Synergistic effect of flavonoids combined with antivenom on neutralisation of Naja naja venom

Objective: To evaluate the neutralizing effects of flavonoids on snake venom toxicity by stand-alone and combinatorial approaches. Methods: Synthetic flavonoids were assessed, either individually or in combination with antivenom, for their neutralization of phospholipase A

Neutralizing potential of Rauvolfia serpentina root extract against Naja naja venom

Snake bites are a serious health hazard occurs throughout the world especially in tropical countries like India. Anti-Snake Venom Serum is the only remedy available to treat snake bite victims successfully till date. Infusion of ASV may lead to adverse reactions ranging from severe itching of the skin, hives to potentially serious allergic reactions. Considering all above difficulties research workers all over the world is constantly in search of a cheap and readily available easy formulate remedy for treating snake bite victims. In present study aqueous extract of Rauvolfia serpentina root was checked for the antidote properties against Naja naja venom by in vitro and in vivo methods. Various in vitro neutralization tests like Acetyl cholinesterase, Protease and ATPase activity of Naja naja venom were carried out and the root extract was neutralized all the toxic effects induced by the venom. The in vivo assessment of venom lethality (LD50) of Naja naja venom was found to be 0.301 µg. The aqueous root extract was effectively neutralized the venom lethality and effective dose (ED50) was found to be 12.88 mg/ 3LD50 of Naja naja venom. LC-MS analysis from root extract of Rauvolfia serpentina was done for confirmation of the bioactive compounds.

Anticancer potential of nanogold conjugated toxin GNP-NN-32 from Naja naja venom

Background: Cancer is the second most common fatal disease in the world, behind cardiovascular disorders in the first place. It accounts for around 0.3 million deaths per year in India due to the lack of proper diagnostic facilities, prevention and treatment. Current therapeutic methods do not provide adequate protection and affect normal cells along with cancerous ones. Thus, there is a need for some alternative therapeutic strategy, preferably from natural products, which have been traditionally used for treatment of various diseases in the country. Methods: In this study, we have conjugated purified NN-32 toxin from Naja naja venom with gold nanoparticles and its anticancer potential was evaluated against human breast cancer cell lines. UV-Vis spectroscopy, dynamic light scattering, transmission electron microscopy, atomic force microscopy and zeta potential analysis were the techniques used for characterization of GNP-NN-32. Results: GNP-NN-32 showed dose- and time-dependent cytotoxicity against breast cancer cell lines (MCF-7 and MDA-MB-231). NN-32 and GNP-NN-32 induced apoptosis in both breast cancer cell lines. The results of CFSE cell proliferation study revealed that NN-32 and GNP-NN-32 arrested cell division in both MCF-7 and MDA-MB-231 cell lines resulting in inhibition of proliferation of these cancer cells. Conclusion: GNP-NN-32 showed an anticancer potential against human breast cancer cell lines. Analysis of detailed chemical characterization along with its cytotoxic property might help to perceive a new dimension of the anti-cancer potential of GNP-NN-32 that will enhance its biomedical function in near future.(AU)

Hematological and plasma biochemical parameters in a wild population of Naja naja (Linnaeus, 1758) in Sri Lanka

Background Hematological studies of any animal species comprise an important diagnostic method in veterinary medicine and an essential tool for the conservation of species. In Sri Lanka, this essential technique has been ignored in studies of many species including reptiles. The aim of the present work was to establish a reference range of hematological values and morphological characterization of wild spectacled cobras (Naja naja) in Sri Lanka in order to provide a diagnostic tool in the assessment of health condition in reptiles and to diagnose diseases in wild populations. Methods Blood samples were collected from the ventral caudal vein of 30 wild-caught Naja naja (18 males and 12 females). Hematological analyses were performed using manual standard methods. Results Several hematological parameters were examined and their mean values were: red blood cell count 0.581 ± 0.035 × 106/μL in males; 0.4950 ± 0.0408 × 106/μL in females; white blood cell count 12.45 ± 1.32 × 103/μL in males; 11.98 ± 1.62 × 103/μL in females; PCV (%) in males was 30.11 ± 1.93 and in females was 23.41 ± 1.67; hemoglobin (g/dL) was 7.6 ± 0.89 in males and 6.62 ± 1.49 in females; plasma protein (g/dL) was 5.11 ± 0.75 in males and 3.25 ± 0.74 in females; whereas cholesterol (mg/mL) was 4.09 ± 0.12 in males and 3.78 ± 0.42 in females. There were no significant differences in hematological parameters between the two genders except for erythrocyte count, thrombocyte count, hematocrit, hemoglobin, plasma protein, percentage of azurophil and heterophil. Intracellular parasites were not found in any of the studied specimens. Conclusion Hematological and plasma biochemical parameters indicated a difference between geographically isolated populations and some values were significantly different between the two genders. These hematological results provide a reference range for Sri Lankan population of adult Naja naja.(AU)

Hematological and plasma biochemical parameters in a wild population of Naja naja (Linnaeus, 1758) in Sri Lanka

Abstract Background Hematological studies of any animal species comprise an important diagnostic method in veterinary medicine and an essential tool for the conservation of species. In Sri Lanka, this essential technique has been ignored in studies of many species including reptiles. The aim of the present work was to establish a reference range of hematological values and morphological characterization of wild spectacled cobras (Naja naja) in Sri Lanka in order to provide a diagnostic tool in the assessment of health condition in reptiles and to diagnose diseases in wild populations. Methods Blood samples were collected from the ventral caudal vein of 30 wild-caught Naja naja (18 males and 12 females). Hematological analyses were performed using manual standard methods. Results Several hematological parameters were examined and their mean values were: red blood cell count 0.581 ± 0.035 × 106/L in males; 0.4950 ± 0.0408 × 106/L in females; white blood cell count 12.45 ± 1.32 × 103/L in males; 11.98 ± 1.62 × 103/L in females; PCV (%) in males was 30.11 ± 1.93 and in females was 23.41 ± 1.67; hemoglobin (g/dL) was 7.6 ± 0.89 in males and 6.62 ± 1.49 in females; plasma protein (g/dL) was 5.11 ± 0.75 in males and 3.25 ± 0.74 in females; whereas cholesterol (mg/mL) was 4.09 ± 0.12 in males and 3.78 ± 0.42 in females. There were no significant differences in hematological parameters between the two genders except for erythrocyte count, thrombocyte count, hematocrit, hemoglobin, plasma protein, percentage of azurophil and heterophil. Intracellular parasites were not found in any of the studied specimens. Conclusion Hematological and plasma biochemical parameters indicated a difference between geographically isolated populations and some values were significantly different between the two genders. These hematological results provide a reference range for Sri Lankan population of adult Naja naja.

In vitro Antibacterial Activity of Snake Venom, Naja naja from Bangladesh.

Aim: Snake venom is a source of antimicrobial peptides. Composition as well as activities of venom may vary based on geographic region and notably the antimicrobial activity of the venom of Naja naja from Bangladesh has not yet been tested. Thus, in this study, investigated the antibacterial activity of the venom of snake Naja naja from Bangladesh against two bacterial strains. Place and Duration of Study: The study was carried out in protein science laboratory, Department of Genetic Engineering and Biotechnology, University of Rajshahi, Bangladesh, between July 2012 to December 2012. Methods: Luria agar medium was used to culture the E. coli and B. thuringiensis strains of bacteria. Disc diffusion method was used to carry out the test of antibacterial sensitivity. Discs prepared by Whatman No. 1 filter paper were soaked with different doses (25, 50, 75 and 100 μg) of crude venom and placed on the cultured bacterial plates along with two standard antimicrobial antibiotic discs. After overnight incubation at 37ºC, antibacterial activity of venom was measured by inhibition zone observed around the discs in the plates. Results: Application of 75 and 100 μg of crude venom showed antibacterial activity against E. coli, whereas only 100 μg crude venom showed little antibacterial activity against B. thuringiensis. Conclusion: The results of this study revealed that the crude venom of Naja naja may contain some proteins responsible for antibacterial activity and the quantity of antibacterial peptides might be lower in venom than other components.

Hematology and plasma biochemistry of wild-caught Indian cobra Naja naja (Linnaeus, 1758)

Hematology and plasma biochemistry parameters are useful in the assessment and management of snake physiological status. Although reference ranges are readily available for many snake species, they are lacking for most venomous ophidians. We determined hematology and plasma biochemistry reference ranges for the wild-caught Indian cobra, Naja naja.

Hematology and plasma biochemistry of wild-caught Indian cobra Naja naja (Linnaeus, 1758)

Hematology and plasma biochemistry parameters are useful in the assessment and management of snake physiological status. Although reference ranges are readily available for many snake species, they are lacking for most venomous ophidians. We determined hematology and plasma biochemistry reference ranges for the wild-caught Indian cobra, Naja naja.

Mad, bad and dangerous to know: the biochemistry, ecology and evolution of slow loris venom

Only seven types of mammals are known to be venomous, including slow lorises (Nycticebus spp.). Despite the evolutionary significance of this unique adaptation amongst Nycticebus, the structure and function of slow loris venom is only just beginning to be understood. Here we review what is known about the chemical structure of slow loris venom. Research on a handful of captive samples from three of eight slow loris species reveals that the protein within slow loris venom resembles the disulphide-bridged heterodimeric structure of Fel-d1, more commonly known as cat allergen. In a comparison of N. pygmaeus and N. coucang, 212 and 68 compounds were found, respectively. Venom is activated by combining the oil from the brachial arm gland with saliva, and can cause death in small mammals and anaphylactic shock and death in humans. We examine four hypotheses for the function of slow loris venom. The least evidence is found for the hypothesis that loris venom evolved to kill prey. Although the venom's primary function in nature seems to be as a defense against parasites and conspecifics, it may also serve to thwart olfactory-orientated predators. Combined with numerous other serpentine features of slow lorises, including extra vertebra in the spine leading to snake-like movement, serpentine aggressive vocalisations, a long dark dorsal stripe and the venom itself, we propose that venom may have evolved to mimic cobras (Naja sp.). During the Miocene when both slow lorises and cobras migrated throughout Southeast Asia, the evolution of venom may have been an adaptive strategy against predators used by slow lorises as a form of Müllerian mimicry with spectacled cobras.(AU)

Mad, bad and dangerous to know: the biochemistry, ecology and evolution of slow loris venom

Only seven types of mammals are known to be venomous, including slow lorises (Nycticebus spp.). Despite the evolutionary significance of this unique adaptation amongst Nycticebus, the structure and function of slow loris venom is only just beginning to be understood. Here we review what is known about the chemical structure of slow loris venom. Research on a handful of captive samples from three of eight slow loris species reveals that the protein within slow loris venom resembles the disulphide-bridged heterodimeric structure of Fel-d1, more commonly known as cat allergen. In a comparison of N. pygmaeus and N. coucang, 212 and 68 compounds were found, respectively. Venom is activated by combining the oil from the brachial arm gland with saliva, and can cause death in small mammals and anaphylactic shock and death in humans. We examine four hypotheses for the function of slow loris venom. The least evidence is found for the hypothesis that loris venom evolved to kill prey. Although the venom's primary function in nature seems to be as a defense against parasites and conspecifics, it may also serve to thwart olfactory-orientated predators. Combined with numerous other serpentine features of slow lorises, including extra vertebra in the spine leading to snake-like movement, serpentine aggressive vocalisations, a long dark dorsal stripe and the venom itself, we propose that venom may have evolved to mimic cobras (Naja sp.). During the Miocene when both slow lorises and cobras migrated throughout Southeast Asia, the evolution of venom may have been an adaptive strategy against predators used by slow lorises as a form of Müllerian mimicry with spectacled cobras.

Effect of Naja naja Laurenti shed skin extract on estrous cycle, hormone - cytokine profiles, histopathology of ovary and uterus of Swiss albino mice.

The snake shed skin though considered as biological waste products have been mentioned in folk and traditional medicine for treatment of ailments like skin disorders, parturition problems etc. Shedded skin extract (5 mg.kg-1, sc) did not produce any change in the estrous cycle of normal cycling female mice. However in 10 mg.kg-1, sc dose, the extract caused a temporary cessation of the estrous cycle at diestrous phase in normal cycling female mice for 10 days. SSAE (10 mg.kg-1, sc) caused a significant change in the level of LH, FSH, progesterone, estradiol, IL-1β, IL-6 and TNF-α. Histopathology of uterus and ovary showed structural disorientation in both. The results substantiate the influence of snake shed skin in mice reproductive cycle.

Determination of molecular mass and partial peptide confirmation of short neurotoxins using chromatographic techniques and reverse phase HPLC.

The aim of present work was to investigate the purification of a novel protein (low molecular weight) from Indian cobra Naja naja by Cation exchange chromatography on CM-Sephadex C-25 and followed by Gelfiltration chromatography on Sephadex G-100. Fraction numbers 26, 27, and 28 were obtained from CM Sephadex C-25. From all the fractions, the protein concentration was calculated and it was applied onto the Sephadex G-100 Gelfiltration chromatography. Fraction No-11 obtained from Sephadex G-100 was used for the determination of molecular weight of the short neurotoxins by SDS-PAGE and Matrix- Assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF). This SDS-PAGE is corresponding to the gel filtration chromatography which resolved a thick band of ~6-7 kDa proteins, and the MALDI-TOF resolved 6668.530, 7447.438 and 19928.929 Da. Further, this fraction was selected for preparative HPLC by using C18 column, in which two major peaks (retention time 30.793 and 32.846) were found. The peak with retention time of 30.793 was preferred for molecular mass determination by MALDI-TOF showed a single sharp peak of 6815.471 Da. It was digested with trypsin enzymatic cleavage, which explored approximately 26 peptides and their masses were renowned. The scores of all these 26 peptides were compared with online mascot analysis and BLAST sequence and it did not match with any other peptides and proteins. Among these 26 peptides, since only two peptides score as 886.648 and 943.690 Da were identical with short neurotoxin -1 from Naja oxiana, and short neurotoxin -3 from Naja mossambica. Moreover the 6815.471 Da protein was used for hemolytic activity and it did not induce RBC lysis. All this observations suggested that the newly purified protein is a short neurotoxin. This essential information will support us to find out the structural information of short neurotoxin for its application in anti-venom development, antitumor and also for analgesic effects.

Preparation and characterization of immunoglobulin yolk against the venom of Naja naja atra.

Chinese Cobra (Naja naja atra) bite is one of the leading causes of snake-bite mortality in China. The traditional anti-cobra venom serum therapy was found to be expensive and with high frequency of side effects. Therefore attempts were made to generate a high titer immunoglobulin from egg yolk (IgY) of crude cobra-venom immunized Leghorn hens, and to standardize an effective method for producing avian antivenom in relatively pure form. The IgY was isolated first by water dilution method to remove the lipid, then extracted by ammonium sulfate precipitation, and purified through anion exchange chromatogram. The different purities of IgY from different isolating stages were submitted to enzyme-linked immunosorbent assay and SDS-PAGE to determine their titers. Immunoblotting showed that the purified IgY (ion exchange chromatography fraction, IECF) recognized several antigenic fractions of cobra venom, and presented with the character of polyclonal antibody. IECF on SDS-PAGE under reducing conditions migrated as a 65 kDa heavy chain and a 35 kDa light chain, respectively. The LD50 of the N. naja atra venom was 0.62 mg/kg body weight in mice. Four times the LD50 dose of venom was selected as challenge dose, and the ED50 of IgY was 3.04 mg IECF/mg venom. The results indicate that the activity of anti-snake venom IgY could be obviously elevated by ion exchange chromatography, thus possessing therapeutic significance for snakebite envenomation.

Proteomic characterization of the thermostable toxins from Naja naja venom

Naja naja snake venom presents abundant thermostable peptides. Many of them possess useful pharmacological activity that may be employed for drug development. For the proteomic characterization of such toxins, in the present study, Naja naja venom solution was heated up to 100°C for 10, 30, 60, 120, 180 and 300 minutes and protein fractions of non-heated and heated venom were analyzed by two-dimensional nano-liquid chromatography coupled online with tandem mass spectrometry. After heating for 300 minutes, a total of 32 peptides were still detected in the supernatant. The identified peptides belong to the following groups: cardiotoxins, neurotoxins and cytotoxins. It was found that thermostable peptides are able to preserve their analgesic activity after a long heating time in formalin test. Mice injected with 15 µg/g of 60-minute heated venom or with 25 µg/g of 300-minute heated venom revealed even a better analgesic activity than those treated with lidocaine.(AU)

Molecular Cloning and Expression of Cardiotoxin Ⅲ from Naja naja atra in E.coli and Yeast Pichia pastoris / 中国生物工程杂志

Chinese cobra (Naja naja atra) cardiotoxins are three-fingered family with 60～62 amino acids bind by four disulfide bonds. CardiotoxinⅢ (CTXⅢ) is one of the major toxic component which can cause hemolysis and cytotoxicity. However, there is no report on the fusion expression of CTXⅢ in soluble form so far. The cloning, expression and purification of recombinant CTX Ⅲ (rCTXⅢ) from Naja naja atra in E. coli and in yeast Pichia pastoris were reported here. CTXⅢ gene, fused with enterokinase in E.coli His-patch Thioredoxin expression system, were expressed in soluble form and released by osmotic-shock treatment. CTX Ⅲ gene was also cloned and expressed in the methylotropic yeast Pichia pastoris pPIC9K expression vector in the first time. The yield of the secretion level was 9.5 mg/L. Using straightforward one-step chromatography procedure, the rCTXⅢ, with three additional amino acids (GYT) at the N-terminal site, was purified to a purity of more than 90% and recovery yield of 65%. The purified rCTX Ⅲ was further characterized by cytotoxic assay with IC50 4.66μg/ml. An effective expression and purification system for recombinant CTXs in P. pastoris was developed, this system will permit us the ready isolation of active cardiotoxins. This protocol can also be easily used for the production of the toxin in a larger scale with low cost.

Molecular Cloning and Expression of Cardiotoxin Ⅲ from Naja naja atra in E.coli and Yeast Pichia pastoris / 中国生物工程杂志

Chinese cobra (Naja naja atra) cardiotoxins are three-fingered family with 60～62 amino acids bind by four disulfide bonds. CardiotoxinⅢ (CTXⅢ) is one of the major toxic component which can cause hemolysis and cytotoxicity. However, there is no report on the fusion expression of CTXⅢ in soluble form so far. The cloning, expression and purification of recombinant CTX Ⅲ (rCTXⅢ) from Naja naja atra in E. coli and in yeast Pichia pastoris were reported here. CTXⅢ gene, fused with enterokinase in E.coli His-patch Thioredoxin expression system, were expressed in soluble form and released by osmotic-shock treatment. CTX Ⅲ gene was also cloned and expressed in the methylotropic yeast Pichia pastoris pPIC9K expression vector in the first time. The yield of the secretion level was 9.5 mg/L. Using straightforward one-step chromatography procedure, the rCTXⅢ, with three additional amino acids (GYT) at the N-terminal site, was purified to a purity of more than 90% and recovery yield of 65%. The purified rCTX Ⅲ was further characterized by cytotoxic assay with IC50 4.66μg/ml. An effective expression and purification system for recombinant CTXs in P. pastoris was developed, this system will permit us the ready isolation of active cardiotoxins. This protocol can also be easily used for the production of the toxin in a larger scale with low cost.

Molecular Cloning and Expression of Cardiotoxin Ⅲ from Naja naja atra in E.coli and Yeast Pichia pastoris / 中国生物工程杂志

Chinese cobra (Naja naja atra) cardiotoxins are three-fingered family with 60～62 amino acids bind by four disulfide bonds. CardiotoxinⅢ (CTXⅢ) is one of the major toxic component which can cause hemolysis and cytotoxicity. However, there is no report on the fusion expression of CTXⅢ in soluble form so far. The cloning, expression and purification of recombinant CTX Ⅲ (rCTXⅢ) from Naja naja atra in E. coli and in yeast Pichia pastoris were reported here. CTXⅢ gene, fused with enterokinase in E.coli His-patch Thioredoxin expression system, were expressed in soluble form and released by osmotic-shock treatment. CTX Ⅲ gene was also cloned and expressed in the methylotropic yeast Pichia pastoris pPIC9K expression vector in the first time. The yield of the secretion level was 9.5 mg/L. Using straightforward one-step chromatography procedure, the rCTXⅢ, with three additional amino acids (GYT) at the N-terminal site, was purified to a purity of more than 90% and recovery yield of 65%. The purified rCTX Ⅲ was further characterized by cytotoxic assay with IC50 4.66μg/ml. An effective expression and purification system for recombinant CTXs in P. pastoris was developed, this system will permit us the ready isolation of active cardiotoxins. This protocol can also be easily used for the production of the toxin in a larger scale with low cost.

Characterization of an antibacterial peptide from indian cobra (Naja naja) venom

Due to the development of antibiotic resistance in microorganisms, antimicrobial peptides from natural sources have attracted attention in recent times. Several antimicrobial peptides have been isolated from a wide range of animal sources, particularly snake venoms. Naja naja venom showed antibacterial as well as direct and indirect hemolytic activities, and an antibacterial peptide was purified through gel permeation and ion exchange chromatography. Its molecular mass was 2491Da, which was determined using Matrix Assisted Laser Desorption/Ionization-Time-of-Flight (MALDI-TOF) mass spectrometry and the amino acids sequence of the N-terminus was DEQSTHGAYVWKL. The purified peptide showed potent antibacterial activity against Gram-negative and Gram-positive bacterial strains like Escherichia coli, Pseudomonas aeruginosa and Vibrio cholerae, and Staphylococcus aureus, Enterococcus faecalis, Streptococcus pneumoniae, Streptococcus pyogenes, Bacillus subtilis, respectively. The most potent activity was towards Gram-negative bacteria. Activity was retained at concentrations as low as 100µg/ml. Minimum inhibitory concentrations (MIC; in mg) of Naja Antibacterial Peptide (NAP) and known antibiotics against Gram-positive and Gram-negative bacteria were determined using microdilution susceptibility test in sterile 96-well microdilution plates. However, the peptide did not show direct or indirect hemolytic activity.(AU)

Up-regulation of Bax and endonuclease G, and down-modulation of Bcl-X(L) involved in cardiotoxin III-induced apoptosis in K562 cells

Cardiotoxin III (CTX III), a basic polypeptide with 60 amino acid residues isolated from Naja naja atra venom, has been reported to have anticancer activity. CTX III-induced K562 cell apoptosis was confirmed by DNA fragmentation (DNA ladder, sub-G1 formation) and phosphatidylserine (PS) externalization with an IC50 value of 1.7 mug/ml at 48 h. A mechanistic analysis demonstrated that CTX III-induced apoptotic cell death was accompanied by up-regulation of both Bax and endonuclease G (Endo G), and downregulation of Bcl-X(L). CTX III had no effect on the levels of Bcl-2, Bid, XIAP survivin, and AIF proteins. CTX III treatment caused loss of the mitochondrial membrane potential (delta psi m), release of mitochondrial cytochrome c to the cytosol, and activation of both caspase-9 and -3. CTX III-induced apoptosis was significantly blocked by the broad-spectrum caspase inhibitor Z-VAD-FMK. However, CTX III did not generate reactive oxygen species (ROS) and antioxidants, including N-acetylcysteine and catalase, did not block CTX III-induced apoptosis in K562 cells. Modulation of Bax, Bcl-X(L), and the Endo G proteins, release of mitochondrial cytochome c, and activation of caspase-3 and -9 all are involved in the CTX III-triggered apoptotic process in human leukemia K562 cells.

Induction of CTX-d from cobra venoms on NB4 apoptosis and its mechanism / 中草药

Objective To investigate the effects of CTX-d from venoms of cobra (Naja naja atra) on inducing NB4 apoptosis and its mechanism. Methods MTT was used to detect the antitumor effect of CTX-d in vitro; Electron microscope and flow cytometry were used to observe the apoptotic inducing effect of CTX-d in NB4 cells; Mitochondrial transmembrane potential change (??m) was analyzed by flow cytometry; The levels of caspase-9, caspase-3, and cytochrome C in the cytosol fraction were analyzed by Western blotting. Results The IC50 values of CTX-d affected on NB4 cell for 6 and 12 h were 1.8 and 1.35 ?g/mL, respectively. CTX-d could induce morphological changes, such as condensed chromatin and swelling mitochondria in NB4 cells. Analyzed by flow cytometry, CTX-d induced apoptosis in NB4 cells evidenced by increasing sub G1 cell population in a dose- and time-dependent manner. The mitochondrial membrane potential of NB4 cells had already decreased when incubated with CTX-d (1.0 ?g/mL) for 0.5 h, and cytochrome C in the cytosol was detected simultaneously, which indicated the release of cytochrome C from mitochondria to cytosol. The caspase-9 was activated initially at 1 h after 1.0 ?g/mL CTX-d treatment, whereas the cleavage of caspase-3 was detected at 0.5 h. This suggested that some other mechanism may be involved in caspase-3 activation. Conclusion The results suggest that the loss of mitochondrial membrane potential and the release of cytochrome C from the mitochondria into the cytosol are the early events of CTX-d on NB4 apoptosis. Once release into the cytosol, cytochrome C precedes the activation of caspase-9 and -3 to leading to the apoptosis and there are maybe some other mechanism involved in caspase-3 activation.