Maternal protein restriction induce skeletal muscle changes without altering the MRFs MyoD and myogenin expression in offspring

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In utero protein restriction causes growth delay and alters sperm parameters in adult male rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Maternal undernutrition and the offspring kidney: from fetal to adult life

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Recovery of rat growth and lipid profiles in adult rats subjected to fetal protein malnutrition with a fructose-rich diet

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Larval competition for patchy resources in Chrysomya megacephala (Dipt., Calliphoridae): implications of the spatial distribution of immatures

In the present study, a single procedure was established to investigate the effect of the spatial distribution of immatures in patchy resources, on the outcome of larval competition for food. in experimental populations of Chrysomya megacephala. A theoretical model of intraspecific competition was extended and applied to experimental data on survival to adulthood for 20 larval densities, to obtain the theoretical mean number of individuals that will survive, considering a hypothetical previous random adult oviposition in a system of homogeneous patches. The survival curve obtained suggests that the larval competition for food in C. megacephala is of the scramble/exploitative type, which corroborates results from previous studies, although the latter did not consider the correlation between local and global abundances. The present model allows that experimental data could be perfectly applicable, and it incorporates fundamental assumptions about the spatial context of competition for patchy resources in blowflies, and may be applied to the optimization of mass rearing techniques and to the maintenance of insect colonies under experimental conditions.

Developmental changes in cold tolerance and ability to autoresuscitate from hypothermic respiratory arrest are not linked in rats and hamsters

In adult mammals, severe hypothermia leads to respiratory and cardiac arrest, followed by death. Neonatal rats and hamsters can survive much lower body temperatures and, upon artificial rewarming, spontaneously recover from respiratory arrest (autoresuscitate), typically suffering no long-term effects. To determine developmental and species differences in cold tolerance (defined here as the temperature of respiratory arrest) and its relation to the ability to autoresuscitate, we cooled neonatal and juvenile Sprague-Dawley rats and Syrian hamsters until respiration ceased, followed by rewarming. Ventilation and heartbeat were continuously monitored. In rats, cold tolerance did not change throughout development, however the ability to autoresuscitate from hypothermic respiratory arrest did (lost between postnatal days, P, 14 and 20), suggesting that the mechanisms for maintaining breathing at low temperatures was retained throughout development while those initiating breathing on rewarming were altered. Hamsters, however, showed increased cold tolerance until P26-28 and were able to autoresuscitate into adulthood (provided the heart kept beating throughout respiratory arrest). Also, hamsters were more cold tolerant than rats. We saw no evidence of gasping to initiate breathing following respiratory arrest, contributing to the hypothesis that hypothermic respiratory arrest does not lead to anoxia. (C) 2012 Elsevier B.V. All rights reserved.

Exposure to ethinylestradiol during prenatal development and postnatal supplementation with testosterone causes morphophysiological alterations in the prostate of male and female adult gerbils

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Differentiation of Leydig Cells in the Mongolian Gerbil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Prevalência de dislipidemia em indivíduos fisicamente ativos durante a infância, adolescência e idade adulta

FUNDAMENTO: A prevalência de dislipidemias vem aumentando em diversas partes do Brasil, porém não é claro ainda quanto de exercício físico é necessário para se obter efeitos benéficos sobre os níveis de lipoproteínas plasmáticas. OBJETIVO: O estudo analisou, em oito cidades do Estado de São Paulo, a associação entre a prática continuada de exercícios físicos ao longo da vida e a ocorrência de dislipidemia na idade adulta. MÉTODOS: Estudo transversal envolvendo 2.720 adultos, de ambos os sexos, residentes em oito cidades do Estado de São Paulo. Por meio de entrevista domiciliar, a presença de dislipidemias foi autorreferida e a prática de exercícios físicos foi analisada na infância (7-10 anos), na adolescência (11-17 anos) e na idade adulta (atividades de lazer). No tratamento estatístico, modelos multivariados foram criados com a regressão logística binária. RESULTADOS: A prevalência de dislipidemia foi de 12,2% (IC95%= 11,1%-13,5%) e não houve diferença entre as cidades (p = 0,443). Mulheres (p = 0,001) e obesos (p = 0,001) apresentaram maior taxa de dislipidemia. Exercício físico atual não se associou com a presença de dislipidemia ([> 180 minutos por semana] p = 0,165), porém, a prática de exercício físico, tanto na infância (p = 0,001) como na adolescência (p = 0,001), foi associada com menor ocorrência da doença. Adultos fisicamente ativos em todos os três momentos da vida apresentaram 65% menos chances de reportar dislipidemia (RC = 0,35 [0,15-0,78]). CONCLUSÃO: A prática continuada de exercícios físicos ao longo da vida foi associada com menor ocorrência de dislipidemia entre adultos do Estado de São Paulo.

Sexual behavior and fertility of male rats submitted to prolonged immobilization-induced stress

In order to investigate whether prolonged stress interferes with the onset of sexual behavior at puberty and with fertility at adulthood, prepubertal male Wistar rats (40 days of age) were immobilized 6 h a day for 15 days (up to early puberty) or for 60 days (until sexual maturity). Pubertal stressed rats showed a two-fold increase in the latency for the first mount (probably due to repeated aversive experience in which a change of environment was always followed by immobilization) and a 2.5-fold increase in the frequency of thrusting (indicative of enhanced sexual performance). The apparently stimulatory effect of prolonged stress on the onset of sexual behavior is discussed in terms of increased testosterone level and interference with the complex interchanges between the neurotransmitters/neuropeptides involved in the central control of male sexual activity. Adult stressed animals were mated with normal females, which became pregnant but exhibited a more than two-fold increase in both pre-implantation and post-implantation loss, probably due to a smaller rate of fertilization and/or fertilization with damaged spermatozoa.

Fertility of male adult rats submitted to forced swimming stress

We investigated whether stress interferes with fertility during adulthood. Male Wistar rats (weighing 220 g in the beginning of the experiment) were forced to swim for 3 min in water at 32ºC daily for 15 days. Stress was assessed by the hot-plate test after the last stressing session. To assess fertility, control and stressed males (N = 15 per group) were mated with sexually mature normal females. Males were sacrificed after copulation. Stress caused by forced swimming was demonstrated by a significant increase in the latency of the pain response in the hot-plate test (14.6 ± 1.25 s for control males vs 26.0 ± 1.53 s for stressed males, P = 0.0004). No changes were observed in body weight, testicular weight, seminal vesicle weight, ventral prostate weight or gross histological features of the testes of stressed males. Similarly, no changes were observed in fertility rate, measured by counting live fetuses in the uterus of normal females mated with control and stressed males; no dead or incompletely developed fetuses were observed in the uterus of either group. In contrast, there was a statistically significant decrease in spermatid production demonstrated by histometric evaluation (154.96 ± 5.41 vs 127.02 ± 3.95 spermatids per tubular section for control and stressed rats, respectively, P = 0.001). These data demonstrate that 15 days of forced swimming stress applied to adult male rats did not impair fertility, but significantly decreased spermatid production. This suggests that the effect of stress on fertility should not be assessed before at least the time required for one cycle of spermatogenesis.

On the development of the brown spider Loxosceles gaucho Gertsch (Araneae, Sicariidae): the nympho-imaginal period

Observations of the developmental biology of Loxosceles gaucho Gertsch, 1967, the brown spider of southeastern Brazil are scarce. The present study reports the method of individualized rearing of 18 populations of L. gaucho, kept in laboratory under varied diet conditions, and characterizes their nympho-imaginal period as well as factors related to their reproduction. Females built the first egg sac about 20 days after copulation and nymphs hatched 40 days after the laying date. Average offspring was 61.3 spiderlings and females usually built three to four successive egg sacs in a period of five to seven months. First nymphs initiated their predatory activity between the 5th and 8th days after hatching and the majority reached adulthood within six moults (range of five to eight) in approximately 15 to 17 months (male) and 15.5 to 18 months (female). The average sex ratio equaled 1.0:1.7 (male:female). The wide individual variability of this species intermoult intervals is herewith expressed by the intermoult rate, which was fairly uniform for both intra and interpopulations and gives a relevant aspect for a general idea of the life cycles of spiders.

Effects of maternal exposure to an aromatase inhibitor on sexual behaviour and neurochemical and endocrine aspects of adult male rat

The present study examined the effects of letrozole exposure during brain sexual differentiation on endocrine, behavioural and neurochemical parameters in male rat descendants. Pregnant female rats received 1 mg kg(-1) day(-1) letrozole or vehicle by oral gavage on gestational Days 21 and 22. Exposure to letrozole reduced anogenital distance in males on postnatal Day (PND) 22. At adulthood (PND 75), plasma testosterone levels and hypothalamic dopaminergic activity were increased, but sexual competence was impaired, because fewer successful sexual behaviours (mount, intromission and principally ejaculation) were observed. The impairment of reproductive function by prenatal exposure to an aromatase inhibitor reinforces the importance of adequate oestrogenic activity during perinatal sexual differentiation for complete masculinisation of the hypothalamus.

Prenatal testosterone supplementation alters puberty onset, aggressive behavior, and partner preference in adult male rats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Hypoactivity of the central dopaminergic system and autistic-like behavior induced by a single early prenatal exposure to lipopolysaccharide

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)