.

Mechanism of Fibroblast‐Like Synoviocyte Apoptosis Induced by Recombinant Human Endostatin in Rats with Adjuvant Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by pronounced synovial hyperplasia, in which there may be an imbalance between the growth and death of fibroblast-like synoviocytes (FLS). The present study was undertaken to examine the effect of recombinant human endostatin (rhEndostatin) on FLS apoptosis in experimental RA. Adjuvant arthritis (AA) was induced in male Sprague Dawley (SD) rats. Using cultured AA FLS obtained from these rats, the apoptosis process was measured by terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) as well as Annexin V-fluorescein isothiocyanate (FITC) and propidium iodide (PI) labeling methods. In addition, the expression levels of the Fas, c-jun, NFkappaB, and caspase-3 gene products in synovial tissues were quantified by quantitative real-time polymerase chain reaction (qPCR) and/or Western blotting assays. Our data revealed that rhEndostatin induced apoptosis in AA FLS. The number and signal density of TUNEL-positive cells were significantly increased in rats treated with rhEndostatin (2.5 mg/kg). The percentage of Annexin V-FITC-positive cells was 6.67% after treatment with rhEndostatin at 25 microg/mL for 48 hr, compared with only 3.32% among untreated control cells. There were significant increases in Fas mRNA, c-jun mRNA, c-Jun protein, and caspase-3 (p20) protein in AA synovial tissues treated with rhEndostatin (2.5 mg/kg), whereas no significant difference in NFkappaB expression was detected between treated and untreated tissues. These findings indicate that rhEndostatin has a therapeutic effect on RA by inducing FLS apoptosis, which is strongly associated with increased expression of Fas, c-jun, and caspase-3, but not NFkappaB.

Correlation between DNA damage and sperm parameters: a prospective study of 1,633 patients

To investigate DNA fragmentation by using terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling in relation to World Health Organization parameters and computer-aided sperm analysis (CASA) in sperm to determine the possibility of obtaining a correlation among CASA parameters, sperm morphology, and DNA fragmentation. Sperm analysis according to World Health Organization parameters, terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) for sperm DNA fragmentation, and CASA for sperm movement. Prospective study. All the patients were under clinical management, consulting for hypofertility at a fertility center in France. One thousand six hundred thirty-three men who were referred for infertility investigation, including a complete sperm analysis. Sperm analysis and DNA damage testing. Sperm morphology, DNA fragmentation, and movement characteristics. One third of the patients had a TUNEL rate of >30%. Analysis of the 21 semen parameters tested revealed that 7 of them were significantly correlated with the TUNEL results. World Health Organization sperm parameters and DNA damage are complementary, rather than strongly linked. This should be considered to more fully understand the paternal contribution in assisted reproductive technologies failures.

Reactive oxygen species, total antioxidant concentration of seminal plasma and their effect on sperm parameters and outcome of IVF/ICSI patients

The purpose of this study was to determine and compare the concentration of reactive oxygen species (ROS) and total antioxident (TAS) in seminal plasma of IVF (in vitro fertilization) and ICSI patients, to establish their effect on sperm quality (count, vitality, HOS, morphology, maturity, DNA strand breaks) and assess the fertilization potential of spermatozoa and IVF/ICSI outcome. IVF/ICSI patients (n = 48) 26 IVF and 22 ICSI were included in this study. A spermiogram was generated from each patient one-hour post ejaculation and smears were made from each semen sample to evaluate the morphology, sperm maturity (Chromomycin CMA3) and DNA strand breaks (Terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labelling, TUNEL-assay). In both groups a negative correlation was found between ROS concentration in seminal plasma and sperm vitality (r= -0.111; P = 0.453); membrane integrity and morphology (-0.141; P = 0.340) and fertilization rate (r = -0.0290; P=0.045). However, TAS in seminal plasma correlated positive with fertilization rate (r = 0.081; P = 0.584). In addition, an inverse correlation was found between sperm DNA strand breaks (TUNEL-test) and spermatozoa global and progressive motility, vitality, and membrane integrity. Furthermore, the mean percentage of normal condensed spermatozoa (CMA3) was significantly higher (P = 0.0001) in patients undergoing IVF compared to ICSI. Spermatozoa of male ICSI patients were more susceptible to acid denaturation (acridine orange staining) compared to spermatozoa of male IVF patients (P = 0.041). However, ROS concentration was higher in IVF patients compared to ICSI patients (94.73 +/- 102.84 vs. 54.78 +/- 39.83 micromol/l, whilst TAS levels (1.43 +/- 0.28 vs. 1.53 +/- 0.22) and fertilization rate (67. 26 vs. 67.26) were similar in both groups. ROS concentration and other sperm parameters were higher in IVF compared to ICSI patients. TAS concentration was comparable between the two groups. However, the fertilization rate was smilar in IVF and ICSI patients. Therefore, ROS concentration in seminal plasma affects the quality of spermatozoa but does not affect the fertilization rate in IVF/ICSI cycles.

Artemisinin triggers induction of cell-cycle arrest and apoptosis in Leishmania donovani promastigotes

A major impediment to effective anti-leishmanial chemotherapy is the emergence of drug resistance, especially to sodium antimony gluconate, the first-line treatment for leishmaniasis. Artemisinin, a sesquiterpene lactone isolated from Artemisia annua, is an established anti-malarial compound that showed anti-leishmanial activity in both promastigotes and amastigotes, with IC(50) values of 160 and 22 microM, respectively, and, importantly, was accompanied by a high safety index (>22-fold). The leishmanicidal activity of artemisinin was mediated via apoptosis as evidenced by externalization of phosphatidylserine, loss of mitochondrial membrane potential, in situ labelling of DNA fragments by terminal deoxyribonucleotidyltransferase-mediated dUTP nick end labelling (TUNEL) and cell-cycle arrest at the sub-G(0)/G(1) phase. Taken together, these data indicate that artemisinin has promising anti-leishmanial activity that is mediated by programmed cell death and, accordingly, merits consideration and further investigation as a therapeutic option for the treatment of leishmaniasis.

H2S, Endoplasmic Reticulum Stress, and Apoptosis of Insulin-secreting Beta Cells

Cystathionine gamma-lyase (CSE) is a key enzyme in the trans-sulfuration pathway, which uses L-cysteine to produce hydrogen sulfide (H2S). Functional changes of pancreatic beta cells induced by endogenous H2S have been reported, but the effect of the CSE/H2S system on pancreatic beta cell survival has not been known. In this study, we demonstrate that H2Sat physiologically relevant concentrations induced apoptosis of INS-1E cells, an insulin-secreting beta cell line. Transfection of INS-1E cells with a recombinant defective adenovirus containing the CSE gene (Ad-CSE) resulted in a significant increase in CSE expression and H2S production. Ad-CSE transfection also stimulated apoptosis. The other two end products of CSE-catalyzed enzymatic reaction, ammonium and pyruvate, had no effects on INS-1E cell apoptosis, indicating that overexpression of CSE may stimulate INS-1E cell apoptosis via increased endogenous production of H2S. Both exogenous H2S (100 microM) and Ad-CSE transfection inhibited ERK1/2 but activated p38 MAPK. Interestingly, BiP and CHOP, two indicators of endoplasmic reticulum (ER) stress, were up-regulated in H2S-and CSE-mediated apoptosis in INS-1E cells. After suppressing CHOP mRNA expression, H2S-induced apoptosis of INS-1E cells was significantly decreased. Inhibition of p38 MAPK, but not of ERK1/2, inhibited the expression of BiP and CHOP and decreased H2S-stimulated apoptosis, suggesting that p38 MAPK activation functions upstream of ER stress to initiate H2S-induced apoptosis. It is concluded that H2S induces apoptosis of insulin-secreting beta cells by enhancing ER stress via p38 MAPK activation. Our findings may help unmask a novel role of CSE/H2S system in regulating pancreatic functions under physiological condition and in diabetes.

Involvement of protein kinase B and mitogen-activated protein kinases in experimental normothermic liver ischaemia–reperfusion injury

This study evaluated the role of protein kinase B (PKB), phosphatidylinositol 3-kinase (PI3-K), Bcl-2-associated death protein (BAD) and mitogen-activated protein kinases (MAPKs) in normothermic ischaemia-reperfusion (IR)-induced apoptosis in rat liver. Rats were divided into two groups that received either phosphate-buffered saline (control) or the caspase inhibitor Z-Asp-2,6-dichorobenzoyloxymethylketone (Z-Asp-cmk), injected intravenously 2 min before the induction of 120 min of normothermic liver ischaemia. Liver apoptosis was assessed by the terminal deoxyribonucleotidyltransferase-mediated dUTP nick end labelling (TUNEL) method. PI3-K, PKB, BAD and MAPK activities were measured in ischaemic and non-ischaemic lobes at various times after reperfusion. The number of TUNEL-positive cells was significantly decreased after pretreatment with Z-Asp-cmk. In controls, PI3-K and PKB activities and BAD phosphorylation were inhibited in ischaemic liver lobes. The MAPKs (extracellular signal-regulated kinases, c-Jun N-terminal kinase and p38) showed different patterns of activation during IR. PKB activity was not modified by pretreatment with Z-Asp-cmk. Induction of apoptosis during IR liver injury might be triggered by inactivation of the antiapoptotic PI3-K-PKB pathway and activation of the proapoptotic MAPKs.

Increased sperm DNA damage in patients with varicocele: relationship with seminal oxidative stress

The pathophysiology of the testicular damage in varicocele has not been completely understood. Oxidative stress and related sperm DNA damage have been identified as significant causes of male infertility. The current study was designed to determine the extent of sperm nuclear DNA damage in patients with varicocele and to examine its relationship with oxidative stress. Semen samples from 55 patients with clinical varicocele and 25 normozoospermic donors were examined. Varicocele sperm samples were classified as normal or abnormal according to World Health Organization guidelines. Sperm DNA damage was evaluated by the sperm chromatin structure assay/flow cytometry and by the terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) assay. Levels of reactive oxygen species (ROS) and total antioxidant capacity were assessed by a chemiluminescence assay. DNA fragmentation index (DFI) (percentage of sperm with denatured DNA) values and the percentage of TUNEL-positive cells were significantly greater in patients with varicocele, either with normal (DFI, 20.7 +/- 4.0; TUNEL positive, 26.1 +/- 3.2) or with abnormal (DFI, 35.5 +/- 9.0; TUNEL positive, 32.2 +/- 4.1) semen profile, compared with controls (DFI, 7.1 +/- 0.9; TUNEL positive, 14.2 +/- 1.2). Similarly, ROS levels were significantly higher (P < 0.01) in both groups of patients with varicocele. The presence of a varicocele is associated with high levels of DNA-damage spermatozoa even in the presence of normal semen profile. The results also indicate that oxidative damage is associated with sperm DNA damage in these patients.