Alterations in the circadian cycle are known to cause physiological disorders in the hypothalamic–pituitary–adrenal and the hypothalamic–pituitary–gonadal axes in adult individuals. Therefore, the present study aimed to evaluate whether exposure of pregnant rats to constant light can alter the reproductive system development of male offspring. The dams were divided into two groups: a light–dark group (LD), in which pregnant rats were exposed to an LD photoperiod (12 h/12 h) and a light–light (LL) group, in which pregnant rats were exposed to a photoperiod of constant light during the gestation period. After birth, offspring from both groups remained in the normal LD photoperiod (12 h/12 h) until adulthood. One male of each litter was selected and, at adulthood (postnatal day (PND) 90), the trunk blood was collected to measure plasma testosterone levels, testes and epididymis for sperm count, oxidative stress and histopathological analyses, and the spermatozoa from the vas deferens to perform the morphological and motility analyses. Results showed that a photoperiod of constant light caused a decrease in testosterone levels, epididymal weight and sperm count in the epididymis, seminiferous tubule diameter, Sertoli cell number, and normal spermatozoa number. Histopathological damage was also observed in the testes, and stereological alterations, in the LL group. In conclusion, exposure to constant light during the gestational period impairs the reproductive system of male offspring in adulthood.

It was our objective to analyse the effects of resistance exercise (climbing steps), which was started in the acute phase, on the histomorphometry and the expression of aquaporin 1 (AQP1) in the soleus muscle after sciatic nerve injury in Wistar rats. Twenty-four adult rats were randomly divided into the following four groups, containing six animals each: control (G1); exercise (G2); injury (G3); and exercise with injury (G4). Three days after the compression of the sciatic nerve, the animals in G2 and G4 were submitted to resistance exercise for 21 non-consecutives days. The exercise was conducted in two series of 10 consecutive ascents of the ladder, with an additional weight of 100g and with an interval of 60 seconds between sets for rest. After this period, the animals were sacrificed, and the soleus muscle was processed. The number of blood capillaries in G3 was 65.7% and 76.86% higher when compared with the G2 and G4, respectively. The morphological analysis revealed muscle damage in G3, hypertrophy in G2 and significant improvement in the muscle in G4. The AQP1 was immunolocalized in the endothelium of blood capillaries present in the muscle fibres, with different expressions in the groups. Resistance exercise initiated in the acute phase was an effective therapeutic modality in the recovery of morphological aspects in the soleus muscle after denervation.

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Introduction: It has been suggested that maternal exposure to constant light during the gestational period could be considered as a chronic stressor, impairing offspring development by interfering in neuroendocrine and behavior responses.Objective: This study aimed to evaluate whether maternal exposure to continuous light during pregnancy affects the adult reproductive system in the female offspring. Materials and Methods: Pregnant Wistar rats were allocated into light-dark (LD) group, exposed to light and dark photoperiod during gestation, and the light-light (LL) group, exposed to a photoperiod of constant light during gestation. After birth, pups were maintained under normal light-dark photoperiod until adulthood. At postnatal day 90, blood was collected from the female offspring, to analyze plasma luteinizing hormone (LH) and progesterone levels, and the uterus and ovaries were harvested for morphometric, histological, and oxidative stress evaluations.Results and Discussion: Female exposure to continuous light during the intrauterine period resulted in the adult reduction of LH and increased progesterone plasma levels, and uterine injuries a higher number of endometrial

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