ABSTRACT
Pregnancy is considered a period of big variation to the maternal organism. Besides, the mother is due to stressing influences from the external environment that might intervene in health and mother-fetal wellbeing. Thus, mating in the experimental facility may avoid stress from handling and transporting pregnancy females, assuring full observation over pre and post gestational periods. However, to obtain pregnancy females can avoid loss of animals that cannot get pregnant and prevent acquiring males. This study aimed to determine if there are behavior changings caused by handling and transporting females obtained already pregnant by observing pre and postnatal periods: gestation, lactation, soundness of neonates and their development after weaning verifying alterations that could cause injury for litter growth. Animals were evaluated through neurobehavior tests and results were compared to those previously obtained in studies whose mating was performed in the experimental animal facility. In the handgrip reflex test, an increase in the experimental group of males and females was observed on the 4th day of observation and a decrease on the 8th day, in females. When comparing postural reflex, results didn’t show significant differences. In the results for negative geotaxia, no significant difference was observed among groups, as well as locomotion movement and general activity. Mother’s body weight during pregnancy didn’t present any significative difference for the experimental group related to control group. These results, put together, cannot allow stating significant influence in transporting females in the first stages of pregnancy in Wistar rats.
A gestação é considerada um período de grandes variações no organismo materno. Além disso, a mãe está sujeita às influências estressantes provindas do ambiente externo que podem interferir na saúde e no bem-estar materno-fetal. Assim, o acasalamento feito no próprio biotério de experimentação pode evitar o estresse da manipulação e do transporte da fêmea gestante, garantindo o acompanhamento total do período pré e pós-gestacional. Porém, adquirir fêmeas prenhes pode evitar perdas decorrentes de animais que não conseguem emprenhar e evitar a solicitação de machos. Este estudo buscou determinar se existem alterações comportamentais causadas pela manipulação e transporte em fêmeas adquiridas prenhez a partir do acompanhamento dos períodos pré e pós-natal: gestação, lactação, sanidade dos neonatos e seu desenvolvimento após o desmame para verificação de alterações que possam causar prejuízo no desenvolvimento dos filhotes. Os animais foram avaliados através da realização de testes neurocomportamentais e comparados a resultados obtidos anteriormente em estudos cujo acasalamento fora feito no próprio biotério de experimentação. No teste de reflexo de preensão palmar foi observado um aumento no tempo de realização no grupo experimental em machos e fêmeas no PN4 e diminuição no PN8 em fêmeas. Na comparação dos grupos no reflexo postural os resultados não demonstraram diferença significativa. Os resultados da geotaxia negativa, na comparação dos grupos, não evidenciou nenhuma diferença significativa, tampouco houve diferenças significativas para movimentos de locomoção e na atividade geral. O peso das mães durante o tempo de gestação não apresentou nenhuma diferença significativa do grupo experimental em relação ao grupo controle. Estes resultados, avaliados em conjunto, não nos permitem afirmar que houve uma influência significativa do transporte das fêmeas no estágio inicial da gestação de ratas Wistar.
ABSTRACT
Few data are available in the literature describing the long-term effects of envenoming in the perinatal period. In this study, the relationship between envenoming of lactating rats and possible behavioral changes in the mother and in her offspring were investigated. Lactating Wistar rats received a single dose of T. serrulatus crude venom on postnatal days 2 (V2), 10 (V10) or 16 (V16), and had their maternal behavior evaluated. The seizure threshold was evaluated in adulthood offspring. A decrease in maternal care during envenoming was observed in V2 and V10 groups. The retrieval behavior was absent in the V2 group, and a lower seizure threshold in the adult offspring of all groups was observed. During envenoming, mothers stayed away from their offspring for a relatively long time. Maternal deprivation during the early postnatal period is one of the most potent stressors for pups and could be responsible, at least in part, for the decrease in the convulsive threshold of the offspring since stress is pointed to as a risk factor for epileptogenesis. Furthermore, the scorpionic accident generates an intense immune response, and inflammation in neonates increases the susceptibility to seizures in adulthood. Therefore, maternal envenoming during lactation can have adverse effects on offspring in adulthood.
ABSTRACT
The pinealgland synthesizes melatonin exclusively at night, which gives melatonin the characteristic of a temporal synchronizer of the physiological systems. Melatonin is a regulator of insulin activities centrally and also peripherally and its synthesis is reduced in diabetes. Since monosodium glutamate (MSG) is often used to induce the type 2 diabetic and metabolic syndrome in animal models, the purpose of this work is to evaluate the potential effects of MSG given to neonates on the pineal melatonin synthesis in different agedmale and female rats. Wistar rats were subcutaneously injected with MSG (4mg/g/day) or saline solution (0.9%) from the second to eighth post-natal day. The circadian profiles both melatonin levels and AANAT activity were monitored at different ages. Body weight, naso-anal length, adipose tissues weight, GTT, ITT and serum insulin levels were also evaluated. Typical obesity with the neonatal MSG treatment was observed, indicated by a great increase in adipose depots without a concurrent increase in body weight. MSG treatment did not cause hyperglycemia or glucose intolerance, but induced insulin resistance. An increase of melatonin synthesis at ZT 15 with phase advance was observed in in some animals. The AANAT activity was positively parallel to the melatonin circadian profile. It seems that MSG causes hypothalamic obesity which may increase AANAT activity and melatonin production in pineal gland. These effects were not temporally correlated with insulin resistance and hyperinsulinemia indicating the hypothalamic lesions, particularly in arcuate nucleus induced by MSG in early age, as the principal cause of the increase in melatonin production.
ABSTRACT
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive decline in cognitive function. Intracerebroventricular injection of streptozotocin (icv-STZ) has been used as an experimental model of Sporadic AD (SAD) in rodents and represents a promising tool for etiopathogenic analysis and evaluation of new therapeutic proposals for AD. The icv-STZ model shows many aspects of SAD abnormalities, resulting in decreased brain glucose and energy metabolism, cognitive impairment, oxidative stress, neuronal loss, and amyloid angiopathy. Royal jelly (RJ), a substance produced by worker honeybees of the Apis mellifera species, has been popularly used for more than 30 years in areas related to health eating and natural medicine. Researches indicate that RJ has a several pharmacological activities, including neuroprotective and improvement of cognitive function. The objective of this study was to investigate the effects of oral treatment with royal jelly during 2 weeks in Wistar rats submitted to icv-STZ on a working memory and neuroprotection, as evaluated by neurogenesis, neurodegeneration and oxidative stress. In this study, icv-STZ injection induced deleterious effects in the hippocampus, associated with cognitive impairments, and developed marked neurodegeneration, besides the reduction of neurogenesis and increased oxidative stress. On the other hand, RJ long-term oral administration induced beneficial effects in animals injured by icv-STZ injection, increasing retention time for working spatial memory, reducing neurodegeneration and oxidative stress level and increasing the proliferation of new neurons in the hippocampus. Thus, RJ promotes beneficial effects on cognitive functions and exhibits a neuroprotective action in the STZ experimental model of SAD.
