Local inflammatory reaction induced by Scolopendra viridicornis centipede venom in mice

Bee Venom Induces Acute Inflammation through a H2O2-Mediated System That Utilizes Superoxide Dismutase

Venoms from venomous arthropods, including bees, typically induce an immediate local inflammatory response; however, how venoms acutely elicit inflammatory response and which components induce an inflammatory response remain unknown. Moreover, the presence of superoxide dismutase (SOD3) in venom and its functional link to the acute inflammatory response has not been determined to date. Here, we confirmed that SOD3 in bee venom (bvSOD3) acts as an inducer of H₂O₂ production to promote acute inflammatory responses. In mouse models, exogenous bvSOD3 rapidly induced H₂O₂ overproduction through superoxides that are endogenously produced by melittin and phospholipase A₂, which then upregulated caspase-1 activation and proinflammatory molecule secretion and promoted an acute inflammatory response. We also showed that the relatively severe noxious effect of bvSOD3 elevated a type 2 immune response and bvSOD3 immunization protected against venom-induced inflammation. Our findings provide a novel view of the mechanism underlying bee venom-induced acute inflammation and offer a new approach to therapeutic treatments for bee envenoming and bee venom preparations for venom therapy/immunotherapy.

Recombinant Production and Characterization of a New Toxin from Cryptops iheringi Centipede Venom Revealed by Proteome and Transcriptome Analysis

Among the Chilopoda class of centipede, the Cryptops genus is one of the most associated with envenomation in humans in the metropolitan region of the state of São Paulo. To date, there is no study in the literature about the toxins present in its venom. Thus, in this work, a transcriptomic characterization of the Cryptops iheringi venom gland, as well as a proteomic analysis of its venom, were performed to obtain a toxin profile of this species. These methods indicated that 57.9% of the sequences showed to be putative toxins unknown in public databases; among them, we pointed out a novel putative toxin named Cryptoxin-1. The recombinant form of this new toxin was able to promote edema in mice footpads with massive neutrophils infiltration, linking this toxin to envenomation symptoms observed in accidents with humans. Our findings may elucidate the role of this toxin in the venom, as well as the possibility to explore other proteins found in this work.

Effectiveness of antibiotic prophylaxis in patients with centipede stings: a randomized controlled trial

OBJECTIVE

Centipede stings are a common problem in tropical countries. Current treatment guidelines do not include recommendations for antibiotic prophylaxis to prevent the associated bacterial infection since no previous study has assessed the effectiveness of antibiotic treatment in patients bitten by centipedes. Thus, this study aimed to compare the effectiveness of antibiotic prophylaxis over placebo for the skin infections that occur after a centipede sting.

METHODS

In this randomized, double-blind, multi-center clinical trial conducted in the emergency departments in four hospitals, patients with any history of a centipede sting were prospectively enrolled and divided randomly into two groups. One group received dicloxacillin and the other a placebo. The primary outcome was the incidence of wound infection 3 to 5 days after the centipede sting.

RESULTS

From December 2014 to October 2015, a total of 83 patients were enrolled in the study and were randomized into antibiotic (n=43) and placebo (n=40) groups. Two patients in the antibiotic group developed wound infections, while none showed wound infection in the placebo group (5% vs. 0%). The wound infection rate did not differ significantly between the two groups (P=0.496).

CONCLUSION

Antibiotic prophylaxis may be unnecessary in cases of centipede stings. Proper wound care is an adequate and appropriate treatment for patients with centipede stings. However, the patient should be re-evaluated for detection of secondary bacterial infection.

Mitochondrial activity disruption and local muscle damage induced in mice by Scolopendra polymorpha venom

Background:

Scolopendra polymorpha (S. polymorpha) is a predatory centipede whose venom contains a multiplicity of biochemical effectors that can cause muscle damage and cumulative cell destruction in its prey. Despite previous investigations of S. polymorpha and other centipede venoms, there is a lack of information on the morphological and biochemical patterns elicited by their myotoxic effects. To elucidate these processes, this paper presents evidence of skeletal muscle damage, and alterations in key biochemical mediators that appear only after exposure to centipede venom.

Methods:

Venom was collected and fractionated using RP-HPLC; mouse extensor digitorum longus (EDL) muscle was exposed to whole venom and venom fractions to evaluate myotoxicity by means of creatine kinase (CK) - a muscle damage marker - activity measurements and histochemical analysis.

Results:

CK activity was higher in EDL muscle exposed to venom than in unexposed muscle. This increase was observed after 15 min of venom incubation, and remained stable up to 45 min. Venom-exposed EDL muscle showed signs of muscle damage including necrosis, loss of fascicular structure as well as mitochondrial accumulations and ragged red fibers (RRF), suggesting an impairment in the normal mitochondrial arrangement. Nicotinamide adenine dinucleotide (NADH) and cytochrome oxidase (COX) tests also indicate that respiratory complexes might be affected.

Conclusion:

Our results suggest a different biochemical composition of S. polymorpha venom, based on the different effects of four venom fractions on the cells tested, according to statistical evidence. Fractions F6 and F7 caused the most important alterations.

Complex regional pain syndrome following a centipede bite: a case report

Context: Complex Regional Pain Syndrome (CRPS) is a chronic neuropathic pain condition associated with autonomic features. To date, the development of CRPS following centipede bite has not been reported. We report a case of CRPS likely secondary to a centipede bite.Case details: A 31-year-old female was bitten by a centipede on the right 2nd toe. She was initially treated with analgesics, and two weeks later developed severe pain, allodynia, pruritus, and edema of the right foot, with hyperpigmentation over the affected toe. The X-ray, ultrasound, electromyography, nerve conduction velocity studies of the foot, blood chemistries, and erythrocyte sedimentation rate showed no abnormalities. The patient was diagnosed with CRPS type 1 by fulfilling the Budapest criteria. She was treated with gabapentin, amitriptyline, desloratadine, and fluoxetine, along with physical rehabilitation. Clinical symptoms gradually improved, and resolved at approximately 9 months with persistent hyperpigmentation.Discussion: Centipede bite may be an eliciting event for CRPS. It is unknown whether direct bite trauma or envenomation was the primary etiology in this case. Awareness of this condition is important for early diagnosis and appropriate management.

Experimental Lachesis muta rhombeata envenomation and effects of soursop (Annona muricata) as natural antivenom

Background

In the Atlantic forest of the North and Northeast regions of Brazil, local population often uses the fruit juice and the aqueous extract of leaves of soursop (Annona muricata L.) to treat Lachesis muta rhombeata envenomation. Envenomation is a relevant health issue in these areas, especially due to its severity and because the production and distribution of antivenom is limited in these regions. The aim of the present study was to evaluate the relevance of the use of soursop leaf extract and its juice against envenomation by Lachesis muta rhombeata.

Methods

We evaluated the biochemical, hematological and hemostatic parameters, the blood pressure, the inflammation process and the lethality induced by Lachesis muta rhombeata snake venom. We also assessed the action of the aqueous extract of leaves (AmL) and juice (AmJ) from A. muricata on the animal organism injected with L. m. rhombeata venom (LmrV) in the laboratory environment.

Results

LmrV induced a decrease of total protein, albumin and glucose; and increase of creatine kinase, aspartate aminotransferase, and urea concentrations. It provoked hemoconcentration followed by reduction of hematocrit, an increase in prothrombin time and partial thromboplastin time and a decrease of the blood pressure. LmrV induced the release of interleukin-6, an increase in neutrophils and changes in the serum protein profile, characteristic of the acute inflammatory process. LD₅₀ values were similar for the groups injected with LmrV and treated or untreated with AmJ and AmL. Both treatments play a role on the maintenance of blood glucose, urea and coagulation parameters and exert a protective action against the myotoxicity. However, they seem to worsen the hypotension caused by LmrV.

Conclusion

The treatments with AmJ and AmL present some beneficial actions, but they might intensify some effects of the venom. Therefore, additional studies on A. muricata are necessary to enable its use as natural antivenom for bushmaster snakebite.