Cryotherapy: biochemical alterations involved in reduction of damage induced by exhaustive exercise

When exercises are done in intense or exhaustive modes, several acute biochemical mechanisms are triggered. The use of cryotherapy as cold-water immersion is largely used to accelerate the process of muscular recovery based on its anti-inflammatory and analgesic properties. The present study aimed to study the biochemical effects of cold-water immersion treatment in mice submitted to exercise-induced exhaustion. Swiss albino mice were divided into 4 treatment groups: control, cold-water immersion (CWI), swimming exhaustive protocol (SEP), and SEP+CWI. Treatment groups were subdivided into times of analysis: 0, 1, 3, and 5 days. Exhaustion groups were submitted to one SEP session, and the CWI groups submitted to one immersion session (12 min at 12°C) every 24 h. Reactive species production, inflammatory, cell viability, and antioxidant status were assessed. The SEP+CWI group showed a decrease in inflammatory damage biomarkers, and reactive species production, and presented increased cell viability compared to the SEP group. Furthermore, CWI increased acetylcholinesterase activity in the first two sessions. The present study showed that CWI was an effective treatment after exercise-induced muscle damage. It enhanced anti-inflammatory response, decreased reactive species production, increased cell viability, and promoted redox balance, which could decrease the time for the recovery process.

Endotoxemia por lipopolissacarídeo de Escherichia coli, em eqüinos: efeitos de antiinflamatórios nas concentrações sérica e peritoneal do fator de necrose tumoral alfa (TNF-alfa) / Escherichia coli lipopolisacharide (LPS) induced endotoxemia in horses: effects of anti-inflammatory drugs on seric and peritoneal tumor necrosis factor alpha (TNF-alpha) concentrations

Avaliou-se a inibição da produção do fator de necrose tumoral alfa (TNF-alfa) devido ao pré-tratamento com antiinflamatório esteroidal (dexametasona) e não esteroidal (diclofenaco sódico) em eqüinos com endotoxemia induzida experimentalmente. Foram utilizados 15 cavalos machos não castrados, distribuídos em três grupos de cinco animais: controle (C), diclofenaco sódico (DS) e dexametasona (DM). A endotoxemia subletal foi induzida pela infusão intravenosa (IV) de 0,1mg/kg/pv de lipopolissacarídeo (LPS) de Escherichia coli 055:B5, administrado em 250ml de solução estéril de cloreto de sódio a 0,9 por cento, durante 15min. Os cavalos do grupo-controle foram tratados com solução de cloreto de sódio a 9 por cento IV. Nos animais do grupo DS, administraram-se, por via oral, 2,2mg/kg de diclofenaco sódico e, nos do grupo DM, 1,1mg/kg de dexametasona IV, respectivamente, 60 e 30min antes da infusão da endotoxina. Mensurou-se, por meio de ensaio de toxicidade com células da linhagem L929, a concentração de TNF-alfa no soro e no líquido peritoneal às 0, 1», 3 e 6 horas após injeção do LPS. No grupo-controle, observou-se aumento significativo de TNF-alfa sérico, em relação ao valor basal e aos grupos DS e DM, 1,15 horas após a indução da endotoxemia. No líquido peritoneal, as concentrações observadas estavam abaixo daquelas da curva padrão de TNF-alfa, não havendo diferença entre os grupos (P>0,05)

The inhibition of tumor necrosis factor alpha (TNF-alpha) production due to pre-treatment with steroidal (dexamethazone) and non-steroidal (sodium diclofenac) anti-inflammatories was studied in horses under experimentally induced endotoxemy. Fifteen stallions were allotted into three groups of five animals each: control (C), sodium diclofenac (SD) and dexamethazone (DM). Sublethal endotoxemy was induced with 0.1mg/kg/bw Escherichia coli 055:B5 lipopolysaccharide (LPS), IV, administrated in 250ml of 0.9 percent sterile sodium chloride, during 15 minutes. Control group horses received 9 percent sodium chloride, IV. SD group animals were orally administrated 2.2mg/kg sodium diclofenac and DM horses received 1.1mg/kg dexamethazone, IV, 30 and 60 minutes before endotoxin infusion, respectively. TNF-alpha concentration was measured in serum and peritoneal fluid by toxicity assay using L929 lineage cells at 0, 1», 3 and 6 hours after LPS injection. Ninety minutes after endotoxemy induction, it was verified a significant increase of serum TNF-a concentration in horses from control group in relation to the basal values as well as results of horses from SD and DM groups. In peritoneal fluid, the measured concentrations were lower than those from TNF-a standard curve and difference among the groups was not verified (P>0.05)

Effects of diclofenac and dexamethasone on horse experimental endotoxemia

Fifteen healthy Mangalarga horses, aged two to three years were used to evaluate the possible beneficial effects of dexamethasone and sodium diclofenac administration during experimental endotoxemia in horses. They were divided into three groups with five animals each: control (C), sodium diclofenac (SD) and dexamethasone (DM). All groups were given 0.1æg of Escherichia coli O55:B5 endotoxin/kg of body weight, intravenous, over 15 minutes, and one of the following preparations: group C - 20ml of 0.9 percent saline intravenous, 30 minutes before endoxin infusion; group SD - 2.2mg/kg, per os, 60 minutes before endotoxin infusion and group DM - 1.1 mg/kg, intravenous, 30 minutes before endotoxin infusion. No increase in rectal temperature was observed in the SD or DM treated groups. SD did not prevent the significant leukopenia, neutropenia and lymphopenia induced three hours after LPS injection, but DM attenuated these changes. No significant changes in plasma and peritoneal fluid total protein, inorganic phosphorus or glucose concentrations and in total nucleated cell count in peritoneal fluid were observed. SD was effective to prevent the fever and changes in intestinal borborygmi and DM blocked the cellular changes induced by experimental endotoxemia.

Differences in the acquired resistance of dogs, hamsters, and guinea pigs to repeated infestations with adult ticks Rhipicephalus sanguineus (Acari: Ixodidae)

Grupos experimentais de cäes, hamsters e cobaias sem contato anterior com carrapatos, sofreram três infestaçöes consecutivas por carrapatos Rhipicephalus sanguineus adultos e a resistência adquirida comparada com base na variaçäo de alguns dos parâmetros biológicos da fêmea do carrapato. Os resultados mostraram que hamsters e cobaias principalmente, desenvolvem uma reaçäo imune muito eficiente a esta espécie de carrapato como demonstrado por uma queda altamente significativa na taxa de eficiência da fêmea em converter sua reserva alimentar em ovos e larvas da primeira para as segunda e terceira infestaçöes. Já cäes foram incapazes de desenvolver tal resistência. Neste hospedeiro a performance das fêmeas dos carrapatos foi similar durante todas as infestaçöes, havendo até uma tendência de melhora com a sucessäo das infestaçöes. Estes resultados reforçam a necessidade de estudos comparativos sobre a resistência adquirida a carrapatos, envolvendo hospedeiros naturais e näo naturais, como forma de colocar em evidência mecanismos de defesa que possam estar alterados ou ocultos em relaçöes parasita-hospedeiro naturais