Performance during a strenuous swimming session is associated with high blood lactate: pyruvate ratio and hypoglycemia in fasted rats

The aim of this study was to investigate the effect of lactatemia elevation and glycemia reduction on strenuous swimming performance in fasted rats. Three rats were placed in a swimming tank at the same time. The first rat was removed immediately (control group) and the remaining ones were submitted to a strenuous swimming session. After the second rat was exhausted (Exh group), the third one was immediately removed from the water (Exe group). According to the period of time required for exhaustion, the rats were divided into four groups: low performance (3-7 min), low-intermediary performance (8-12 min), high-intermediary performance (13-17 min), and high performance (18-22 min). All rats were removed from the swimming tanks and immediately killed by decapitation for blood collection or anesthetized for liver perfusion experiments. Blood glucose, lactate, and pyruvate concentrations, blood lactate/pyruvate ratio, and liver lactate uptake and its conversion to glucose were evaluated. Exhaustion in low and low-intermediary performance were better associated with higher lactate/pyruvate ratio. On the other hand, exhaustion in high-intermediary and high performance was better associated with hypoglycemia. Lactate uptake and glucose production from lactate in livers from the Exe and Exh groups were maintained. We concluded that there is a time sequence in the participation of lactate/pyruvate ratio and hypoglycemia in performance during an acute strenuous swimming section in fasted rats. The liver had an important participation in preventing hyperlactatemia and hypoglycemia during swimming through lactate uptake and its conversion to glucose.

Effect of short-term ornithine alpha-ketoglutarate pretreatment on intestinal ischemia-reperfusion in rats / Efeitos do pré-tratamento em curto prazo com ornitina alfa-cetoglutarato na isquemia-reperfusão intestinal em ratos

PURPOSE: To investigate the effects of preventive enteral administration of ornithine alpha-ketoglutarate (OKG) in an ischemia-reperfusion rat model. METHODS: Sixty rats were randomized into five groups (G1-G5, n = 12). Each group was divided into two subgroups (n = 6) and treated with calcium carbonate (CaCa) or OKG by gavage. Thirty minutes later, the animals were anesthetized with xylazine 15mg + ketamine 1mg ip and subjected to laparotomy. G1-G3 rats served as controls. Rats in groups G4 and G5 were subjected to ischemia for 30 minutes. Ischemia was achieved by clamping the small intestine and its mesentery, delimiting a segment of bowel 5 cm long and 5 cm apart from the ileocecal valve. In addition, G5 rats underwent reperfusion for 30 minutes. Blood samples were collected at the end of the laparotomy (G1), after 30 minutes (G2, G4) and 60 minutes (G3, G5) to determine concentrations of metabolites (pyruvate, lactate), creatine phosphokinase (CPK), thiobarbituric acid reactive substances (TBARS) and glutathione (GSH). RESULTS: There was a significant decrease in tissue pyruvate and lactate and plasma CPK levels in OKG-treated rats at the end of reperfusion period. GSH levels did not change significantly in ischemia and reperfusion groups. However, TBARS levels increased significantly (p<0.05) in tissue samples in OKG-treated rats subjected to ischemia for 30 minutes. CONCLUSION: Short-term pretreatment with OKG before induction of I/R decreases tissue damage, increases pyruvate utilization for energy production in the Krebs cycle and does not attenuate the oxidative stress in this animal model.

OBJETIVO: Investigar os efeitos da administração enteral preventiva de ornitina alfa-cetoglutarato (OKG) em modelo de isquemia-reperfusão no rato. MÉTODOS: Sessenta ratos foram randomizados em cinco grupos (G1-G5, n=12). Cada grupo foi redistribuído em dois subgrupos (n=6) e tratado com carbonato de cálcio (CaCa) ou OKG por gavagem. Trinta minutos mais tarde, os animais foram anestesiados com xilazina 1mg+cetamina 15mg i.p. e submetidos à laparotomia. Os ratos dos grupos G4-G5 foram submetidos à isquemia por 30 minutos. A isquemia foi obtida por pinçamento do intestino delgado, delimitando um segmento com 5 cm de comprimento e distando 5 cm da válvula ileocecal. O grupo G5 foi submetido à reperfusão por 30 minutos. Amostras de sangue foram coletadas no final da laparotomia (G1), após 30 minutos (G2, G4) e 60 minutos (G3, G5) para determinação das concentrações de metabolitos (piruvato, lactato), creatinofosfoquinase (CPK), substâncias reativas ao ácido tiobarbitúrico (TBARS) e glutationa (GSH). RESULTADOS: Observou-se redução significante (p<0,05) das concentrações de piruvato e lactato, teciduais e CPK plasmático em ratos tratados com OKG, no final do período de reperfusão. Não houve alteração significante nos níveis plasmáticos e teciduais de GSH. Entretanto os níveis de TBARS aumentaram significativamente (p<0,05) em amostras de tecido de ratos tratados com OKG submetido à isquemia por 30 minutos. CONCLUSÃO: o pré-tratamento em curto prazo com OKG antes da indução da I/R diminui a lesão tecidual, aumenta a utilização de piruvato para produção de energia no ciclo de Krebs, mas não atenua o estresse oxidativo neste modelo animal.

Metabolic and oxidative effects of sevoflurane and propofol in children undergoing surgery for congenital heart disease / Efeitos metabólicos e oxidativos do sevoflurano e do propofol em crianças portadoras de cardiopatia congênita submetidas à cirurgia

PURPOSE: To evaluate the metabolic and oxidative effects of sevoflurane and propofol in children undergoing surgery for correction of congenital heart disease. METHODS: Twenty children with acyanotic congenital heart disease, scheduled for elective cardiac surgery with cardiopulmonary bypass, age range 1 day to 14 years were randomly assigned to 2 groups: Group GP, programmed to receive total intravenous anesthesia with propofol and group GS scheduled to use balanced anesthesia with sevoflurane. Exclusion criteria were cyanotic heart disease or complex, association with other malformations, severe systemic diseases, infection or children undergoing treatment and palliative or emergency surgery. Blood samples were collected at three different time-points: T0, after radial artery cannulation, T1, 30 minutes after cardiopulmonary bypass (CPB) launch and T2, at the end of procedure. Parameters analyzed included thiobarbituric acid-reactive substance (TBARS), glutathione (GLN), lactate and pyruvate plasmatic concentrations. RESULTS: TBARS, GSH, lactate and pyruvate concentrations did not change significantly by Friedman´s test. Lactate/pyruvate ratio (L/P) was >10 in both groups. There was a moderate Pearson correlation for TBARS, in T1 (r=0.50; p=0.13) e T2 (r=0.51;p=0.12). Pearson correlation was high between groups during CPB (T1) for lactate (r=0.68; p=0.02), pyruvate (r=0.75; p=0.01) and L/P ratio (r=0.83; p=0.003). CONCLUSION: Anesthetic techniques investigated in this study showed a similar pattern, with no increase in metabolic substrates and oxidative stress during surgical correction of congenital heart defects in non-cyanotic children.

OBJETIVO: Avaliar os efeitos metabólicos e oxidativos da anestesia com sevoflurano ou propofol em crianças portadoras de cardiopatia congênita, submetidas à cirurgia eletiva. MÉTODOS: Vinte crianças com cardiopatia congênita acianótica, agendadas para a cirurgia cardíaca eletiva com circulação extracorpórea (CEC), idades 1 dia-14 anos, foram distribuídas aleatoriamente em dois grupos: Grupo GP (anestesia venosa total com propofol) e grupo GS (anestesia balanceada com sevoflurano). Critérios de exclusão foram: doença cardíaca cianótica ou complexa, associação com outras malformações, doença sistêmica grave, infecção ou crianças submetidas a tratamento e cuidados paliativos ou cirurgia de emergência. Amostras de sangue foram coletadas em três horários diferentes: T0, após a canulação da artéria radial, T1, 30 minutos após o início da CEC e T2, no final do procedimento. Parâmetros analisados: substâncias reativas ao ácido tiobarbitúrico (TBARS), glutationa (GLN), lactato e piruvato. RESULTADOS: As concentrações de TBARS, GSH, lactato e piruvato não foram diferentes (teste de Friedman). A razão Lactato/piruvato (L/P) foi >10 em ambos os grupos. Houve uma correlação de Pearson moderada no TBARS, em T1 (r = 0,50, p = 0,13) e T2 (r = 0,51, p = 0,12). A correlação de Pearson foi alta entre os grupos durante a CEC (T1) para lactato (r=0,68, p=0,02), piruvato (r=0,75, p=0,01) e relação L/P (r =0,83, p=0,003). CONCLUSÃO: As técnicas anestésicas investigadas mostraram um padrão semelhante, sem aumento de substratos metabólicos ou do estresse oxidativo durante a correção cirúrgica de cardiopatias congênitas em crianças acianóticas.

Effect of chemotherapy on serum lactate levels in malignant neoplasia

The present study was designed to look at the levels of serum lactate in various malignancies and to observe the effect of chemotherapy on serum lactate concentration in malignant neoplasia as a whole. The study was also intended to look for the difference, if any, in this effect for haematopoietic and non-haematopoietic neoplasias, so as to see whether evaluation of lactate levels could represent an additional and useful parameter in determining the clinical and prognostic aspect of the disease Observational and comparative study. This study was conducted at Radiotherapy Department, Jinnah Postgraduate Medical Centre, Karachi In this study 131 patients of Malignant Neoplasia were taken from the out-door patients in which 56 patients of haematopoietic group and 75 patients of non- haematopoietic group. Blood samples of 131 patients suffering from haematopoietic and non-haematopoietic neoplasia and 20 healthy control subjects were collected and analyzed for lactate, pyruvate and the NADH/NAD ratio. Blood lactate, Pyruvate levels and NADH/NAD* ratio were significantly higher in all groups of neoplasia before chemotherapy when compared with control subjects. The NADH/NAD+ ratio and the levels of blood lactate and Pyruvate decreased significantly with chemotherapy in all groups of patients suffering from neoplasia. Observation of low levels of these parameters, particularly that of serum lactate, after the course of chemotherapy can be used as an indicator of prognosis and also considered helpful in assessing the effectiveness of chemotherapy in malignancies

Is subdiaphragmatic aortic cross-clamping a suitable model for spinal cord ischemia/reperfusion injury study in rats?

OBJETIVO: Avaliar a eficácia do pinçamento da aorta subdiafragmática no modelo experimental de isquemia/reperfusão da medula espinhal em ratos. Trinta e seis ratos Wistar, machos, foram aleatoriamente distribuídos em 2 grupos (n=18) e submetidos ao pinçamento subdiafragmático da aorta, durante 30 minutos (Grupo-2 -Isquemia/Reperfusão). Os ratos do Grupo-1 (G-1 - Sham) foram utilizados como controles e submetidos a laparotomia sem pinçamento arterial. As amostras (medula e sangue arterial) foram coletadas ao término do período de isquemia (T-0) e 10 (T-10) e 20 (T-20) minutos mais tarde e nos mesmos intervalos, no grupo G-1. As concentrações teciduais e sanguíneas de piruvato, lactato, glicose e as concentrações medulares de trifosfato de adenosina (ATP) foram determinadas por ensaios enzimáticos. RESULTADOS: As concentrações de piruvato e glicose (sangue e tecido) e de lactato e ATP (medula) não foram diferentes,comparando G-1 versus G-2. A lactacemia elevou-se significantemente no G-2, comparado ao G-1, durante a reperfusão (T-10). CONCLUSÃO: O modelo experimental de pinçamento subdiafragmático da aorta não é adequado para o estudo da lesão de isquemia/reperfusão na medula de ratos, uma vez que não proporciona alterações nas concentrações in vivo de metabólitos teciduais, por exemplo de lactato ou ATP, compatíveis com aquelas encontradas em tecidos sujeitos à isquemia/reperfusão.

Effects of L-alanyl-glutamine upon the blood and kidney biochemical parameters in the rat hind limb model of ischemia/reperfusion

OBJETIVO: Investigar alterações dos parâmetros metabólicos no sangue e rim de ratos submetidos à isquemia/reperfusão do membro pélvico. MÉTODOS: Quarenta e oito ratos machos foram distribuídos aleatoriamente em 2 grupos pré-tratados com administração intragástrica de solução salina 2,0 mL (G-1) ou L-alanil-glutamina 0,75 mgKg-1(G-2), uma vez ao dia (7:00h) durante 7 dias. Uma hora após a última gavagem todos os ratos foram anestesiados com éter dietílico, laparotomizados e submetidos ao pinçamento da artéria de ilíaca esquerda, durante 3 horas. Amostras foram coletadas ao término de isquemia e durante a reperfusão (1-3-6h) para determinação das concentrações in vivo de piruvato, lactato, glicose e corpos cetônicos (rim e sangue) e ATP (rim). RESULTADOS: Lactacemia e cetonemia aumentaram no grupo G-2 quando comparadas às aferidas em ratos não-tratados, durante a reperfusão. As concentrações de piruvato diminuíram e de lactato aumentaram significativamente no rim, durante a reperfusão (1h, 3h) em ratos do G-2 comparados aos respectivos controles. Houve um aumento significante nas concentrações renais de glicose, ATP e corpos cetônicos nos ratos tratados com L-alanil-glutamina durante a reperfusão (3h). CONCLUSÕES: A isquemia do membro pélvico em ratos pré-tratados com L-alanil-glutamina induz aumento da lactacemia e da concentração de lactato renal, indicando atividade glicolítica aumentada na medula renal. A hipercetonemia induzida pela oferta do dipeptídeo sugere cetogênese elevada, sinalizada por possível queda nas concentrações plasmáticas de insulina resultante da maior oxidação de glicose e utilização desse hormônio em tecidos periféricos.

Effect of co-administration of cassava (Manihot esculenta Crantz) rich diet and alcohol in rats.

The effects of co-administration of a cassava rich diet and alcohol in rats were investigated. The animals were divided into four groups (1) Control, (2) Alcohol, (3) Cassava and (4) Alcohol + Cassava. Consumption of alcohol along with cassava reduced the alcohol induced toxicity which was evidenced by the lower activities of GOT, GPT, GGT, acid phosphatase and alkaline phosphatase in the liver and serum of co-administered group. The pyruvate content in the blood increased while the lactate content, lactate/pyruvate ratio and the activity of LDH decreased in the blood due to co-administration. The blood cyanide content, serum thiocyanate content and the activities of rhodanase and beta-glucuronidase increased on co-administration. The histopathological studies also revealed that co-administration reduced the alcohol induced toxicity.

Effects of spinal anaesthesia on metabolic processes.

A study conducted at P.G.I., Chandigarh to find out the effect of spinal anaesthesia on arterial blood gases, blood glucose, and pyruvate-lactate during spinal anaesthesia. All patients received night sedation of oral diazepam in dose of 0.2 mg/kg body weight. No narcotic/antisialogogue premedication was given to any patient. All patients received spinal anaesthesia with 5% lignocaine (hyperbaric), in lateral position. All patients received normal saline intravenously as a maintenance fluid. Blood samples for the measurement of blood pyruvate, lactate levels and arterial blood gas analysis were collected preoperatively, 10 minutes after the administration of spinal anaesthesia after fixation of drug, and half hour after the end of operative procedure. Even though there was continued rise in blood sugar levels intraoperatively, which persisted in postoperative period, the values were within normal clinical range. Blood lactate levels and blood pyruvate levels remained unchanged. Hypocapnoea observed intra-operatively in our report is attributed to hyperventilation. There was 12.44% fall in bicarbonate level. (P > .001) which even though statistically significant did not alter the pH. We conclude that spinal anaesthesia up to T8 level does not affect the metabolic processes.