Lentiviral-mediated RNAi targeting caspase-3 inhibits apoptosis induced by serum deprivation in rat endplate chondrocytes in vitro

Current studies find that degenerated cartilage endplates (CEP) of vertebrae, with fewer diffusion areas, decrease nutrient supply and accelerate intervertebral disc degeneration. Many more apoptotic cells have been identified in degenerated than in normal endplates, and may be responsible for the degenerated grade. Previous findings suggest that inhibition of apoptosis is one possible approach to improve disc regeneration. It is postulated that inhibition of CEP cell apoptosis may be responsible for the regeneration of endplates. Caspase-3, involved in the execution phase of apoptosis, is a candidate for regulating the apoptotic process. In the present study, CEP cells were incubated in 1% fetal bovine serum. Activated caspases were detected to identify the apoptotic pathway, and apoptosis was quantified by flow cytometry. Lentiviral caspase-3 short hairpin RNA (shRNA) was employed to study its protective effects against serum deprivation. Silencing of caspase-3 expression was quantified by reverse transcription-polymerase chain reaction and Western blots, and inhibition of apoptosis was quantified by flow cytometry. Serum deprivation increased apoptosis of rat CEP cells through activation of a caspase cascade. Lentiviral caspase-3 shRNA was successfully transduced into CEP cells, and specifically silenced endogenous caspase-3 expression. Surviving cells were protected by the downregulation of caspase-3 expression and activation. Thus, lentiviral caspase-3 shRNA-mediated RNAi successfully silenced endogenous caspase-3 expression, preventing inappropriate or premature apoptosis.

Aminotransferases activity in the hemolymph of Bradybaena similaris (Gastropoda, Xanthonychidae) under starvation

Aminotransferases (GOT and GPT) activities in the hemolymph of Bradybaena similaris under experimental condition of starvation were studied. At the 10th day of starvation, GOT activity was 416.6 percent higher than that observed in the fed snails, being reduced and ranging values near to that shown by the control group onwards. GPT activity only varied significantly at the day-30 of starvation. The results were discussed

Changes in body fluid and energy compartments during prolonged hunger strike

Prolonged total food deprivation in non-obese adults is rare, and few studies have documented body composition changes in this setting. In a group of eight hunger strikers who refused alimentation for 43 days, water and energy compartments were estimated, aiming to assess the impact of progressive starvation. Measurements included body mass index (BMI), triceps skinfold (TSF), arm muscle circumference (AMC), and bioimpedance (BIA) determinations of water, fat, lean body mass (LBM), and total resistance. Indirect calorimetry was also performed in one occasion. The age of the group was 43.3+/-6.2 years (seven males, one female). Only water, intermittent vitamins and electrolytes were ingested, and average weight loss reached 17.9 percent. On the last two days of the fast (43rd-44th day) rapid intravenous fluid, electrolyte, and vitamin replenishment were provided before proceeding with realimentation. Body fat decreased approximately 60 percent (BIA and TSF), whereas BMI reduced only 18 percent. Initial fat was estimated by BIA as 52.2+/-5.4 percent of body weight, and even on the 43rd day it was still measured as 19.7+/-3.8 percent of weight. TSF findings were much lower and commensurate with other anthropometric results. Water was comparatively low with high total resistance, and these findings rapidly reversed upon the intravenous rapid hydration. At the end of the starvation period, BMI (21.5+/-2.6 kg/m2) and most anthropometric determinations were still acceptable, suggesting efficient energy and muscle conservation. Conclusions: 1) All compartments diminished during fasting, but body fat was by far the most affected; 2) Total water was low and total body resistance comparatively elevated, but these findings rapidly reversed upon rehydration; 3) Exaggerated fat percentage estimates from BIA tests and simultaneous increase in lean body mass estimates suggested that this method was inappropriate for assessing energy compartments in the studied population; 4) Patients were not morphologically malnourished after 43 days of fasting; however, the prognostic impact of other impairments was not considered in this analysis

Suporte nutricional no paciente grave / Nutritional support in the critically ill patient

O moderno suporte nutricional representa, inquestionavelmente, um importante avanço da medicina neste século, sendo o paciente cirúrgico um dos maiores beneficiados. Na última década, conceitos foram revistos. A quantidade de nutrientes administrada foi reduzida com base em estudos experimentais e clínicos que mostraram que a hipernutriçäo pode ser täo danosa quanto a desnutriçäo. As indicaçöes de suporte nutricional pré-operatório, no paciente com desnutriçäo leve ou moderada, näo reduz complicaçöes pós-operatórias. Mas a maior mudança ocorreu na via de administraçäo de nutrientes. A nutriçäo parenteral deu lugar à nutriçäo enteral e, graças a melhora dos recursos técnicos para administraçäo e das soluçöes nutricionais, hoje, possível nutrir pela via enteral mesmo pacientes com limitaçöes severas do trato digestivo. O reconhecimento da importância da presença de nutrientes na luz do tubo digestivo teve papel essencial nesta mudança. Em anos recentes, os nutrientes passaram a ser concebidos também como agentes farmacológicos. A glutamina, os ácidos graxos "mega-3 e a arginina säo usados hoje como coadjuvantes de outras intervençöes terapêuticas em várias condiçöes clínicas. Em algumas situaçöes específicas, o suporte nutricional tem um papel central no tratamento. As fístulas digestivas, as sepses abdominais, a pancreatite aguda e a síndrome do intestino curto säo exemplos marcantes.

Effect of fasting on myocardial glucose uptake in rabbits

In the present study, the effect of fasting on myocardial glucose uptake was studied. Two different techniques were used, namely cardiac muscle slices [0.5 mm thick] and the isolated heart perfusion using Langendorff's coronary technique. The effect of fasting for 1, 2, 3 and 4 days on glucose uptake was studied in both groups of experiments and the results were compared with control fed animals. The present results showed that in both groups of experiments [slices and isolated heart perfusion], fasting caused a significant increase in glucose uptake, an effect which was potentiated by increasing the duration of fasting. These results differed from previous studies which reported decreased glucose uptake by starvation. This difference could be explained by the difference in the substrate used, since previous studies used glucose and free fatty acids in the used solution or injected radioactive glucose in vivo then measured radioactivity after killing the animals, while in the present study glucose only was used as a substrate. The increase in glucose uptake could, also, be explained by its use for glycogen synthesis in cardiac muscle

Renal sodium conservation during starvation in rats

The natriuresis of fasting has been well characterized in man and rabbits but not in rats. The daily effects of fasting on glomerular filtration rate (GFR) and urinary sodium and potassium excretion were evaluated in Munich-Wistar rats (260-310 g) submitted to prolonged starvation (2-8 days). Rats do not present the natriuresis of fasting. Sodium excretion was reduced since the first few hours (0-4 h) of starvation. Antinatriuresis was abrupt during the early periods (1st and 2nd days) and stabilized at very low levels. During the early phase (4 days), sodium retention occurred due to both reduced glomerular filtration and increased tubular reabsorption. However, during the late phase (after the 4th day), antinatriuresis was mainly induced by the elevation in tubular reabsorption, since a normalization of GFR was observed. Thus, these homeostatic mechanisms permit adequate renal sodium conservation during starvation in rats

Effect of prolonged starvation and refeeding on fuel metabolism in rats.

Body and liver weights, Liver lipids, glycogen, aspartate aminotransferase (EC 2.6.1.1), alanine aminotransferase (EC 2.6.1.2) and blood glucose levels were determined in starved and starved-refed rats. Decrease in body and liver weights was rapid during the initial stage of starvation and slowed down thereafter. Water was the major liver constituent lost in early fast. Following 10 days of starvation, body weight was reduced by nearly 20%, liver weight 43%, liver glycogen 93% and blood glucose 34%. Liver lipids and the activities of the two transaminases however, were increased by about 30-50%. On refeeding body weight and its water content increased and became nearly double of the initial fasting value on day 2. Blood glucose, liver glycogen, liver lipids and transaminases were significantly altered and got normalised within 5-8 days.

Acetylcholine levels of rat brain and heart in starvation and protein restriction.

Acetylcholine (ACh) levels and protein content in brain and heart were determined in normal, acutely starved, chronically semi-starved and chronically protein restricted groups of adult male rats. The only change observed in acute starvation and chronic semi-starvation was an increase in ACh level with a decrease in protein content in the heart, no change was observed in the brain. Protein restriction, however, produced a significant rise in ACh levels with a decrease in protein content of both brain and heart.

Effect of different dietary carbohydrates on some hepatic dehydrogenases and total lipid during starvation and refeeding regimen.

Lipogenic capacity of various dietary carbohydrates starch, glucose sucrose and lactose was tested during ad lib feeding and starvation followed by refeeding. Sucrose was found to have maximal effect on hepatic total lipid and the enzymes in the study followed by glucose and sago while lactose was found to be toxic. Starvation resulted depression in the activities of various enzymes. The enzyme activity inducing effect was again exhibited by sucrose diet during ad lib and restricted refeeding followed by starvation.