BIOLOGICAL SIGNIFICANCE: Comprehensive venom proteomes of D. russelii from different locales will facilitate better understanding of the geographical variability of the venom in both qualitative and quantitative terms. This is essential to provide scientific basis for the interpretation of differences in the clinical presentation of Russell's viper envenomation. The study revealed a unique venom proteome of the Pakistani D. russelii from the wild (Indus Delta), in which PLA2 predominated (~60% of total venom proteins). The finding unveiled remarkable differences in the venom compositions between the wild (present study) and the captive specimens reported previously. The integration of toxicity tests enabled the correlation of the venom proteome with the envenoming pathophysiology, where the venom showed potent lethality mediated through coagulopathic activity. The Indian VINS Polyvalent Antivenom (VPAV) showed binding activity toward the venom protein antigens; however the immunorecognition of small proteins and PLA2-dominating fractions was low to moderate. Consistently, the antivenom neutralized the toxicity of the wild Pakistani Russell's viper venom at moderate efficacies. Our results suggest that it may be possible to enhance the Indian antivenom potency against the Pakistani viper venom by the inclusion of venoms from a wider geographical range including that from Pakistan into the immunogen formulation.
METHODS: The venoms of DrSL and DrI were decomplexed with C18 high-performance liquid chromatography and SDS-polyacrylamide gel electrophoresis under reducing conditions. The proteins fractionated were identified through nano-ESI-liquid chromatography-tandem mass spectrometry (LCMS/MS). The immunological studies were conducted with enzyme-linked immunosorbent assay. The neutralization of the venom procoagulant effect was evaluated in citrated human plasma. The neutralization of the venom lethality was assessed in vivo in mice adopting the WHO protocol.
RESULTS: DrSL and DrI venom proteomes showed comparable major protein families, with phospholipases A2 (PLA2) being the most abundant (> 60% of total venom proteins) and diverse (six protein forms identified). Both venoms were highly procoagulant and lethal (intravenous median lethal dose in mice, LD50 = 0.24 and 0.32 µg/g, for DrSL and DrI, respectively), while lacking hemorrhagic and anticoagulant activities. VPAV was immunoreactive toward DrSL and DrI venoms, indicating conserved protein antigenicity in the venoms. The high molecular weight venom proteins were, however, more effectively immunorecognized than small ones. VPAV was able to neutralize the coagulopathic and lethal effects of the venoms moderately.
CONCLUSION: Considering that a large amount of venom can be injected by Russell's viper during envenomation, the potency of antivenom can be further improved for optimal neutralization and effective treatment. Region-specific venoms and key toxins may be incorporated into the immunization procedure during antivenom production.
AIMS OF THE STUDY: The present study aims to establish safety profile for the consumption of cultivated fruiting body of O. sinensis (FBOS) by 28-days sub-acute toxicity study in Sprague Dawley rats.
MATERIALS AND METHODS: Rats were orally administered with cultivated FBOS at three graded doses (250, 500 and 1000mg/kg), once daily for 28 consecutive days. Control group received distilled water. General observations (gross behavioral changes and toxic symptoms) and body weight of each animal were monitored daily. Haematological, serum biochemical and histopathological analysis were carried out at the end of the experiment (Day 29).
RESULTS: No behavioral changes, toxic symptoms or death was observed in rats throughout the dosing period. Cultivated FBOS treatment up to 1000mg/kg did not cause any adverse effect on the growth of the animals. Results from haematology and serum biochemistry revealed no toxic effect following cultivated FBOS treatment at three graded doses for 28 days. In addition, no treatment related histopathological changes were noted in heart, spleen, kidney, lung and liver of the animals.
CONCLUSION: The present study revealed that oral administration of cultivated FBOS for 28 days, at dosage up to 1000mg/kg did not pose toxicological concern in rats. Therefore, the no-observed-adverse-effect level (NOAEL) dose of cultivated FBOS in 28-days subacute toxicity study is higher than 1000mg/kg.
Methods: The cytotoxicity of the Ligno TG-K against human breast (MCF7), prostate (PC3) and lung (A549) adenocarcinoma cell lines was evaluated using MTT cytotoxicity assay. The cytotoxic mechanisms of the active high molecular weight proteins (HMWp) fraction were investigated through detection of caspases activity and apoptotic-related proteins expression by Western blotting. The in vivo antitumor activity of the isolated HMWp was examined using MCF7 mouse xenograft model. Shotgun LC-MS/MS analysis was performed to identify the proteins in the HMWp.
Results and Discussion: Cold water extract of the sclerotia inhibited proliferation of MCF7, A549 and PC3 cells with IC50 ranged from 28.9 to 95.0 µg/mL. Bioassay guided fractionation of the extract revealed that HMWp exhibited selective cytotoxicity against MCF7 cells via induction of cellular apoptosis by the activation of extrinsic and intrinsic signaling pathways. HMWp activated expression of caspase-8 and -9 enzymes, and pro-apoptotic Bax protein whilst inhibiting expression of tumor survivor protein, Bcl-2. HMWp induced tumor-cell apoptosis and suppressed growth of tumor in MCF-7 xenograft mice. Lectins, serine proteases, RNase Gf29 and a 230NA deoxyribonuclease are the major cytotoxic proteins that accounted for 55.93% of the HMWp.
Conclusion: The findings from this study provided scientific evidences to support the traditional use of the L. tigris sclerotia for treatment of breast cancer. Several cytotoxic proteins with high abundance have been identified in the HMWp of the sclerotial extract and these proteins have potential to be developed into new anticancer agents or as adjunct cancer therapy.