scholarly journals Oxygen Enrichment Ameliorates Cardiorespiratory Alterations Induced by Chronic High-Altitude Hypoxia in Rats

2021 ◽  
Vol 11 ◽  
Author(s):  
Xi Shao ◽  
Xu Dong ◽  
Jing Cai ◽  
Chi Tang ◽  
Kangning Xie ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Right Ventricular ◽  
High Altitude ◽  
Collagen Type ◽  
Oxygen Enrichment ◽  
Male Rats ◽  
Type I ◽  
Converting Enzyme ◽  
Altitude Hypoxia ◽  
High Altitude Hypoxia

Chronic high-altitude hypoxia (HAH) results in compensatory pathological adaptations, especially in the cardiorespiratory system. The oxygen enrichment technology can provide long-lasting oxygen supply and minimize oxygen toxicity, which has proven to be effective to increase oxygen saturation, decrease heart rate, and improve human exercise performance after ascending to high altitudes. Nevertheless, it remains unknown whether oxygen enrichment can resist chronic HAH-induced cardiorespiratory alterations. Thirty-six male rats were equally assigned to the normal control (NC), HAH, and HAH with oxygen enrichment (HAHO) groups. The HAH and HAHO rats were housed in a hypobaric hypoxia chamber equivalent to 5,000 m for 4 weeks. The HAHO rats were exposed to oxygen-enriched air for 8 h/day. We found that oxygen enrichment mitigated the augmented skin blood flow and improved the locomotor activity of HAH-exposed rats. Oxygen enrichment inhibited HAH-induced increase in the production of red blood cells (RBCs). The hemodynamic results showed that oxygen enrichment decreased right ventricular systolic pressure (RVSP) and mean pulmonary artery pressure (mPAP) in HAH-exposed rats. HAH-associated right ventricular hypertrophy and cardiomyocyte enlargement were ameliorated by oxygen enrichment. Oxygen enrichment inhibited HAH-induced excessive expression of cytokines associated with cardiac hypertrophy and myocardial fibrosis [angiotensin-converting enzyme (ACE)/angiotensin-converting enzyme 2 (ACE2), angiotensin II (Ang II), collagen type I alpha 1 (Col1α1), collagen type III alpha 1 (Col3α1), and hydroxyproline] in the right ventricle (RV). Oxygen enrichment inhibited medial thickening, stenosis and fibrosis of pulmonary arterioles, and cytokine expression related with fibrosis (Col1α1, Col3α1, and hydroxyproline) and pulmonary vasoconstriction [endothelin-1(ET-1)] in HAH-exposed rats. This study represents the first effort testing the efficacy of the oxygen enrichment technique on cardiopulmonary structure and function in chronic HAH animals, and we found oxygen enrichment has the capability of ameliorating chronic HAH-induced cardiopulmonary alterations.

Reversibility of electrophysiological changes induced by chronic high-altitude hypoxia in adult rat heart

2002 ◽  
Vol 282 (4) ◽  
pp. H1452-H1460 ◽  
Author(s):  
C. Chouabe ◽  
J. Amsellem ◽  
L. Espinosa ◽  
P. Ribaux ◽  
S. Blaineau ◽  
...  
Keyword(s):  
Right Ventricular ◽  
High Altitude ◽  
Current Density ◽  
Ventricular Hypertrophy ◽  
Right Ventricular Hypertrophy ◽  
Heart Weight ◽  
Altitude Hypoxia ◽  
Altitude Exposure ◽  
High Altitude Hypoxia ◽  
The Right

Recent studies indicate that regression of left ventricular hypertrophy normalizes membrane ionic current abnormalities. This work was designed to determine whether regression of right ventricular hypertrophy induced by permanent high-altitude exposure (4,500 m, 20 days) in adult rats also normalizes changes of ventricular myocyte electrophysiology. According to the current data, prolonged action potential, decreased transient outward current density, and increased inward sodium/calcium exchange current density normalized 20 days after the end of altitude exposure, whereas right ventricular hypertrophy evidenced by both the right ventricular weight-to-heart weight ratio and the right ventricular free wall thickness measurement normalized 40 days after the end of altitude exposure. This morphological normalization occurred at both the level of muscular tissue, as shown by the decrease toward control values of some myocyte parameters (perimeter, capacitance, and width), and the level of the interstitial collagenous connective tissue. In the chronic high-altitude hypoxia model, the regression of right ventricular hypertrophy would not be a prerequisite for normalization of ventricular electrophysiological abnormalities.

scholarly journals Properties of a bovine collagen type I membrane for guided bone regeneration applications

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 210-221
Author(s):  
Igor S. Brum ◽  
Carlos N. Elias ◽  
Jorge J. de Carvalho ◽  
Jorge L. S. Pires ◽  
Mario J. S. Pereira ◽  
...  
Keyword(s):  
Bone Regeneration ◽  
Collagen Type ◽  
Mechanical Stability ◽  
Collagen Type I ◽  
Guided Bone Regeneration ◽  
Bone Volume ◽  
Male Rats ◽  
Toxicity Tests ◽  
Type I

Abstract Dental implant treatment requires an available bone volume in the implantation site to ensure the implant’s mechanical stability. When the bone volume is insufficient, one must resort to surgical means such as guided bone regeneration (GBR). In GBR surgery, bone grafts and membranes are used. The objective of this work is to manufacture and characterize the in vitro and in vivo properties of resorbable collagen type I membranes (Green Membrane®) for GBR. Membrane surface morphology was characterized by SEM and roughness was measured using an interferometric noncontact 3D system. In vivo skin sensitization and toxicity tests have been performed on Wistar rats. Bone defects were prepared in 24 adult male rats, filled with biomaterials (Blue Bone® and Bio Oss®) and covered with collagen membranes to maintain the mechanical stability of the site for bone regeneration. The incisions were closed with simple stitches; and 60 days after the surgery, the animals were euthanized. Results showed that the analyzed membrane was homogeneous, with collagen fiber webs and open pores. It had no sign of cytotoxicity and the cells at the insertion site showed no bone morphological changes. There was no tissue reaction and no statistical difference between Blue Bone® and Bio Oss® groups. The proposed membrane has no cytotoxicity and displays a biocompatibility profile that makes it suitable for GBR.

scholarly journals Integrative plasma proteomic and microRNA analysis of Jersey cattle in response to high-altitude hypoxia

2019 ◽  
Vol 102 (5) ◽  
pp. 4606-4618 ◽  
Author(s):  
Zhiwei Kong ◽  
Chuanshe Zhou ◽  
Bin Li ◽  
Jinzhen Jiao ◽  
Liang Chen ◽  
...  
Keyword(s):  
High Altitude ◽  
Altitude Hypoxia ◽  
Jersey Cattle ◽  
High Altitude Hypoxia
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