Area and Environmental Lighting

2019 ◽  
pp. 303-344
Author(s):  
Vitor Sarri ◽  
Beatriz Ferrari ◽  
Larissa Magalhães ◽  
Paula Rodrigues ◽  
Almir Rezende ◽  
...  

Objective The aim of this study is to evaluate whether exposure to different environmental lighting conditions affects the reproductive parameters of pregnant mice and the development of their offspring. Methods Fifteen pregnant albino mice were divided into three groups: light/dark, light, and dark. The animals were euthanized on day 18 of pregnancy following the Brazilian Good Practice Guide for Euthanasia of Animals. Maternal and fetal specimens were measured and collected for histological evaluation. Analysis of variance (ANOVA) test was used for comparison of the groups considering p ≤ 0.05 to be statistically significant. Results There was no significant difference in the maternal variables between the three groups. Regarding fetal variables, significant differences were observed in the anthropometric measures between the groups exposed to different environmental lighting conditions, with the highest mean values in the light group. The histological evaluation showed the same structural pattern of the placenta in all groups, which was within the normal range. However, evaluation of the uterus revealed a discrete to moderate number of endometrial glands in the light/dark and light groups, which were poorly developed in most animals. In the fetuses, pulmonary analysis revealed morphological features consistent with the transition from the canalicular to the saccular phase in all groups. Conclusion Exposure to different environmental lighting conditions had no influence on the reproductive parameters of female mice, while the offspring of mothers exposed to light for 24 hours exhibited better morphometric features.


Author(s):  
Frances M. Baines ◽  
Lara M. Cusack

1986 ◽  
Vol 250 (2) ◽  
pp. R199-R206 ◽  
Author(s):  
J. L. Blank ◽  
C. Desjardins

Neuroendocrine responses were evaluated in an outbred population of deer mice (Peromyscus maniculatus nebrascensis) after exposure to an inhibitory photoperiod (8:16 light-dark) for 10 wk. Deer mice were chosen as an animal model for this study because they are typical of naturally selected species that rely on environmental factors to signal the onset or cessation of annual reproductive effort. Short photoperiods induced multiple neuroendocrine adjustments as judged by three types of spermatogenic responses: normal, intermediate, and azoospermic individuals. Plasma concentrations of luteinizing hormone and testosterone coincided with gradations in spermatogenic activity. In contrast, plasma concentrations of follicle-stimulating hormone were unaffected. Prolactin secretion was lowered in all mice exposed to short day lengths, regardless of sperm count. These results demonstrate that short photoperiods engage at least three types of neuroendocrine adjustments: 1) a suppression in luteinizing hormone and testosterone secretion accompanying spermatogenic arrest, 2) a reduction in prolactin secretion independent of changes in testicular function, and 3) a null response in gonadotrophic hormone secretion in which spermatogenesis is unimpaired by short day lengths. The neuroendocrine subsets identified in this model provide new evidence that photic cues induce three types of adjustments in pituitary-testicular function. These subsets are readily identified, and they can be easily exploited to dissect and manipulate the suite of neural, endocrine, and metabolic adaptations triggered by environmental lighting among mammals with annual reproductive strategies.


2020 ◽  
Vol 37 (8) ◽  
pp. 1201-1206
Author(s):  
A. Wieduwilt ◽  
E. A. Alsat ◽  
J. Blickwedel ◽  
B. Strizek ◽  
C. Di Battista ◽  
...  

2012 ◽  
Vol 54 (2) ◽  
pp. 162-169 ◽  
Author(s):  
Marina Marçola ◽  
Sanseray da Silveira Cruz-Machado ◽  
Pedro Augusto Carlos Magno Fernandes ◽  
Alex Willian Arantes Monteiro ◽  
Regina P. Markus ◽  
...  

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