Efeitos do estresse de manipulação sobre marcadores metabólicos e fisiológicos do caranguejo Ocypode quadrata (Crustacea, Ocypodidae)

O caranguejo popularmente chamado de Maria-farinha (ou Ghost crab), Ocypode quadrata, é encontrado em praias ao longo do Oceano Atlântico ocidental, desde Rhode Island (EUA) até o Rio Grande do Sul. Essa espécie tem sido considerada como bioindicadora da saúde de praias arenosas, uma vez que as atividades humanas nas praias causam impacto negativo sobre suas populações. O presente trabalho tem por objetivo avaliar os efeitos do estresse de manipulação sobre parâmetros metabólicos e fisiológicos. Os caranguejos (47 machos e 19 fêmeas), foram coletados na praia de Quintão (RS). No laboratório, os animais foram mantidos em terrários e alimentados ad libitum em dias alternados por um período de aclimatação de 15 dias. A salinidade foi mantida em 30%o, a temperatura em 25⁰C e fotoperíodo natural. Após o período de aclimatação, os animais foram acondicionados individualmente e privados de alimentação por três horas. Após isso, os animais eram submetidos, um a um, ao protocolo de estresse de manipulação. Em seguida ao protocolo de estresse de manipulação, os animais foram submetidos a diferentes tempos de recuperação. Após o término da recuperação, foram coletadas amostras de hemolinfa e, logo após, os caranguejos foram crioanestesiados para coleta dos tecidos. O estresse de manipulação de 5 minutos não foi capaz de provocar mudanças significativas em nenhum dos tempos de recuperação (30min e 60min), em variáveis como colesterol e proteínas totais, ambos na hemolinfa, tampouco nas concentrações de glicogênio no hepatopâncreas e coração, triglicerídeos no hepatopâncreas e lactato muscular. Na hemolinfa, a concentração de triglicerídeos reduziu 30 minutos após a manipulação, a glicemia elevou-se aos 30 e 60 minutos enquanto a concentração de lactato circulante elevou-se imediatamente após a manipulação e diminuiu 60 minutos após. A concentração de glicogênio muscular dos caranguejos aumentou 30 minutos de recuperação. A expressão gênica de CHH e de HSP70 não apresentou diferença significativa após 60min de recuperação do estresse de manipulação em nenhum dos tecidos analisados. Esses resultados sugerem que há gliconeogênese intramuscular utilizando lactato como substrato. Ainda percebe-se um efeito poupador de glicose resultado da utilização desse lactato muscular somado à utilização dos triglicerídeos da hemolinfa, priorizando a glicose hemolinfática para o funcionamento do sistema nervoso central do animal. Novas investigações no que concerne ao destino do lactato formado durante trabalho muscular intenso com maiores tempos de recuperação são necessárias, bem como a expressão tanto de CHH e HSP70 nestas novas condições.The Ghost crab Ocypode quadrata, found in sandy beaches along the western Atlantic Ocean, from Rhode Island (USA) to Rio Grande do Sul, has been considered a potential bioindicator of health of sandy beaches because human activities on the beaches cause negative impact on its populations. The present work aims to evaluate the effects of handling stress on metabolic and physiological parameters of this crab. The crabs (47 males and 19 females) were collected on Quintão (RS). In the laboratory, the animals were kept in terrariums and fed ad libitum every other day during a 15 days acclimation period. The salinity was 30%o, the temperature 25°C and natural photoperiod. After the acclimation period, the animals were individually conditioned and deprived of food for 3 hours. After that, each crab was handled and not allowed to rest for 5 minutes. Following this protocol, the animals were submitted to different recovery times. After the recovery was completed, hemolymph samples were collected and, shortly thereafter, the crabs were cryoanesthetized for tissue collection.The 5-minute handling stress was not able to induce significant changes in any of the recovery times (30min and 60min) in variables such as cholesterol and total proteins, both in hemolymph, nor in glycogen concentrations in the hepatopancreas and heart, triglycerides in the hepatopancreas and muscular lactate. In hemolymph, triglycerides reduced 30 minutes after the manipulation; the glycemia increased at 30 and 60 minutes while the lactate concentration was elevated immediately after the manipulation and decreased 60 minutes after. The muscle glycogen concentration of the crabs increased at 30 minutes. The expression of CHH and HSP70 did not show significant difference after 60min recovery in any of the tissues analyzed. These results suggest that there is intramuscular gluconeogenesis using lactate as the substrate. A glucose-sparing effect is suggested as the sum of muscular glyconeogensis and the use of hemolymph triglycerides, prioritizing hemolytic glucose for the central nervous system functioning of the animal. New investigations as to the fate of lactate formed during intense muscle work with longer recovery times are required, as well as the expression of both CHH and HSP70 under these new conditions

Metabolic and molecular subacute effects of a single moderate-intensity exercise bout, performed in the fasted state, in obese male rats

Introduction and objectives: Obesity represents a major global public health problem. Its etiology is multifactorial and includes poor dietary habits, such as hypercaloric and hyperlipidic diets (HFDs), physical inactivity, and genetic factors. Regular exercise is, per se, a tool for the treatment and prevention of obesity, and recent studies suggest that the beneficial effects of exercise can be potentiated by the fasting state, thus potentially promoting additional effects. Despite the significant number of studies showing results that corroborate such hypothesis, very few have evaluated the effects of fasted-state exercise in overweight/obese populations. Therefore, the aim of this study was to evaluate the subacute effects (12 h after conclusion) of a single moderate-intensity exercise bout, performed in either a fed or an 8 h fasted state, on serum profile, substrate-content and heat shock pathway–related muscle protein immunocontent in obese male rats. Methods: Male Wistar rats received a modified high-fat diet for 12 weeks to induce obesity and insulin resistance. The animals were allocated to four groups: fed rest (FER), fed exercise (FEE), fasted rest (FAR) and fasted exercise (FAE). The exercise protocol was a 30 min session on a treadmill, with an intensity of 60% of VO2max. The duration of the fasting period was 8 h prior to the exercise session. After a 12 h recovery, the animals were killed and metabolic parameters of blood, liver, heart, gastrocnemius and soleus muscles were evaluated, as well as SIRT1 and HSP70 immunocontent in the muscles. Results: HFD induced obesity and insulin resistance. Soleus glycogen concentration decreased in the fasted groups and hepatic glycogen decreased in the fed exercise group. The combination of exercise and fasting promoted a decreased concentration of serum total cholesterol and triglycerides. In the heart, combination fasting plus exercise was able to decrease triglycerides to control levels. In the soleus muscle, both fasting and fasting plus exercise were able to decrease triglyceride concentrations. In addition, heat shock protein 70 and sirtuin 1 immunocontent increased after exercise in the gastrocnemius and soleus muscles. Conclusions: An acute bout of moderate intensity aerobic exercise, when realized in fasting, may induce, in obese rats with metabolic dysfunctions, beneficial adaptations to their health, such as better biochemical and molecular adaptations that last for at least 12 h. Considering the fact that overweight/obese populations present an increased risk of cardiovascular events/diseases, significant reductions in such plasma markers of lipid metabolism are an important achievement for these populations

Adipose tissue of female Wistar rats respond to Ilex paraguariensis treatment after ovariectomy surgery

Background and aim: Metabolic disturbances are known for their increasing epidemiological importance. Ilex paraguariensis presents a potential option for mitigating lipid metabolism imbalance. However, most of the literature to date has not considered sex bias. This study aimed to evaluate the effect of Ilex paraguariensis on the metabolism of different adipose tissue depots in males and females. Experimental procedure: After ovariectomy, female Wistar rats received daily treatment with the extract (1 g/kg) for forty-five days. Biochemical serum parameters and tissue metabolism were evaluated. Oxidation, lipogenesis and lipolysis were evaluated in brown, white visceral, retroperitoneal and gonadal adipose tissues. Results and conclusion: The results showed that treatment with the extract led to a reduced weight gain in ovariectomised females in comparison to control. The triglyceride concentration was decreased in males. Glucose oxidation and lipid synthesis in visceral and retroperitoneal adipose tissues were restored in ovariectomised females after treatment. The response to epinephrine decreased in visceral adipose tissue of control males; however, lipolysis in females did not respond to ovariectomy or treatment. These findings highlight the enormous potential effects of I. paraguariensis on lipid metabolism, modulating lipogenic pathways in females and lipolytic pathways in males. Furthermore, the sex approach applied in this study contributes to more effective screening of the effects of I. paraguariensis bioactive substances

Metabolic and Molecular Subacute Effects of a Single Moderate-Intensity Exercise Bout, Performed in the Fasted State, in Obese Male Rats

Introduction and objectives: Obesity represents a major global public health problem. Its etiology is multifactorial and includes poor dietary habits, such as hypercaloric and hyperlipidic diets (HFDs), physical inactivity, and genetic factors. Regular exercise is, per se, a tool for the treatment and prevention of obesity, and recent studies suggest that the beneficial effects of exercise can be potentiated by the fasting state, thus potentially promoting additional effects. Despite the significant number of studies showing results that corroborate such hypothesis, very few have evaluated the effects of fasted-state exercise in overweight/obese populations. Therefore, the aim of this study was to evaluate the subacute effects (12 h after conclusion) of a single moderate-intensity exercise bout, performed in either a fed or an 8 h fasted state, on serum profile, substrate-content and heat shock pathway–related muscle protein immunocontent in obese male rats. Methods: Male Wistar rats received a modified high-fat diet for 12 weeks to induce obesity and insulin resistance. The animals were allocated to four groups: fed rest (FER), fed exercise (FEE), fasted rest (FAR) and fasted exercise (FAE). The exercise protocol was a 30 min session on a treadmill, with an intensity of 60% of VO2max. The duration of the fasting period was 8 h prior to the exercise session. After a 12 h recovery, the animals were killed and metabolic parameters of blood, liver, heart, gastrocnemius and soleus muscles were evaluated, as well as SIRT1 and HSP70 immunocontent in the muscles. Results: HFD induced obesity and insulin resistance. Soleus glycogen concentration decreased in the fasted groups and hepatic glycogen decreased in the fed exercise group. The combination of exercise and fasting promoted a decreased concentration of serum total cholesterol and triglycerides. In the heart, combination fasting plus exercise was able to decrease triglycerides to control levels. In the soleus muscle, both fasting and fasting plus exercise were able to decrease triglyceride concentrations. In addition, heat shock protein 70 and sirtuin 1 immunocontent increased after exercise in the gastrocnemius and soleus muscles. Conclusions: An acute bout of moderate intensity aerobic exercise, when realized in fasting, may induce, in obese rats with metabolic dysfunctions, beneficial adaptations to their health, such as better biochemical and molecular adaptations that last for at least 12 h. Considering the fact that overweight/obese populations present an increased risk of cardiovascular events/diseases, significant reductions in such plasma markers of lipid metabolism are an important achievement for these populations

Efeitos do estresse de manipulação sobre marcadores metabólicos e fisiológicos do caranguejo Ocypode quadrata (Crustacea, Ocypodidae)

O caranguejo popularmente chamado de Maria-farinha (ou Ghost crab), Ocypode quadrata, é encontrado em praias ao longo do Oceano Atlântico ocidental, desde Rhode Island (EUA) até o Rio Grande do Sul. Essa espécie tem sido considerada como bioindicadora da saúde de praias arenosas, uma vez que as atividades humanas nas praias causam impacto negativo sobre suas populações. O presente trabalho tem por objetivo avaliar os efeitos do estresse de manipulação sobre parâmetros metabólicos e fisiológicos. Os caranguejos (47 machos e 19 fêmeas), foram coletados na praia de Quintão (RS). No laboratório, os animais foram mantidos em terrários e alimentados ad libitum em dias alternados por um período de aclimatação de 15 dias. A salinidade foi mantida em 30%o, a temperatura em 25⁰C e fotoperíodo natural. Após o período de aclimatação, os animais foram acondicionados individualmente e privados de alimentação por três horas. Após isso, os animais eram submetidos, um a um, ao protocolo de estresse de manipulação. Em seguida ao protocolo de estresse de manipulação, os animais foram submetidos a diferentes tempos de recuperação. Após o término da recuperação, foram coletadas amostras de hemolinfa e, logo após, os caranguejos foram crioanestesiados para coleta dos tecidos. O estresse de manipulação de 5 minutos não foi capaz de provocar mudanças significativas em nenhum dos tempos de recuperação (30min e 60min), em variáveis como colesterol e proteínas totais, ambos na hemolinfa, tampouco nas concentrações de glicogênio no hepatopâncreas e coração, triglicerídeos no hepatopâncreas e lactato muscular. Na hemolinfa, a concentração de triglicerídeos reduziu 30 minutos após a manipulação, a glicemia elevou-se aos 30 e 60 minutos enquanto a concentração de lactato circulante elevou-se imediatamente após a manipulação e diminuiu 60 minutos após. A concentração de glicogênio muscular dos caranguejos aumentou 30 minutos de recuperação. A expressão gênica de CHH e de HSP70 não apresentou diferença significativa após 60min de recuperação do estresse de manipulação em nenhum dos tecidos analisados. Esses resultados sugerem que há gliconeogênese intramuscular utilizando lactato como substrato. Ainda percebe-se um efeito poupador de glicose resultado da utilização desse lactato muscular somado à utilização dos triglicerídeos da hemolinfa, priorizando a glicose hemolinfática para o funcionamento do sistema nervoso central do animal. Novas investigações no que concerne ao destino do lactato formado durante trabalho muscular intenso com maiores tempos de recuperação são necessárias, bem como a expressão tanto de CHH e HSP70 nestas novas condições.The Ghost crab Ocypode quadrata, found in sandy beaches along the western Atlantic Ocean, from Rhode Island (USA) to Rio Grande do Sul, has been considered a potential bioindicator of health of sandy beaches because human activities on the beaches cause negative impact on its populations. The present work aims to evaluate the effects of handling stress on metabolic and physiological parameters of this crab. The crabs (47 males and 19 females) were collected on Quintão (RS). In the laboratory, the animals were kept in terrariums and fed ad libitum every other day during a 15 days acclimation period. The salinity was 30%o, the temperature 25°C and natural photoperiod. After the acclimation period, the animals were individually conditioned and deprived of food for 3 hours. After that, each crab was handled and not allowed to rest for 5 minutes. Following this protocol, the animals were submitted to different recovery times. After the recovery was completed, hemolymph samples were collected and, shortly thereafter, the crabs were cryoanesthetized for tissue collection.The 5-minute handling stress was not able to induce significant changes in any of the recovery times (30min and 60min) in variables such as cholesterol and total proteins, both in hemolymph, nor in glycogen concentrations in the hepatopancreas and heart, triglycerides in the hepatopancreas and muscular lactate. In hemolymph, triglycerides reduced 30 minutes after the manipulation; the glycemia increased at 30 and 60 minutes while the lactate concentration was elevated immediately after the manipulation and decreased 60 minutes after. The muscle glycogen concentration of the crabs increased at 30 minutes. The expression of CHH and HSP70 did not show significant difference after 60min recovery in any of the tissues analyzed. These results suggest that there is intramuscular gluconeogenesis using lactate as the substrate. A glucose-sparing effect is suggested as the sum of muscular glyconeogensis and the use of hemolymph triglycerides, prioritizing hemolytic glucose for the central nervous system functioning of the animal. New investigations as to the fate of lactate formed during intense muscle work with longer recovery times are required, as well as the expression of both CHH and HSP70 under these new conditions

Effects of organotins on crustaceans : update and perspectives

Organotins (OTs) are considered some of the most toxic chemicals introduced into aquatic environments by anthropogenic activities. They are widely used for agricultural and industrial purposes and as antifouling additives on boat hull’s paints. Even though the use of OTs was banned in 2008, elevated levels of OTs can still be detected in aquatic environments. OTs’ deleterious effects upon wildlife and experimental animals are well documented and include endocrine disruption, immunotoxicity, neurotoxicity, genotoxicity, and metabolic dysfunction. Crustaceans are key members of zooplankton and benthic communities and have vital roles in food chains, so the endocrine-disrupting effects of tributyltin (TBT) on crustaceans can affect other organisms. TBT can disrupt carbohydrate and lipid homeostasis of crustaceans by interacting with retinoid X receptor (RXR) and crustacean hyperglycemic hormone (CHH) signaling. Moreover, it can also interact with other nuclear receptors, disrupting methyl farnesoate and ecdysteroid signaling, thereby altering growth and sexual maturity, respectively. This compound also interferes in cytochrome P450 system disrupting steroid synthesis and reproduction. Crustaceans are also important fisheries worldwide, and its consumption can pose risks to human health. However, some questions remain unanswered. This mini review aims to update information about the effects of OTs on the metabolism, growth, and reproduction of crustaceans; to compare with known effects in mammals; and to point aspects that still needs to be addressed in future studies. Since both macrocrustaceans and microcrustaceans are good models to study the effects of sublethal TBT contamination, novel studies should be developed using multibiomarkers and omics technology

Effects of organotins on crustaceans : update and perspectives

Organotins (OTs) are considered some of the most toxic chemicals introduced into aquatic environments by anthropogenic activities. They are widely used for agricultural and industrial purposes and as antifouling additives on boat hull’s paints. Even though the use of OTs was banned in 2008, elevated levels of OTs can still be detected in aquatic environments. OTs’ deleterious effects upon wildlife and experimental animals are well documented and include endocrine disruption, immunotoxicity, neurotoxicity, genotoxicity, and metabolic dysfunction. Crustaceans are key members of zooplankton and benthic communities and have vital roles in food chains, so the endocrine-disrupting effects of tributyltin (TBT) on crustaceans can affect other organisms. TBT can disrupt carbohydrate and lipid homeostasis of crustaceans by interacting with retinoid X receptor (RXR) and crustacean hyperglycemic hormone (CHH) signaling. Moreover, it can also interact with other nuclear receptors, disrupting methyl farnesoate and ecdysteroid signaling, thereby altering growth and sexual maturity, respectively. This compound also interferes in cytochrome P450 system disrupting steroid synthesis and reproduction. Crustaceans are also important fisheries worldwide, and its consumption can pose risks to human health. However, some questions remain unanswered. This mini review aims to update information about the effects of OTs on the metabolism, growth, and reproduction of crustaceans; to compare with known effects in mammals; and to point aspects that still needs to be addressed in future studies. Since both macrocrustaceans and microcrustaceans are good models to study the effects of sublethal TBT contamination, novel studies should be developed using multibiomarkers and omics technology