Altered production of reproductive neuropeptides in rats subjected to chronic intermittent hypoxia.

Hypobaric hypoxia is a stressful condition known to decrease fertility both in humans and animals. However, the mechanism by which the hypothalamus-pituitary-gonad axis is altered remains unknown. The aim of the present study was to analyze the effects of chronic intermittent and continuous exposure to hypoxia on hypothalamic-pituitary-gonadal axis regulation in male rats.

Mandibular biomechanical behavior of rats submitted to chronic intermittent or continuous hypoxia and periodontitis.

Background: The aim of this study was to investigate the effects of exposure to continuous (CH) and intermittent (IH) hypoxia on biomechanical properties of the mandible and periodontal tissue of animals submitted to experimental periodontitis (EP) when applying loads in a hypoxic environment.

Methods: Adult female Wistar rats were exposed during 90 days to IH or CH (simulated high altitude of 4200 m above sea level). Fourteen days prior to the euthanasia, EP was induced to half of the animals of each group.

The Process of Acclimation to Chronic Hypoxia Leads to Submandibular Gland and Periodontal Alterations: An Insight on the Role of Inflammatory Mediators.

The exposition to hypoxia is a stressful stimulus, and the organism develops acclimation mechanisms to ensure homeostasis, but if this fails, it leads to the development of pathological processes. Considering the large number of people under hypoxic conditions, it is of utmost importance to study the mechanisms implicated in hypoxic acclimation in oral tissues and the possible alteration of some important inflammatory markers that regulate salivary and periodontal function. It is the aim of the present study to analyze submandibular (SMG) and periodontal status of animals chronically exposed to continuous (CCH) or intermittent (CIH) hypoxia in order to elucidate the underlying molecular mechanisms that may lead to hypoxic acclimation.

Deleterious effect of chronic continuous hypoxia on oral health.

Objective: To evaluate the effect of chronic continuous hypoxia (CCH) in alveolar bone and its correlation with the inflammatory markers which play a key role in the development of periodontitis.

Material And Methods: Wistar rats were exposed to CCH (600mbar, 3 months). Macroscopic and histological analyses of alveolar bone were performed, together with measurement of oxidative stress and inflammatory parameters in gums and submandibular glands (SMG).

Chronic lead poisoning magnifies bone detrimental effects in an ovariectomized rat model of postmenopausal osteoporosis.

Lead (Pb) is a persistent environmental contaminant that is mainly stored in bones being an important source of endogenous lead exposure during periods of increased bone resorption as occurs in menopause. As no evidence exists of which bone biomechanical properties are impaired in those elderly women who had been exposed to Pb during their lifetime, the aim of the present study is to discern whether chronic lead poisoning magnifies the deterioration of bone biology that occurs in later stages of life. We investigated the effect of Pb in the femora of ovariectomized (OVX) female Wistar rats who had been intoxicated with 1000 ppm of Pb acetate in drinking water for 8 months.

Lead intoxication under environmental hypoxia impairs oral health.

We have reported that chronic lead intoxication under hypoxic environment induces alveolar bone loss that can lead to periodontal damage with the subsequent loss of teeth. The aim of the present study was to assess the modification of oral inflammatory parameters involved in the pathogenesis of periodontitis in the same experimental model. In gingival tissue, hypoxia increased inducible nitric oxid synthase (iNOS) activity (p < .

Alveolar bone loss associated to periodontal disease in lead intoxicated rats under environmental hypoxia.

Previously reported studies from this laboratory revealed that rats chronically intoxicated with lead (Pb) under hypoxic conditions (HX) impaired growth parameters and induced damages on femoral and mandibular bones predisposing to fractures. We also described periodontal inflammatory processes under such experimental conditions. Periodontitis is characterised by inflammation of supporting tissues of the teeth that result in alveolar bone loss.

Lead bone toxicity in growing rats exposed to chronic intermittent hypoxia.

Lead chronic intoxication under hypoxic conditions revealed growth retardation in growing rats and damages on femoral and mandibular bones that predispose to fractures. These findings aimed us to investigate if bone material and geometric properties, bone mass in terms of histomorphometry or antioxidant capacity are also impaired in such experimental model. Combined treatments significantly reduced hemimandible cross sectional geometry and intrinsic stiffness (-16% and -34%); tibia and hemimandible bone volume (-45% and -40%) and growth plate cartilage thickness (-19%).

Effects of lead exposure on growth and bone biology in growing rats exposed to simulated high altitude.

The existence of children living at high altitude suffering from lead (Pb) poisoning prompted us to investigate the long term effects of this pollutant on growth and bone biology in growing rats maintained at simulated high altitude (SHA). Pb and hypoxia (HX) significantly reduced body weight (-9.4 % and -24 %; p < 0.