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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Impact of ovariectomy and CO2 inhalation on microglia morphology in select brainstem and hypothalamic areas regulating breathing in female rats

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Author(s):
Marques, Danuzia A. [1] ; Gargaglioni, Luciane H. [2] ; Joseph, Vincent [1] ; Bretzner, Frederic [3] ; Bicego, Kenia C. [2] ; Fournier, Stephanie [1] ; Kinkead, Richard [1]
Total Authors: 7
Affiliation:
[1] Univ Laval, Ctr Rech Inst Univ Cardiol & Pneumol Quebec, Dept Pediat, Quebec City, PQ - Canada
[2] Sao Paulo State Univ, UNESP FCAV Jaboticabal, Dept Anim Morphol & Physiol, Jaboticabal, SP - Brazil
[3] Univ Laval, Ctr Rech CHU Quebec, Dept Psychiat & Neurosci, Quebec City, PQ - Canada
Total Affiliations: 3
Document type: Journal article
Source: Brain Research; v. 1756, APR 1 2021.
Web of Science Citations: 0
Abstract

The neural network that regulates breathing shows a significant sexual dimorphism. Ovarian hormones contribute to this distinction as, in rats, ovariectomy reduces the ventilatory response to CO2. Microglia are neuroimmune cells that are sensitive to neuroendocrine changes in their environment. When reacting to challenging conditions, these cells show changes in their morphology that reflect an augmented capacity for producing pro- and anti-inflammatory cytokines. Based on evidence suggesting that microglia contribute to sex-based differences in reflexive responses to hypercapnia, we hypothesized that ovariectomy and hypercapnia promote microglial reactivity in selected brain areas that regulate breathing. We used ionized calcium-bindingadapter molecule-1 (Iba1) immunolabeling to compare the density and morphology of microglia in the locus coeruleus (LC), the caudal medullary raphe, the caudal part of the nucleus of the tractus solitarius (cNTS), and the paraventricular nucleus of the hypothalamus (PVN). Tissue was obtained from SHAM (metaestrus) female rats or following ovariectomy. Rats were exposed to normocapnia or hypercapnia (5% CO2, 20 min). Ovariectomy and hypercapnia did not affect microglial density in any of the structures studied. Ovariectomy promoted a reactive phenotype in the cNTS and LC, as indicated by a larger morphological index. In these structures, hypercapnia had a relatively modest opposing effect; the medullary raphe or the PVN were not affected. We conclude that ovarian hormones attenuate microglial reactivity in CO2/H+ sensing structures. These data suggest that microglia may contribute to neurological diseases in which anomalies of respiratory control are associated with cyclic fluctuations of ovarian hormones or menopause. (AU)

FAPESP's process: 19/09469-8 - Effect of incubation temperature on chick metabolism, thermoregulation and chemosensitivity
Grantee:Luciane Helena Gargaglioni Batalhão
Support type: Regular Research Grants
FAPESP's process: 16/21730-5 - LOCATION OF MEMBRANE PROGESTERONE RECEPTOR BETA IN RESPIRATORY NEURONS OF THE BRAINSTEM OF MALES AND FEMALES RATS AND EFFECTS OF HYPOXIA
Grantee:Danuzia Ambrozio Marques
Support type: Scholarships abroad - Research Internship - Doctorate