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)

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)

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)

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)

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)

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)

EFEITOS DA INTERAÇÃO ENTRE TEMPERATURA E OXIGÊNIO DISSOLVIDO EM JUVENIS DE PACU Piaractus mesopotamicus (HOLMBERG 1887)

O pacu P. mesopotamicus é uma espécie que pelas suas características, apresenta grande potencial para cultivos intensivos, nos quais o oxigênio dissolvido (OD) é um dos principais limitantes. Além disso, o cultivo dessa espécie em regiões de clima subtropical, onde ocorre ampla variação térmica, a interação de fatores como o OD e a temperatura podem causar alterações bioquímicas e fisiológicas nos peixes. Dessa forma, o objetivo deste estudo foi verificar os efeitos da interação entre diferentes temperaturas e níveis de OD nos parâmetros hematológicos e de estresse oxidativo em juvenis de pacu. Foram realizados 2 experimentos (EXP): EXP 1 - interação entre diferentes temperaturas (~18, ~23 e ~28 °C) e níveis de OD (~2 - hipóxia, ~4,5 hipóxia moderada e ~7 mg OD L-1 normóxia) por um período de 12 h. Imediatamente após esse período foram coletadas amostras de sangue, brânquias, fígado, músculo e cérebro de 9 peixes por tratamento. No EXP 2 os peixes foram expostos a interação entre as mesmas temperaturas supracitadas, hipóxia e normóxia (~2 e ~7 mg OD L-1) durante 12 h. Ao final desse período foram submetidos a diferentes velocidades de reoxigenação, abrupta (0,5 h) e gradual (5 h). Após 1, 3 e 12 h do final da reoxigenação foram coletadas amostras de sangue (n=9), e em 1 e 12 h também amostras de brânquias e fígado. Os resultados demonstram que os efeitos da interação entre diferentes temperaturas e níveis de OD em juvenis de pacu são órgão específicos. A análise dos parâmetros sanguíneos durante a exposição a diferentes temperaturas e níveis de hipóxia indicaram alterações mais evidentes na glicose e pH sanguíneos. A reoxigenação abrupta a 23 e 28 ºC levou a alterações na glicose sanguínea e na maior temperatura no lactato sanguíneo em até 3 h. Entretanto, na temperatura de 23 ºC o aumento do lactato sanguíneo ocorreu após 3h e se manteve elevado até 12 h após o fim da reoxigenação.Uma indução da condição pró oxidante foi observada no fígado, músculo e cérebro ix impulsionado pela interação de diferentes temperaturas e níveis de hipóxia 1 evidenciado pelo aumento nos níveis de dano oxidativo (lipoperoxidação - LPO e conteúdo de tióis proteicos - PSH) associados a uma inibição do sistema de defesa antioxidante (capacidade antioxidante total - ACAP e glutationa-S-transferase - GST). Com relação às velocidades de reoxigenação, juvenis de pacu mantidos em 18 °C foram capazes de se adaptar melhor com uma reoxigenação abrupta, evidenciada pelos menores níveis de dano oxidativo (LPO) nas brânquias e no fígado. Após 12 h do final da reoxigenação apenas os peixes mantidos em 23 °C e submetidos a reoxigenação abrupta e aqueles mantidos em 28 °C e submetidos a reoxigenação gradual apresentaram todos os parâmetros sanguíneos dentro dos níveis basais. Sendo assim, a interação entre diferentes temperaturas e níveis de OD por um período de 12 h causam distúrbios metabólicos, ácido base, além de induzir estresse oxidativo. Entretanto, essa espécie demonstrou ser tolerante à hipóxia e à reoxigenação, apresentando 100% de sobrevivência. Peixes mantidos entre 23 e 28 °C e submetidos à reoxigenação gradual são menos susceptíveis a danos oxidativos. Um período de 12 h é suficiente para restabelecer os parâmetros bioquímicos e fisiológicos dependendo da temperatura e velocidade de reoxigenação que foram submetidos os pacus.

The pacu, P. mesopotamicus, is a species that, due to its characteristics, has great potential for intensive culture, in which dissolved oxygen (DO) is one of the main limitations. In addition, the culture of this species in regions of subtropical climate, where there is wide thermal variation, the interaction of factors such as DO and temperature can cause biochemical and physiological changes in fish. Thus, the aim of this study was to verify the effects of interaction between different temperatures and DO levels on hematological parameters and oxidative stress in pacu juveniles. Two experiments were carried out (EXP): EXP 1 - interaction between different temperatures (~ 18, ~ 23 and ~ 28 ° C) and DO levels (~ 2 - hypoxia, ~ 4.5 - moderate hypoxia and ~ 7 mg DO L-1 normoxia) for a period of 12 h. Immediately after this period, blood, gills, liver, muscle and brain samples were collected from 9 fish per treatment. In EXP 2 the fish were exposed to interaction between the same temperatures mentioned above, hypoxia and normoxia (~ 2 and ~ 7 mg OD L-1) for 12h. At the end of this period, they were submitted to different speeds of reoxygenation: abrupt (0.5 h) and gradual (5 h). After 1, 3 and 12 h of the end of reoxygenation blood samples were collected (n=9), as well as samples of gills and liver at 1 and 12 h. The results demonstrate that the effects of the interaction between different temperatures and DO levels in pacu juveniles are organ specific. The analysis of blood parameters during exposure to different temperatures and levels of hypoxia indicated more evident changes in blood glucose and pH. The abrupt reoxygenation at 23 and 28 ºC provoked changes in blood glucose and at the highest temperature in blood lactate in up to 3 hours. However, at 23 ºC, the blood lactate increase occurred after 3 h and remained elevated until 12 hours after the end of reoxygenation. An induction of pro oxidant condition was observed in the liver, muscle and brain driven by the interaction of different temperatures and hypoxia levels,xi evidenced by increase in oxidative damage levels (lipoperoxidation 1 - LPO and protein thiol content - PSH) associated with an inhibition of antioxidant defense system (total antioxidant capacity - ACAP and glutathione-S-transferase - GST). Regarding reoxygenation speeds, pacu juveniles kept at 18 °C were able to adapt better with abrupt reoxygenation, evidenced by the lower oxidative damage levels (LPO) in the gills and liver. After 12 h from the end of reoxygenation, only fish kept at 23 °C and subjected to abrupt reoxygenation and those kept at 28 °C and subjected to gradual reoxygenation showed all blood parameters within baseline levels. Thus, the interaction between different temperatures and DO levels for a period of 12 h causes metabolic and acid base disturbances, in addition to inducing oxidative stress. However, this species proved to be tolerant to hypoxia and reoxygenation. Fish kept between 23 and 28 °C and subjected to gradual reoxygenation are less susceptible to oxidative damage, present 100% survival. A period of 12 h is sufficient to reestablish the biochemical and physiological parameters depending on the temperature and speed of reoxygenation that were submitted the pacu.

Avaliação da manobra de recrutamento alveolar por escalonamento da PEEP por meio da técnica de tomografia computadorizada em cães submetidos à anestesia intravenosa total

A atelectasia pulmonar é um evento comum que ocorre durante a anestesia. A ventilação mecânica (VM) é indicada nestes casos para reverter o quadro garantindo trocas gasosas adequadas e melhora da oxigenação. Apenas a instituição da VM não é suficiente para realizar a abertura destes alvéolos, sendo necessário a associação de manobras de recrutamento alveolar (MRA). As MRA não são isentas de riscos e podem promover hipersdistensão de algumas áreas do pulmão, com intuito de visualizar tais alterações e minimizá-las, técnicas de imagens são utilizadas, como a tomografia computadorizada. Este estudo avaliou a MRA por escalonamento de PEEP, oxigenação e troca gasosa de 12 cães jovens, pesando acima de 15 kg, com idade entre 1 a 5 anos, de ambos os sexos e de diferentes raças, submetidos a castração eletiva. Para tanto foram avaliados parâmetros cardiovasculares, de oxigenação, aeração pulmonar, mecânica ventilatória e imagens de tomografia computadorizada (TC). Os animais receberam acepromazina (0,03 mg/kg) e meperidina (3 mg/kg) por via IM como medicação pré-anestésica. A indução anestésica foi realizada com propofol (5 mg/kg) e mantida com a infusão do mesmo (0,2 0,4 mg/kg/min) associado ao remifentanil (0,1 a 0,4 mcg/kg/min) e rocurônio (bolus 0,6 mg/kg, seguido de infusão contínua 1 mg/kg/h). Inicialmente os animais foram ventilados no modo volume controlado de 7 mL/kg, PEEP 0 cmH2O e FiO2 de 100% durante os primeiros 30 min de anestesia. Em seguida, iniciou-se a MRA por escalonamento da PEEP (5, 10, 15, 20 cmH2O ascendente e 15, 10, 5 cmH2O descendente), em todos os momentos se fez a aquisição das imagens de tomografia computadorizada (TC), como também dos demais parâmetros. Foi possível observar melhora na complacência estática (Cstat) e no shunt pulmonar ao fim da MRA. A TC foi capaz de demonstrar que a MRA melhorou a aeração em todo o pulmão, inclusive nas regioes dependentes (centro-dorsal e dorsal). Foi observado aumento do volume de gás e redução da atenuação com o aumento da PEEP e redução do volume e aumento da atenuação com sua diminuição. Contudo ao chegar em PEEP 5d cmH2O, o volume foi significativamente maior que em PEEP 0 cmH2O e a atenuação menor. Portanto a TC permitiu adequada avaliação da MRA a partir de dados de volume e atenuação pulmonar nas imagens e ainda evidenciando ausência de hiperaeração pulmonar ao longo da mesma.

Pulmonary atelectasis is a common event that occurs during anesthesia. Mechanical ventilation (MV) is indicated to reverse this condition, ensuring adequate gas exchange and improved oxygenation. However, simply instituting MV is not sufficient to open the alveoli, as it requires the combination with alveolar recruitment maneuvers (ARM). ARMs are not exempt from risks and can lead to overdistension of some areas of the lung. In order to visualize such alterations and minimize them, imaging techniques can be used, such as computed tomography. The present study evaluated a PEEP titration ARM, oxygenation and gas exchange in 12 young dogs, weighing over 15 kg, aged between 1 and 5 years olds, of both sexes and various breeds, submitted to elective ovariohysterectomy or orchiectomy. Therefore, cardiovascular parameters, oxygenation, pulmonary aeration, ventilatory mechanics and computed tomography (CT) images were evaluated. The animals received acepromazine (0.03 mg/kg) and meperidine (3 mg/kg) intramuscularly as premedication. Anesthesia was induced with propofol (5 mg/kg) and maintained with constant rate infusions of propofol (0.2 - 0.4 mg / kg / min), remifentanil (0.1 to 0.4 mcg / kg / min ) and rocuronium (bolus of 0.6 mg / kg, followed by 1 mg / kg / h). Initially, the animals underwent volume-controlled ventilation with tidal volume of 7 mL / kg, PEEP 0 cmH2O and 100% FiO2 for 30 minutes. Afterwards, the ARM was performed with PEEP titration (sequentially ascending PEEP of 5, 10, 15 and 20 cmH2O, and then descending from 20 to 15, 10 and 5 cmH2O). In all these times points, CT images were acquired, as were the other parameters. An improvement in static compliance (Cstat) and pulmonary shunts was observed by the end of the ARM. CT demonstrated that the ARM enhanced aeration throughout the lungs, including the dependent areas (central-dorsal and dorsal). An increase in gas volume and a decrease in attenuation was observed with PEEP increase, likewise gas volume reduced and attenuation augmented with PEEP decrease. However, when PEEP 5d (descending) cmH2O was reached, gas volume was significantly greater than that it was with PEEP 0 cmH2O, and the attenuation was lower. Therefore, CT allowed an adequate assessment of ARM based on pulmonary volume and attenuation data, and also evidenced the absence of pulmonary hypereraeration throughout the maneuver.

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

Hyperbaric oxygen therapy and ischemia and reperfusion: a valuable association to attenuate ischemic lesion and hepatic reperfusion

PURPOSE: To investigate the consequences of the association between hyperbaric oxygen therapy and hepatic ischemia / reperfusion. METHODS: Wistar rats were divided into three groups: SHAM, rats submitted to surgical stress and anesthetic but not hepatic ischemia or reperfusion, I / R, rats submitted to total hepatic pedicle ischemia for 30 min, followed by 5 min of reperfusion; HBO120, rats submitted to 120 min of hyperbaric oxygen therapy at two absolute atmospheres and immediately after submitted to the experimental protocol of ischemia and reperfusion. The preservation of the hepatic function was evaluated by determining mitochondrial swelling and malondialdehyde tissue level, as well as alanine aminotransferase and aspartate aminotranferase serum levels. The results were analyzed using the Mann-Whitney test and differences were considered significant for p<0.05. RESULTS: There were significant differences in values: mitochondrial swelling of the I / R group compared to SHAM and HBO120; malondialdehyde between SHAM vs. I / R, SHAM vs HBO120, and I / R vs HBO120, alanine aminotransferase between SHAM vs. I / R . There was no significant difference between groups in aspartate aminotransferase serum levels. CONCLUSION: The association between hyperbaric oxygen therapy and hepatic ischemia and reperfusion process was positive.(AU)

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)

INTERFERÊNCIA DA HIPOXEMIA NA AVALIAÇÃO DO NÍVEL DE CONSCIÊNCIA PELO ÍNDICE BISPECTRAL EM CAVALOS ANESTESIADOS COM PROPOFOL OU ISOFLUORANO

O índice bispectral (BIS) é um parâmetro derivado do eletroencefalograma que permite a monitoração da profundidade anestésica de forma quantitativa. Embora sua utilização seja ampla na medicina, seu uso é limitado na medicina veterinária, havendo diferentes resultados quanto a sua aplicabilidade, inclusive em cavalos. A hipoxemia não é uma complicação incomum na anestesia equina, podendo levar a alterações do BIS de forma que este não reflita corretamente o componente hipnótico da anestesia. Este estudo teve como objetivos comparar o índice bispectral e a avaliação clínica da profundidade anestésica em cavalos anestesiados com isofluorano ou propofol e avaliar a influência da hipoxemia nos valores do BIS em cavalos submetidos a hipoxemia por ventilação monopulmonar. Foram utilizados seis animais submetidos a anestesia para toracoscopia. Após pré-medicação com xilazina e indução anestésica com propofol e guaiafenesina, a anestesia foi mantida com propofol (PRO) ou isofluorano (ISO) sendo a taxa de infusão e a fração expirada dos anestésicos alteradas segundo avaliação clínica da profundidade anestésica. O BIS foi avaliado nos animais acordados, após 10 minutos de sedação, a cada 10 minutos durante a manutenção da anestesia, no início do despertar e no momento da extubação. Foram avaliados parâmetros cardiovasculares e respiratórios, variáveis hemodinâmicas e de oxigenação tecidual durante a anestesia. Os valores médios de BIS foram 97±1 para animais acordados e 80±6 para animais sedados, havendo diferença significativa entre estes e entre os animais anestesiados (p<0,05). Para os planos superficial, adequado e profundo de anestesia o BIS foi 68±1, 67±10 e 59±7, respectivamente, sendo o BIS no plano profundo significativamente menor quando comparado ao plano superficial (p=0,014) No inicio do despertar o BIS foi de 79±8 e de 87±6 no momento da extubação, valor significativamente mais alto quando comparado aos animais anestesiados. A hipoxemia levou a aumento significativo nos valores de BIS de 59±6 para 65±7 (p=0,012), acompanhado de aumento na FC, PAM e EMG no PRO. O BIS pode ser utilizado para diferenciar planos mais profundos de anestesia em cavalos, em especial quando anestesiados com isofluorano, e na percepção do despertar em cavalos anestesiados com propofol ou isofluorano. A hipoxemia ocasionar o aumento nos valores de BIS decorrente da ativação simpática e aumento da EMG em cavalos anestesiados com propofol.

Bispectral index (BIS) is an electroencephalogram derivated parameter which allows depth of anesthesia monitoring in an objective way. Althought it has a widespread use in medicine, its use in veterinary medicine is limitated, with different results regarding its applicability, including horses. Hypoxemia is not an uncommon complication during equine anesthesia and may lead to BIS changes so that it does not accurately reflect the hypnotic component of anesthesia. The objectives of this study were to compare the bispectral index and clinical evaluation of anesthetic depth in horses anesthetized with isoflurane or propofol; and to evaluate the influence of hypoxemia on BIS values in horses submitted to hypoxemia by monopulmonary ventilation. It were used six horses undergoing anesthesia for thoracoscopy. After premedication with xylazine and anesthetic induction with propofol and guaiafenesin, anesthesia was maintained with propofol (PRO) or isoflurane (ISO) and the infusion rate and the expired fraction of the anesthetics were altered according to clinical evaluation of anesthetic depth. The BIS was evaluated in the awake animals, 10 minutes after sedation, every 10 minutes during anesthesia maintenance, at the beginning of the awakening and at the time of extubation. Cardiovascular and respiratory parameters, hemodynamic variables and tissue oxygenation were evaluated during anesthesia. The mean values of BIS were 97 ± 1 for awake animals and 80 ± 6 for sedated animals, with a significant difference between these and between anesthetized animals (p <0.05). For the superficial, adequate and deep planes of anesthesia the BIS was 68 ± 1, 67 ± 10 and 59 ± 7, respectively, and the BIS in the deep plane was significantly smaller when compared to the superficial plane (p= 0.014). BIS was 79 ± 8 and 87 ± 6 at the time of extubation, a significantly higher value when compared to anesthetized animals. Hypoxemia led to a significant increase in BIS values from 59 ± 6 to 65 ± 7 (p =0.012), accompanied by an increase in HR, MAP and EMG in the PRO. BIS can be used to differentiate deeper planes of anesthesia in horses, especially when anesthetized with isoflurane, and in the perception of awakening in horses anesthetized with propofol or isoflurane. Hypoxemia may lead to increased BIS values due to sympathetic activation and increased EMG in horses anesthetized with propofol.

Combination hyperbaric oxygen and temozolomide therapy in c6 rat glioma model / Terapia combinada de oxigênio hiperbárico e temozomida no modelo C6 de glioma em ratos

PURPOSE: Temozolomide (TMZ) has anti-tumor activity in patients with malignant glioma. Hyperbaric oxygen (HBO) may enhance the efficacy of certain therapies that are limited because of the hypoxic tumor microenvironment. We examined the combined effects of TMZ-HBO in a rat glioma model. METHODS: After stereotactic injection of C6/LacZ rat glioma cells into the Wistar rats brain, the rats were randomly assigned to three treatment groups [group 1, control treatment; group 2, TMZ alone; group 3, a combination of TMZ and HBO]. Rats were sacrificed 18 days after treatment, and number of intra-/peri-tumoral vessels, microendothelial proliferations, immunohistochemistry and necrotic area were evaluated. RESULTS: Tumoral tissue was stained only sparsely with GFAP. Temozolomide treatment was significantly decreased in tumor tissue intratumoral vessel number / total tumor area level. The level of Ki67 was significantly decreased in the tumor tissue of the group 3. Additionally, the total necrotic area / total tumor volume (%) was decreased significantly in tumor tissue of the group 3 rats compared to group1 and 2. CONCLUSION: The combination of hyperbaric oxygen with temozolomide produced an important reduction in glioma growth and effective approach to the treatment of glioblastoma.(AU)

OBJETIVO: A temozolomida (TMZ) tem atividade anti-tumoral em pacientes com glioma maligno. Oxigênio hiperbárico (HBO) pode aumentar a eficácia de terapias que são limitadas devido a um microambiente do tumor hipóxico. Foram examinados os efeitos combinados de TMZ-HBO em um modelo de glioma em rato. MÉTODOS: Após a injeção estereotáxica de células de glioma de rato C6/LacZ no cérebro de ratos Wistar, os ratos foram distribuídos aleatoriamente em três grupos de tratamento: Grupo 1: tratamento de controle. Grupo 2: TMZ sozinho. Grupo 3: uma combinação de TMZ e HBO. Os ratos foram sacrificados 18 dias após o tratamento. Foram avaliados o número de vasos intra-/peri-tumoral, proliferação microendotelial, imunohistoquímica e área necrótica . RESULTADOS: O tecido tumoral foi marcado apenas esparsamente com GFAP. O tratamento com temozolomida diminuiu significativamente o tecido intratumoral e a área total do tumor. O nível de Ki67 foi significativamente diminuído no tecido do tumor do grupo 3. Além disso, a superfície necrótica total / volume total do tumor (%) diminuiu significativamente no tecido do tumor do grupo 3 em comparação com grupo 1 e 2. CONCLUSÃO: A combinação de oxigênio hiperbárico com temozolomida produziu uma redução importante no crescimento do glioma podendo ser abordagem eficaz para o tratamento do glioblastoma.(AU)

Crohn's disease and hyperbaric oxygen therapy / Doença de Crohn e oxigenoterapia hiperbárica

PURPOSE: Evaluate the application of Hyperbaric Oxygen Therapy (HBO) in patients with Crohn's disease (CD) refractory to pharmacologic therapy, who developed abdominal, anorectal or skin complications. METHODS: Fourteen selected patients with refractory CD and treated at the School of Medicine of Ribeirao Preto, University of Sao Paulo (FMRP-USP) and at the Center of Hyperbaric Medicine, São Paulo Hospital (CEMEHI) were submitted to HBO. RESULTS: Of the 14 patients evaluated, 11 had a satisfactory response. CONCLUSION: HBO has shown benefits in patients with CD refractory to pharmacologic therapy.(AU)

OBJETIVOS: Avaliar a aplicação da Oxigenoterapia Hiperbárica (HBO) nos pacientes com doença de Crohn (CD), refratários a terapia farmacológica, que evoluíram com complicações abdominais, orificiais ou dermatológicas. MÉTODOS: Catorze pacientes selecionados no Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo e no Centro de Medicina Hiperbárica do Hospital São Paulo de Ribeirão Preto eram portadores de Doença de Crohn refratária ao tratamento farmacológico e foram submetidos a sessões de HBO. RESULTADOS: Dos 14 pacientes avaliados, 11 apresentaram resposta satisfatória. CONCLUSÃO: A HBO tem demonstrado benefício nos pacientes com Doença de Crohn refratários ao tratamento farmacológico.(AU)

Effect of hyperbaric oxygen therapy in rats with subtotal splenectomy preserving the inferior pole / Efeito da oxigenoterapia hiperbárica em ratos submetidos à esplenectomia subtotal com preservação do polo inferior

PURPOSE: To evaluate the effect of hyperbaric oxygen therapy on the survival and weight of rats submitted to subtotal splenectomy and on the viability and growth of the inferior pole. METHODS: Forty Wistar rats underwent subtotal splenectomy with preservation of the inferior pole and distributed into two groups: Group A (n=20) - not treated with hyperbaric oxygen, Group B (n=20) - treated with hyperbaric oxygen. These groups were divided into two subgroups of 10 animals each, according to the time of euthanasia, 15th and 45th days. The survival and weight of the animals were recorded. The inferior pole was measured, weighed and morphologically analyzed. RESULTS: All animals survived. The weight of the animals increased in all subgroups, but decreased on the 10th day in the subgroups treated with hyperbaric oxygen (p<0.001). The viability of the inferior pole was more evident in animals treated on the 15th day, but did not differ on the 45th day. The growth of the inferior pole has not occurred on the 15th day but on the 45th day after surgery in untreated animals (p<0.01) and treated animals (p<0.05). Vascular and cellular increase in treated animals was significantly higher than in untreated ones. CONCLUSION: Hyperbaric oxygen therapy did not affect the survival of animals but reduced their weight. It improved the viability of the inferior splenic pole, but did not interfere with their growth.(AU)

OBJETIVO: Avaliar o efeito da oxigenoterapia hiperbárica na sobrevida e peso de ratos submetidos à esplenectomia subtotal e na viabilidade e crescimento do polo inferior. MÉTODOS: Quarenta ratos Wistar foram submetidos à esplenectomia subtotal com preservação do polo inferior e distribuídos em dois grupos: A (n=20) v - não tratados com oxigênio hiperbárico, B (n=20) - tratados. Esses grupos foram divididos em dois subgrupos de 10 animais cada, de acordo com a época de eutanásia: 15º e 45º dias. A sobrevida e peso dos animais foram anotadas. O pólo inferior foi medido, pesado e analisado morfologicamente. RESULTADOS: Todos os animais sobreviveram. O peso aumentou em todos os subgrupos, porém diminuiu no 10º dia nos subgrupos tratados com oxigênio hiperbárico (p<0,001). A viabilidade do polo inferior foi mais evidente nos animais tratados no 15º dia, porém não diferiu no 45º dia. O crescimento do polo inferior não ocorreu no 15º e sim no 45º dia pós-operatório, nos animais não tratados (p<0,01) e tratados (p<0,05). O aumento celular e vascular nos animais tratados foi mais significativo do que nos animais não tratados. CONCLUSÃO: A oxigenoterapia hiperbárica não interferiu na sobrevida dos animais, porém diminuiu o peso. Melhorou a viabilidade do polo inferior do baço, mas não interferiu no seu crescimento.(AU)

Effect of hyperbaric oxygen therapy on the intestinal ischemia reperfusion injury / Efeito da oxigenoterapia hiperbárica na lesão por isquemia reperfusão intestinal

PURPOSE: Adequate tissue oxygenation is essential for healing. Hyperbaric oxygen therapy (HBOT) has potential clinical applications to treat ischemic pathologies, however the exact nature of any protective effects are unclear at present. We therefore investigated the potential role of HBOT in modulating the ischemia/reperfusion (I/R) injury response in intestinal model of I/R injury. METHODS: Male Wistar rats were subjected to surgery for the induction of intestinal ischemia followed by reperfusion. HBOT was provided before and/or after intestinal ischemia. Cell viability in the intestinal tissue was assessed using the MTT assay and by measuring serum malondealdehyde (MDA). Microvascular density and apoptosis were evaluated by immunohistochemistry. RESULTS: The results indicate that HBOT treatment pre- and post-ischemia reduces lesion size to the intestinal tissue. This treatment increases cell viability and reduces the activation of caspase-3, which is associated with increased number of tissue CD34 cells and enhanced VEGF expression. CONCLUSION: The hyperbaric oxygen therapy can limit tissue damage due to ischemia/reperfusion injury, by inducing reparative signaling pathways.(AU)

OBJETIVO: Oxigenação tissular adequada é essencial para cicatrização. Oxigenoterapia hiperbárica (HBOT) tem aplicação clínica para tratar lesões isquêmicas, entretanto a natureza exata dos mecanismos envolvidos permanece incerta. Procuramos investigar o papel potencial da HBOT na modulação da resposta a uma lesão por isquemia reperfusão (I/R) intestinal em modelo de lesão de I/R. MÉTODOS: Ratos machos Wistar foram submetidos à cirurgia para a indução da isquemia intestinal seguida de reperfusão. HBOT foi fornecido antes e / ou após a isquemia intestinal. A viabilidade das células no tecido intestinal foi avaliada através do ensaio de MTT e pela medição malondealdeido (MDA) no plasma. Densidade microvascular e apoptose foram avaliados por imuno-histoquímica. RESULTADOS: Os resultados indicam que o tratamento HBOT pré e pós-isquemia reduz o tamanho da lesão ao tecido intestinal. Este tratamento aumenta a viabilidade celular e reduz a ativação da caspase-3, que está associada com aumento do número de células CD 34 no tecido e da expressão da VEGF. CONCLUSÃO: A oxigenoterapia hiperbárica pode limitar os danos do tecido devido à lesão por isquemia/reperfusão, induzindo às vias de sinalização reparadora.(AU)