A oxigenoterapia hiperbárica veterinária integrada ao tratamento da necrose tecidual e osteomielite em cão: relato de caso / Veterinary hyperbaric oxygen therapy integrated to the treatment of tissue necrosis and osteomyelitis in a dog: case report

Na rotina veterinária, as lesões nas extremidades dos membros são constantes e representam um desafio especial pelas características anatômicas, susceptibilidade de exposição óssea e limitações de reparos e reconstruções quando comparado a outras regiões do corpo. A osteomielite, decorrente de mordeduras, tem alta prevalência e sua rápida evolução pode levar a medidas drásticas, como a amputação. Neste trabalho, é relatada a utilização da oxigenoterapia hiperbárica como terapia integrativa ao tratamento convencional e a avaliação de seus efeitos durante as 12 sessões realizadas em uma cadela vítima de mordedura, que apresentava necrose e exposição óssea com colonização por Staphylococcus sp e Pasteurella multocida. A avaliação evolutiva do quadro foi elaborada a partir de registro fotográfico da lesão, com escala, a cada três sessões e submetido à análise morfométrica por software analítico. A velocidade da marcha cicatricial revelou que a utilização desta terapia propiciou precocidade e efetiva atuação na cicatrização e no combate à osteomielite, evitando a amputação do restabelecendo as liberdades da paciente, contribuindo ao aprofundamento do emprego da oxigenoterapia hiperbárica na Medicina Veterinária.(AU)

In the veterinary routine, injuries in the extremities of the limbs are constant and represent a special challenge due to the anatomical characteristics, susceptibility of bone exposure and limitations of repairs and reconstructions when compared to other regions of the body. Osteomyelitis resulting from bites is highly prevalent and its rapid evolution can lead to drastic measures such as amputation. This work describes the use of hyperbaric oxygen therapy as an integrative therapy to conventional treatment and the evaluation of its effects during the 12 treatments performed in a female dog victim of a bite, that presented evolution to necrosis and bone exposure with colonization by Staphylococcus sp e Pasteurella multocida. The evolutionary assessment of the condition was elaborated from a photographic record of the lesion, with scale, every three treatments and submitted to morphometric analysis by analytical software. The speed of the healing gait demonstrated, that the use of this therapy proved precocity and effective action in healing and in the fight against osteomyelitis, avoiding the amputation of the limb, restoring the patient's freedoms. Thus contributing to the deepening on the use of hyperbaric oxygen therapy in veterinary medicine.(AU)

Tratamento de tromboembolismo e preparo para implantação de prótese osteointegrada com oxigenioterapia hiperbárica em uma gata / Treatment of tromboembolism and preparation for an osseointegrated prothesis fixation with hyperbaric oxygen therapy in a kitten

Background: Ischemic neuromyopathy is the most common reason for amputation in cats. In veterinary medicine, the use of prosthetic limbs is not widespread; therefore, in most cases total limb amputation is indicated. However, hyperbaric oxygen therapy (HBOT) is an alternative with several benefits for the treatment of vascular disorders with reperfusion, ischemia, and infection. Therefore, this study aimed to report the positive effects of HBOT on the treatment of ischemic neuromyopathy secondary to arterial thromboembolism on the patient's clinical improvement, and on the preparation of the patient for insertion of an osseointegrated prosthesis. Case: A 6-month-old mixed-breed kitten returned for treatment after undergoing surgery seven days earlier for reduction of traumatic diaphragmatic hernia, during which it suffered a cardiorespiratory arrest. The patient presented with acute pelvic limb paralysis with 24-h evolution, absent femoral pulse, plantar cushions and dorsal part of the limbs cold and pale. After supportive therapy and diagnosis of aortic thromboembolism by arterial Doppler, the patient started adjunctive treatment with HBOT from the first day of hospitalization. Sessions took place in an exclusive hyperbaric chamber for animals and lasted 60 min at a pressure of 2.5 absolute atmospheres and 100% oxygen, initially every 12 h. However, during the first 5 days of hospitalization, the distal region of both pelvic limbs began to show tissue devitalization and edema, and hematologic parameters showed changes on the 7th day. The right pelvic limb (RPL) showed more involvement of superficial tissues, extending to the tarsometatarsal joint region. After 8 days of hospitalization, the devitalized tissue was debrided. The RPL had an extensive devitalized area with exposed bone in the phalanges and necrosis in the pads. The left pelvic limb (LPL) suffered minor complications, with involvement of the phalangeal region. After 12 days, with HBOT every 48 h, exuberant granulation tissue was observed. After 17 days, the patient was discharged, and HBOT sessions were performed weekly. Gangrene of the midfoot and lack of proprioception were observed in RPL, while LPL showed bone divulsion of the 1st, 3rd, and 4th phalanges. Because of the poor prognosis for limb viability, the RPL was partially amputated, and a self-threaded intraosseous prosthesis was inserted. Discussion: The cardiorespiratory arrest that occurred during the surgical procedure to reduce the diaphragmatic hernia without thromboprophylaxis may have contributed to the peripheral ischemia. HBOT was proposed for the adjuvant treatment of ischemic injury because it is especially indicated for cases of ischemia-reperfusion injury. The main hematological parameters were evaluated at an average interval of 7 days. While the platelet count and hematocrit increased, the leukocytosis decreased. This demonstrates the benefit of oxygen therapy in the reported patient. The use of HBOT in orthopedic injuries is known to result mainly in stimulation of osteoblasts, promoting osseointegration of the prosthesis. We conclude that the adjuvant treatment with HBOT helped to preserve a large segment of both pelvic limbs, prevent the progression of necrosis, and provide a healthy bed for fixation of an osseointegrated prosthesis in the RPL, resulting in clinical improvement of the patient.

Necrotic wound caused by jararaca (Bothrops jararaca) in a dog - hyperbaric oxygen therapy (HBTO)

Background: Snakebites are the main responsible for envenoming in dogs and the bothropic venom remains the mostcommon in Brazil, which can induce a necrotic skin wound. Hyperbaric oxygen therapy (HBOT) use 100% oxygen underhigh pressure and used to treat different wounds in human patients. To the authors’ knowledge, no reports regarding to usethe HBOT in skin wound caused by snakebite (Bothrops jararaca) are present in the literature. The present clinical caseaimed to describe the use of HBOT for the treatment of an extensive necrotic wound caused by jararaca snakebite in a dog.Case: A neutered 8-year-old mixed-breed dog, weighing 12 kg, was admitted with a 7-day history of extensive necroticwound was identified in the face and neck causing by a snakebite, and no sign of pain. The procedure of HBOT (singlesessions of 1.5 ATM, 45 min, repeated every 48 h, up to 12 sessions) was decided, and the complete blood cells, alanineaminotransferase, creatinine, creatine kinase, prothrombin time, activated partial thromboplastin time, wound clinicalevaluation were measured at the following time-points: 2nd, 5th, 10th, and 12th sessions. At the 5th session was identifiedleukopenia, neutropenia and lymphopenia. Wound re-epithelialization was initiated after the 5th session, and the completeepithelialization was identified at the 12th session of HBOT. During the HBOT no side effects were identified. Threemonths after the HBOT finished, the animal returned to the clinic and the clinical status evolved positively, and the woundwas completed healed.Discussion: This report described the treatment of an extensive necrotic skin wound caused by snakebite (Bothrops jararaca)in an 8-year-old, neutered, mixed-breed dog using the HBOT. The wound healing...

Necrotic wound caused by jararaca (Bothrops jararaca) in a dog - hyperbaric oxygen therapy (HBTO)

Background: Snakebites are the main responsible for envenoming in dogs and the bothropic venom remains the mostcommon in Brazil, which can induce a necrotic skin wound. Hyperbaric oxygen therapy (HBOT) use 100% oxygen underhigh pressure and used to treat different wounds in human patients. To the authors knowledge, no reports regarding to usethe HBOT in skin wound caused by snakebite (Bothrops jararaca) are present in the literature. The present clinical caseaimed to describe the use of HBOT for the treatment of an extensive necrotic wound caused by jararaca snakebite in a dog.Case: A neutered 8-year-old mixed-breed dog, weighing 12 kg, was admitted with a 7-day history of extensive necroticwound was identified in the face and neck causing by a snakebite, and no sign of pain. The procedure of HBOT (singlesessions of 1.5 ATM, 45 min, repeated every 48 h, up to 12 sessions) was decided, and the complete blood cells, alanineaminotransferase, creatinine, creatine kinase, prothrombin time, activated partial thromboplastin time, wound clinicalevaluation were measured at the following time-points: 2nd, 5th, 10th, and 12th sessions. At the 5th session was identifiedleukopenia, neutropenia and lymphopenia. Wound re-epithelialization was initiated after the 5th session, and the completeepithelialization was identified at the 12th session of HBOT. During the HBOT no side effects were identified. Threemonths after the HBOT finished, the animal returned to the clinic and the clinical status evolved positively, and the woundwas completed healed.Discussion: This report described the treatment of an extensive necrotic skin wound caused by snakebite (Bothrops jararaca)in an 8-year-old, neutered, mixed-breed dog using the HBOT. The wound healing...(AU)

Hyperbaric oxygen therapy in wound healing in mice / [Oxigenoterapia hiperbárica na cicatrização de feridas em camundongos]

We investigated the local and systemic effects of hyperbaric oxygen therapy in BALB/C mice, exposed to two different exposure times, under 2.4 atmosphere (ATM). Fifteen animals were divided into three groups (GI, GII and Control) and underwent a surgical excision of a skin fragment of approximately one square centimeter of the dorsal region. The wounds were treated and monitored for 21 days. In the control group, the wound was cleaned once a day with sterile 0.9% NaCl solution. GI and GII mice were submitted to daily hyperbaric oxygen therapy of 30 or 60minutes sessions, respectively. The wounds were photographed every three days and their surfaces were analyzed by an image analyzer. At 21 days, all animals were euthanatized for histopathological analysis of the skin, lungs and liver in order to identify eventual alterations in wound healing or in the analyzed organs. Animals belonging to GI showed a faster skin wound healing in comparison to the other groups. Animals from GII, however, showed a delayed wound healing process and exhibited lung and microcirculatory alterations. These findings allow us to conclude that the exposure time to the oxygen in hyperbaric environment is crucial and can help or disturb skin wound healing or even be deleterious to other organs.(AU)

Investigaram-se os efeitos locais e sistêmicos da oxigenoterapia hiperbárica em camundongos BALB / C, submetidos a dois tempos de exposição diferentes, sob atmosfera 2,4 (ATM). Quinze animais foram divididos em três grupos (GI, GII e controle) e submetidos à excisão cirúrgica de fragmento de pele de aproximadamente um centímetro quadrado da região dorsal. As feridas foram tratadas e acompanhadas por 21 dias. No grupo controle, a ferida foi limpa uma vez ao dia, com solução estéril de NaCl 0,9%. Camundongos GI e GII foram submetidos à oxigenoterapia hiperbárica diária de 30 ou 60 minutos de sessões, respectivamente. As feridas foram fotografadas a cada três dias, e suas superfícies analisadas por um analisador de imagens. Aos 21 dias, todos os animais foram submetidos à eutanásia para análise histopatológica da pele, do pulmão e do fígado, em busca de eventuais alterações na cicatrização da ferida ou nos órgãos analisados. Animais pertencentes ao GI apresentaram cicatrização mais rápida de feridas cutâneas em comparação aos outros grupos. Já os animais do GII apresentaram retardo na cicatrização da ferida e alterações pulmonares e microcirculatórias. Esses achados permitem concluir que o tempo de exposição ao oxigênio em ambiente hiperbárico é fundamental e pode auxiliar ou atrapalhar a cicatrização de feridas cutâneas ou mesmo ser deletério para outros órgãos.(AU)

Effect of hyperbaric oxygenation on random rat skin flaps vascularization

ABSTRACT Purpose: To evaluate the effect of hyperbaric oxygenation (HBO) on angiogenesis in random rat skin flaps, by immunoexpression of vascular endothelial growth factor A (VEGF-A). Methods: Forty adult rats were divided into four groups: GE) epilated; GE/HBO) epilated subjected to HBO; GER) epilated submitted to dorsal skin flap; GER/HBO) epilated subjected to dorsal skin flap + HBO. HBO was performed with rats inside a chamber under atmosphere close to 100% oxygen and pressure of 2.4 absolute atmospheres, 2h per day during seven consecutive days. GE and GER groups were placed in the hyperbaric chamber without HBO. Then, under anesthesia, skin flaps were removed and separated into three portions relative to pedicle fixation. The samples were fixed in formalin and processed for paraffin embedding. Histological sections were submitted to immunohistochemistry for VEGF-A detection. The number of immunostained-blood vessels were counted under light microscopy. Results: GE and GE/HBO groups showed normal and similar skin morphology in the three flap portions. A fibrin-leukocyte crust, along with denatured collagen and intense leukocyte infiltrate, was mainly observed in the dermis of the medial and distal flap portions of GER group. Meanwhile, the GER/HBO group presented more regions with intact collagen and small areas of leukocyte infiltrate in the three flap regions. VEGF-A-immunostained blood vessels were largely seen in all regions of GE and GE/HBO groups, whereas no significant differences were found between these groups. A decrease in vascularization was noticed in GER and GER/HBO groups, which was more evident in the most distal portion of the flaps. However, the number of VEGF-A-immunostained blood vessels in GER/HBO group was significantly higher when compared to GER group. Conclusions: Hyperbaric oxygenation was associated with increased angiogenesis and improved viability of rat skin flaps.

Effect of preconditioning and postoperative hyperbaric oxygen therapy on colonic anastomosis healing with and without ischemia in rats

Purpose To investigate the effect of hyperbaric oxygen therapy on colonic anastomosis healing with and without ischemia in rats. Methods Forty female rats underwent segmental resection of 1 cm of the left colon followed by end-to-end anastomosis. They were randomly assigned to four groups (n=10 each), a sham group; two groups were submitted to Hyperbaric Oxygen therapy (HBOT) with and without induced ischemia and the induced ischemia group without HBOT. The HBOT protocol evaluated was 100% O2 at 2.4 Atmosphere absolute pressure (ATA) for 60 minutes, two sessions before as a preconditioning protocol and three sessions after the operation. Clinical course and mortality were monitored during all experiment and on the day of euthanasia on the fourth day after laparotomy. Macroscopic appearance of the abdominal cavity were assessed and samples for breaking strength of the anastomosis and histopathological parameters were collected. Results There was no statistically significant difference in mortality or anastomosis leak between the four experimental groups. Anastomosis breaking strength was similar across groups. Conclusion The HBOT protocol tested herein at 2.4 ATA did not affect histopathological and biomechanical parameters of colonic anastomotic healing, neither the clinical outcomes death and anastomosis leak on the fourth day after laparotomy.(AU)

Effect of hyperbaric oxygenation on the expression of glutathione peroxidase 4 and lactoperoxidase genes in the lung of isogenic mice after ischemia/reperfusion injury in the small bowel

Purpose: To evaluate the effect of hyperbaric oxygenation (HBO) on the expression of the genes antioxidant glutathione peroxidase 4 (Gpx4) and lactoperoxidase (Lpo) in the lung of mice subjected to intestinal ischemia and reperfusion (IIR). Methods: Control group (CG) in which were subjected to anesthesia, laparotomy and observation for 120 minutes; an ischemia and reperfusion group (IRG) subjected to anesthesia, laparotomy, small bowel ischemia for 60 minutes and reperfusion for 60 minutes; and three groups treated with HBO during ischemia (HBOG + I), during reperfusion (HBOG + R) and during ischemia and reperfusion (HBOG + IR). Studied 84 genes of oxidative stress by the method (RT-qPCR). Genes with expression levels three times below or above the threshold cycle were considered significantly hypoexpressed or hyperexpressed, respectively (Students t-test p < 0.05). Results: Gpx4 and Lpo were hiperexpressed on IRG, showing a correlation with these genes with lung oxidative stress. Treated with HBO, there was a significant reduction on genic expression on HBOG+I. Conclusion: Hyperbaric oxygenation showed to be associated with decreased expression of these antioxidant genes, suggesting a beneficial effect on the mechanism of pulmonary oxidative stress whenever applied during the ischemia.(AU)

Hyperbaric oxygenation on adhesions prevention after laparotomy in rats

Purpose: To evaluate the effects of hyperbaric oxygenation on prevention of adhesions in the abdominal cavity after laparotomy. Methods: Fifty four rats underwent laparotomy; stitches were made in the four quadrant parietal peritoneum and abdominal cavity closure. Animals were divided into three groups: 1 - control; 2 - subjected to high pressures and oxygenation; 3 - subjected to 100% hyperbaric oxygenation. The animals in groups 2 and 3 were daily submitted to oxygenation hyperbaric chamber after surgery. On the seventh day another laparotomy, registration of procedure, assessment of adhesions and biopsies of the peritoneum were held. Professionals analyzed the videos and the biopsies. Results: Peritoneal cavity adhesions occurred in animals of three groups with no difference between them. In Group 3, the adhesions presented more fragile and vascular proliferation more pronounced, and there was no difference in comparison with the first and second groups. However, there was no significant difference in the evaluation of these parameters between the animals in groups 1 and 2. Conclusions: Postoperative hyperbaric oxygenation in rats submitted to laparotomy did not alter the frequency, but reduced the density of adhesions in the peritoneal cavity and promoted vascular proliferation. The change in atmospheric pressure alone had no influence on the results.(AU)

The protection effect and mechanism of hyperbaric oxygen therapy in rat brain with traumatic injury

Purpose: To investigate the effect of hyperbaric oxygen therapy (HBOT) on traumatic brain injury (TBI) outcome. Methods: The modified Marmarou's weight drop device was used to generate non-lethal moderate TBI rat model, and further developed in vitro astrocytes culturing system. Then, we analyzed the expression changes of interested genes and protein by quantitative PCR and western blot. Results: Multiple HBO treatments significantly reduced the expression of apoptosis promoting genes, such as c-fos, c-jun, Bax and weakened the activation of Caspase-3 in model rats. On the contrary, HBOT alleviated the decrease of anti-apoptosis gene Bcl-2 and promoted the expression of neurotrophic factors (NTFs), such as NGF, BDNF, GDNF and NT-3 in vivo. As a consequent, the neuropathogenesis was remarkably relied with HBOT. Astrocytes from TBI brain or those cultured with 21% O2 density expressed higher NTFs than that of corresponding controls, from sham brain and cultured with 7% O2, respectively. The NTFs expression was the highest in astrocytes form TBI brain and cultured with 21% O2, suggesting a synergistic effect existed between TBI and the following HBO treatment in astrocytes. Conclusion: Our findings provided evidence for the clinical usage of HBO treating brain damages.(AU)

Hyperbaric oxygenation and the genic expression related to oxidative stress in the heart of mice during intestinal ischemia and reperfusion

Purpose: To investigate the effects of hyperbaric oxygenation (HBO) on intestinal ischemia and reperfusion (IR) injury, we evaluated the expression of 84 genes related to oxidative stress and the antioxidant response in mouse hearts. Methods: Four groups were subjected to 60 minutes of intestinal ischemia followed by 60 minutes of reperfusion: IRG, ischemia and reperfusion group without HBO; HBO-IG, which received HBO during ischemia; HBO-RG, which received HBO during reperfusion; and HBO-IRG, which received HBO during ischemia and reperfusion. The control group (CG) underwent anesthesia and laparotomy and was observed for 120 minutes. The (RT-qPCR) method was applied. Genes with expression levels three times below or above the threshold cycle were considered significantly hypoexpressed or hyperexpressed, respectively (Students t-test p<0.05). Results: Eight genes (9.52%) were hyperexpressed in the IRG. When the HBO groups were compared to the IRG, we found a decrease in the expression of eight genes in the HBO-IG, five genes in the HBO-RG, and seven genes in the HBO-IRG. Conclusion: The reduction in the expression of genes related to oxidative stress and antioxidant defense following HBO in mouse hearts resulting from intestinal IR injury was more favorable during the ischemic period than during the reperfusion period.(AU)

Effects of hyperbaric oxygen and nerve growth factor on the long-term neural behavior of neonatal rats with hypoxic ischemic brain damage

Purpose: To evaluate the effects of HBO (Hyperbaric oxygen) and NGF (Nerve growth factor) on the long-term neural behavior of neonatal rats with HIBD (Neonatal hypoxic ischemic brain damage). Methods: The HIBD model was produced by ligating the right common carotid artery of 7 days old SD (Sprague-Dawley) rats followed by 8% O2 + 92% N2 for 2h. Totally 40 rats were randomly divided into 5 groups including sham-operated group, HIBD control group, HBO treated group, NGF treated group and NGF + HBO treated group. The learning and memory ability of these rats was evaluated by Morris water maze at 30 days after birth, and sensory motor function was assessed by experiments of foot error and limb placement at 42 days after birth. Results: The escape latency of HBO treated group, NGF treated group and NGF + HBO treated group was shorter than that of HIBD control group (p 0.01) and longer than that of sham-operated group. The piercing indexes of 3 treated groups were higher than that of HIBD control group (p 0.01). Conclusion: Hyperbaric oxygen and nerve growth factor treatments may improve learning and memory ability and sensory motor function in neonatal rats after hypoxic ischemic brain damage.(AU)

Adjunctive Hyperbaric Oxygen Therapy promotes successful healing in patients with refractory Crohn's disease

PURPOSE: To investigate de adjunctive effect of Hyperbaric Oxygen Therapy in a group of patients with refractory Crohn's disease. METHODS: A total of 29 subjects with refractory Crohn's disease were submitted to daily sessions of Hyperbaric Oxygen Therapy, in a 2800 Sechrist Monoplace Hyperbaric Chamber (Sechrist, USA) pressurized to 2.4 ATA. Each session lasted 2 hours. The endpoint was closure of enterocutaneous fistulas and complete healing of Pyoderma Gangrenosum and perineal Crohn's disease. RESULTS: A total of 829 HBOT sessions were performed and no complications were noted. Overall success rate was 76% (22 cases). Pyoderma Gangrenosum and enterocutaneous fistulas had the highest successful healing rates (100% and 91%, respectively). Perineal Crohn's disease healing rate was 65%. CONCLUSION: Adjunctive Hyperbaric Oxygen Therapy promoted satisfactory healing in a group of patients with refractory Crohn's disease.(AU)

Action of hyperbaric oxygenation in the rat skin flap

PURPOSE: To evaluate the morphology, necrotic area and collagen content in skin flaps of rats subjected to hyperbaric oxygenation (HBO).METHODS:Forty adult rats were divided into four groups: GEC - epilated; GE/HBO - epilated subjected to HBO; GER - epilated submitted to skin flap (2 cm in width /8 cm length in the dorsal area) and GER/HBO - epilated, subjected to skin flap and HBO. HBO (2.4 ATA) was performed for two hours during seven consecutive days. In the eighth day, the rats were anesthetized and the skin flaps were removed and separated into three portions, relative to pedicle fixation. The material fixed in 10% formalin was processed for paraffin embedding; sections were stained by H.E and subjected to picrosirius-red method. The slides examined under light microscopy for evaluation of the collagen content in polarized light microscope and ImageLab(r) software (Bio-Rad).RESULTS:The data showed larger area of necrosis and lower levels of collagen in the three regions of the GER group, whereas in the GER/HBO group the collagen content was similar to the GEC and GE/HBO groups.CONCLUSION: Hyperbaric oxygenation reduced the area of necrosis and preserved the morphology and collagen content in skin flaps of rats.(AU)

Micronucleus test in peripheral blood of rats treated with hyperbaric oxygen after subtotal splenectomy preserving the lower pole

PURPOSE: To assess the mutagenic potential of the oxygen inhalation therapy (HBO), by means of the micronucleus test, performed in peripheral blood of rats that underwent subtotal splenectomy with lower pole preservation (ESTPI), after HBO sessions or simulations.METHODS: Eighteen male Wistar rats, were distributed into three groups of six animals: group 1 - submitted to ESTPI and HBO sessions; group 2 - submitted to ESTPI and HBO simulations; group 3 - underwent cyclophosphamide administration. In groups 1 and 2, blood samples from the animals' tails were collected before surgery (T0) and immediately after the 13th HBO session or simulation (T1). In group 3, tail blood samples were collected from animals before (T0) and 24 hours after (T1) cyclophosphamide (CP) delivery. The number of micronucleated normochromatic erythrocytes (MNNCE) was determined by blind counting 2000 normochromatic erythrocytes (NCE) per animal.RESULTS:Micronuclei average after CP delivery in group 3 was higher than before its use, thus confirming the mutagenic activity of this drug (p=0.01). In groups 1 and 2, no significant difference in the average of Micronuclei was observed when comparing it to blood samples before and after the 13th HBO session or simulation.CONCLUSION: The treatment protocol used in this study did not induce Micronucleus formation in animals submitted to ESTPI and HBO treatment or simulation.(AU)

Effects of hyperbaric oxygen therapy on the liver after injury caused by the hepatic ischemia-reperfusion process

PURPOSE: To evaluate the effects of hyperbaric oxygen on rats submitted to hepatic ischemia and reperfusion. METHODS: Twenty-three Wistar rats were divided at random into 3 groups: SHAM, rats submitted to surgical and anesthetic stress without induction of hepatic ischemia/reperfurion; I/R, rats submitted to total ischemia of the hepatic pedicle for 25 min followed by 5 min of reperfusion; HBOI/R, rats submitted to 60 min of hyperbaric oxygen therapy at a pressure of 2 absolute atmospheres immediately after the experimental protocol of ischemia/reperfusion. Hepatic function was evaluated by quantitation of serum alanine aminotranferase (ALT) and aspartate aminotransferase (AST), and by mitochondrial function through the determination of states 3 and 4 of mitochondrial respiration, respiratory control ratio (RCR) and mitochondrial swelling. Data were analyzed by the Mann-Whitney test, with the level of significance set at p <0.05. RESULTS: There was a significant difference in state 3 values for the SHAM group vs I/R and I/R vs IRHBO, in state 4 values for the SHAM group vs I/R; and in mitochondrial swelling for the SHAM groups vs I/RHBO, SHAM vs I/R, and IR vs I/RHBO. CONCLUSION: The use of hyperbaric oxygen after I/R improved in a relative manner both the production of energy and the effects on the mitochondrial wall.(AU)

Effects of hyperbaric oxygen therapy as hepatic preconditioning in rats submitted to hepatic ischemia/reperfusion injury

To analyze the role of hyperbaric oxygen therapy as hepatic preconditioning in rats submitted to hepatic ischemia and reperfusion. Wistar rats were randomly divided into three groups: SHAM, rats submitted to surgical stress without hepatic ischemia and reperfusion, I/R, rats submitted to total hepatic pedicle ischemia for 30 min, followed by 5 min of reperfusion; HBOI/R, rats submitted to 60 minutes of hyperbaric oxygen therapy at 2 atm and immediately submitted to the experimental protocol of ischemia and reperfusion. Liver function was assessed by measuring serum alanine aminotransferase and aspartate aminotransferase, as well as mitochondrial function by determining states 3 and 4 of mitochondrial respiration, respiratory control rate and mitochondrial permeability transition (mitochondrial swelling). The results were analyzed by the Mann-Whitney test and all P-values <0.05 were considered significant. There were significant differences in serum aspartate aminotransferase values in groups SHAM vs. HBOI/R, I/R vs HBOI/R, alanine aminotranferase in groups SHAM and I/R; State 3 in SHAM groups vs. I/R, SHAM vs. HBOI/R, State 4 in I/R vs HBOI/R groups, respiratory control rate in SHAM vs I/R groups; mitochondrial swelling in SHAM vs. I/R groups, and SHAM vs HBOI/R. Hyperbaric preconditioning improved hepatic mitochondrial function and decreased serum markers of liver injury in the ischemia and reperfusion process.(AU)

Effect of hyperbaric hepatic hyperoxia on the liver of rats submitted to intermittent ischemia/reperfusion injury

PURPOSE: To determine the effect of hyperbaric hyperoxia as hepatic preconditioning on hepatocellular integrity in rats submitted to intermittent hepatic ischemia/reperfusion injury. METHODS: Twenty male Wistar rats were divided into 4 groups (SHAM, I/R, HBO-I/R and CONTROL). The surgical technique consisted of total clamping of the hepatic pedicle for 15 min, followed by reperfusion for 5 min, performed twice. The application of hyperbaric oxygen (HBO) was carried out in a collective chamber (simultaneous exposure of 4 rats) pressurized directly with oxygen at 2 ATA for 60 min. Tissue malondialdehyde (MDA) levels were determined and blood samples were collected for the determination of serum AST and ALT levels. Data were analyzed statistically by the Mann-Whitney test, with the level of significance set at p < 0.05. RESULTS: A statistically significant difference in MDA (p< 0.05) was observed between control and HBO-I/R, but not between control and I/R. Regarding AST, there was a difference between control and I/R and HBO-I/R. Analysis of ALT revealed a significant difference between control and I/R (p<0.05) and between I/R and HBO-I/R, with no difference between control and HBO-IR. CONCLUSION: Hyperoxic preconditioning proved to be favorable regarding alanine transaminase, but not aspartate aminotranserase or malondialdehyde levels.(AU)

Hyperoxic preconditioning in partial liver ischemia

PURPOSE: To evaluate the effect of the hyperbaric oxygen (HBO) treatment as a pre-conditioning for I/R effects in the liver ischemia. METHODS: Fifty-seven male Wistar rats (260-300g) were submitted to the following procedures: SHAM; I/R, rats submitted to I/R, consisting of partial ischemia of 70% of the liver for 90 minutes followed by 15 minutes of reperfusion; HBO I/R 1 ATA, 30 minutes of HBO treatment at the pressure of 1 absolute atmosphere (ATA) during the ischemia time. HBO I/R 2 ATA, 30 minutes of HBO (2 ATA) during the ischemia time. Pre HBO I/R 30', rats submitted to 30 minutes of HBO (2 ATA) immediately before the I/R time. Pre HBO I/R 90', rats submitted to 90 minutes of HBO (2 ATA) immediately before the I/R time. RESULTS: There was a significant worsening of all the parameters of mitochondrial energy production (state 3, 4, RCR and Swelling) in the I/R group, when compared to the Sham group (I/R

Immunoexpression of proliferating cell nuclear antigen (PCNA) in spleen of splenectomized rats with preservation of inferior pole, submitted to hyperbaric oxygenation

PURPOSE: To analyze PCNA immunoexpression on the inferior pole of the spleen of splenectomized rats submitted to hyperbaric oxygenation (HBO). METHODS: Were analyzed fragments of the inferior pole of the spleen of 20 male Wistar rats submitted to splenectomy with preservation of the inferior pole. The rats were divided in two groups: group A (n=10) without HBO and group B (n=10) submitted to HBO at 2, 5 atmospheres per 120 minutes, twice a day for three days and once a day for seven days. The groups were then subdivided in four subgroups: A15 (n=5), with euthanasia on the 15th day; A45 (n=5), with euthanasia on the 45th day; B15 (n=5) with euthanasia on the 15th day and B45 with euthanasia on the 45th day. Respectively on these days, fragments of the inferior pole of the spleen of all animals were collected and analyzed with the immunohistochemistry technique in order to evaluate PCNA expression. RESULTS: There was an expressive increase in PCNA immunoreactivity in the group B. The 45 day postoperative period resulted in a higher level of positivity than the 15 day postoperative period (p<0.01). CONCLUSION: The quantitative analysis of proliferating cell nuclear antigen positive suggests that hyperbaric oxygenation increases cellular proliferation, contributing to splenic regeneration.(AU)