New approaches to second-degree burn healing: Polyvinyl alcohol membrane loaded to arnica combined to laser therapy.

Second-degree burns require greater care, as the damage is more extensive and worrisome and the use of a biomaterial can help in the cell repair process, with better planning, low cost, and better accessibility. Arnica has anti-inflammatory and analgesic properties in skin lesions treatments and laser therapy is another therapeutic alternative for burns. Evaluate the effects of arnica incorporated into PVA associated or not with low intensity laser on burns in rats. PVA and PVA with arnica (PVA+A) were obtained and characterized physicochemically. Through in vivo studies, the effects of PVA and PVA+A with or without the application of laser on the lesions allowed histological and immunohistochemical analyzes. PVA+A was biocompatible and with sustained release of the active, being a promising pharmacological tool and confirmed that laser therapy was effective in accelerating the healing process, due to its potential biomodulator, improving inflammatory aspects, promoting rapid healing in skin lesions.

Cordia salicifolia and Lafoensia pacari plant extracts against the local effects of Bothrops jararacussu and Philodryas olfersii snake venoms.

Philodryas olfersii produces similar local effects to Bothrops jararacussu snakebite, which can induce misidentification and bothropic antivenom administration. Antivenom therapy is effective, but has its limitations regarding local damage. Since plants are used in folk medicine to treat snakebite victims, we evaluated the protective properties of Cordia salicifolia and Lafoensia pacari extracts against Philodryas olfersii and Bothrops jararacussu venoms. Preparations pretreated with both extracts inhibited > 90% the B. jararacussu venom-induced neuromuscular blockade, and 52% to 81% the P. olfersii venom-induced blockade. C. salicifolia inhibited the myonecrosis promoted by both venoms; however, L. pacari prevented only the myofilaments hypercontraction. Regarding haemorrhagic activity, C. salicifolia was more effective against B. jararacussu venom, while L. pacari was more effective against P. olfersii venom. On the other hand, for oedema-forming activity the results were the opposite. Considering that both extracts prevented (to different levels) the main manifestations of both snakebites (local symptoms), we endorse further studies involving these plants as coadjuvant in snakebite therapeutics.

Atividade antiofídica de Camellia sinensis contra a ação tóxica de venenos botrópicos em preparação neuromuscular de ave / Antiophidic activity of Camellia sinensis against the toxic action of bothropic venoms in bird neuromuscular preparations

Introdução: venenos de serpentes do gênero Bothrops são capazes de induzir bloqueio neuromuscular em preparações isoladas de mamífero e ave. O tratamento específico é a soroterapia, porém, nem sempre se mostra eficaz contra a toxicidade induzida pelo veneno. Por outro lado, compostos vegetais têm sido estudados com finalidade antiofídica, como é o caso da Camellia sinensis (chá verde). Objetivo: o objetivo foi de avaliar a atividade do extrato alcoólico de Camellia sinensis contra a ação de diferentes venenos botrópicos em preparações neuromusculares de ave. Métodos: foram utilizadas preparações neuromusculares de biventer cervicis de pintainho (BC) que foram incubadas com: venenos de diferentes serpentes do gênero Bothrops (B. jararaca, B. jararacussu, B. alternatus e B. neuwiedi, 50-100 µg/mL), extrato alcoólico de Camellia sinensis (Cs) 100 µg/ml ou pré-tratadas com Cs (30min) seguida da adição dos diferentes venenos botrópicos. Resultados: ao final do experimento, foi observado bloqueio da resposta contrátil em 69,7 ± 4,3% (B. jararaca), 83,1 ± 10% (B. jararacussu), 88,1 ± 4,5% (B. alternatus) e 92,4 ± 5,6% (B. neuwiedi). Quando as preparações foram pré incubadas com o extrato de Cs, as proteções foram de: 62%, 89,2%, 75,1% e 78,2%, respectivamente. Conclusão: conclui-se que o extrato de Camellia sinensis se mostrou eficaz contra a neurotoxicidade induzida por venenos botrópicos

Introduction: venoms from snakes of the Bothrops genus are capable of inducing neuromuscular blockade in preparations isolated from mammals and birds. The specific treatment is serum therapy, but it is not always effective against the toxicity induced by the venom. On the other hand, some plant compounds have been studied for antiophidic purposes, as is the case with Camellia sinensis (green tea). Objective: evaluate the activity of the alcoholic extract from Camellia sinensis against the action of various bothropic venoms in bird neuromuscular preparations. Methods: Chick biventer cervicis (BC) neuromuscular preparations were used which were incubated with venoms from various snakes of the Bothrops genus (B. jararaca, B. jararacussu, B. alternatus and B. neuwiedi, 50-100 µg/ml), Camellia sinensis (Cs) alcoholic extract, 100 µg/ml, or previously treated with Cs (30 min), followed by the addition of the various bothropic venoms. Results: blockade of the contractile response was observed in 69.7 ± 4.3% (B. jararaca), 83.1 ± 10% (B. jararacussu), 88.1 ± 4.5% (B. alternatus) and 92.4 ± 5.6% (B. neuwiedi). When the preparations were previously incubated with Cs extract, results were 62%, 89.2%, 75.1% and 78.2%, respectively. Conclusion: Camellia sinensis extract was found to be effective against neurotoxicity induced by bothropic venoms.

Beneficial effect of crotamine in the treatment of myasthenic rats.

INTRODUCTION: Crotamine is a basic, low-molecular-weight peptide that, at low concentrations, improves neurotransmission in isolated neuromuscular preparations by modulating sodium channels. In this study, we compared the effects of crotamine and neostigmine on neuromuscular transmission in myasthenic rats. METHODS: We used a conventional electromyographic technique in in-situ neuromuscular preparations and a 4-week treadmill program. RESULTS: During the in-situ electromyographic recording, neostigmine (17 µg/kg) caused short-term facilitation, whereas crotamine induced progressive and sustained twitch-tension enhancement during 140 min of recording (50 ± 5%, P < 0.05). On the treadmill evaluation, rats showed significant improvement in exercise tolerance, characterized by a decrease in the number of fatigue episodes after 2 weeks of a single-dose treatment with crotamine. CONCLUSIONS: These results indicate that crotamine is more efficient than neostigmine for enhancing muscular performance in myasthenic rats, possibly by improving the safety factor of neuromuscular transmission.

Protection by Mikania laevigata (guaco) extract against the toxicity of Philodryas olfersii snake venom.

Philodryas olfersii is responsible for most colubrid snakebites in Brazil. In this work, we examined the ability of an ethanolic extract from Mikania laevigata (guaco) leaves to protect against the in vitro neuromuscular activity of P. olfersii venom in mouse phrenic nerve-diaphragm (PND) and chick biventer cervicis (BC) preparations. M. laevigata extract caused moderate twitch-tension facilitation at low concentrations (107.4 ± 6.2% with 20 µl/ml and 118.9 ± 9.3% with 40 µl/ml in PND, and 120.7 ± 7.7% with 40 µl/ml and 114.5 ± 4.4% with 50 µl/ml in BC after 120 min; n = 4-6, mean ± SEM). In PND, the ethanol alone (40 µl/ml, n = 4) did not change the twitch-tension when compared with control. However, in BC, the ethanol produced a higher facilitation when compared to control. At higher concentrations (>50 µl/ml) the extract caused total and reversible blockade in both preparations. Venom (50 µg/ml) caused partial blockade in PND (58.5 ± 12%, n = 4) and almost total blockade in BC (93.5 ± 2.2%, n = 4). Pretreatment of the preparations with extract (40 µl/ml) for 30 min before incubation with venom (50 µg/ml) completely protected PND from neuromuscular blockade and delayed the blockade in BC. The extract alone caused only mild morphological alterations (12.5 ± 0.5% and 10.9 ± 2.3% fiber damage in PND and BC, respectively, compared to 2.3 ± 0.3% and 3 ± 0 in controls; n = 3), with no increase in expression of the inflammatory cytokines TNFα and IFNγ. The ethanol alone also caused slight muscle damage: 4.3 ± 2.4% in PND and 6.7 ± 3.3% in BC (both n = 3) and little or no TNFα and IFNγ expression in both preparations as observed in control. Venom (50 µg/ml) caused 53.5 ± 8.5% and 55.8 ± 4.3% fiber damage in PND and BC, respectively; (n = 3, p < 0.05 vs. controls) and enhanced expression of TNFα and IFNγ. Pretreatment of the preparations with extract protected against venom-induced muscle damage by 80.3 and 60.4 in PND and BC, respectively, and prevented TNFα and IFNγ expression. These results indicate that the M. laevigata extract protected nerve-muscle preparations against the myotoxic, neurotoxic and inflammatory effects of P. olfersii venom.