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ORIGINAL RESEARCH article

Front. Physiol.

Sec. Environmental, Aviation and Space Physiology

Optimal Surgical Timing After High-Altitude De-Adaptation: Day-30 Post-Descent Marks Physiologic Recalibration and Improved Small Bowel Repair in Rats

Provisionally accepted
Yue  YizhiYue Yizhi1Wang  XiaohuaWang Xiaohua1Song  YaningSong Yaning1Sun  YiSun Yi1Chen  GaungyuChen Gaungyu1Feng  ZeFeng Ze1Dongfang  ZhaoDongfang Zhao2*
  • 1Chinese People's Liberation Army Western Theater General Hospital, Chengdu, China
  • 2Southwest Petroleum University, Chengdu, China

The final, formatted version of the article will be published soon.

Abstract Background: High-altitude de-adaptation following rapid transition from chronic hypoxia to normoxia has been associated with increased postoperative risk, yet its temporal physiological features and impact on intestinal repair remain poorly defined. Methods: Male Sprague–Dawley rats (n = 84) were exposed to simulated high altitude (5,000 m) for 90 days and then relocated to normoxia. Standardized small bowel rupture repair was performed at 1, 10, 20, 30, 40, 50, or 60 days after relocation. Hypoxia adaptation and reversibility were assessed using arterial oxygen saturation, hematological indices, hypoxia-responsive molecular markers, respiratory rate, body weight, and behavior. Postoperative outcomes were evaluated 10 days after surgery, including inflammatory cytokines, oxidative stress markers, immune cell infiltration, and histopathology. Results: Chronic hypoxia induced a stable hypoxia-adapted state characterized by reduced oxygen saturation, enhanced erythropoiesis, increased respiratory rate, and upregulation of intestinal HIF-1α and VEGF, all of which progressively normalized after return to normoxia and resolved by approximately 30 days. Perioperative survival did not differ among groups. In contrast, systemic inflammatory cytokines and lipid peroxidation peaked at day 1 post-relocation and declined to nadir levels by day 30. This period was marked by reduced macrophage infiltration, peak fibroblast density, and more organized granulation tissue and collagen deposition. Conclusions: The duration of high-altitude de-adaptation is closely associated with intestinal repair quality. Approximately 30 days of normoxic re-acclimation correspond to coordinated resolution of hypoxia-related physiological perturbations and optimized tissue repair, identifying a critical post-relocation window relevant to surgical timing after descent from high altitude. Keywords: High-altitude de-adaptation, intestinal repair, surgical timing, oxidative stress, inflammatory response

Keywords: High-altitude de-adaptation, Inflammatory Response, intestinal repair, Oxidative Stress, Surgical timing

Received: 08 Nov 2025; Accepted: 08 Jan 2026.

Copyright: © 2026 Yizhi, Xiaohua, Yaning, Yi, Gaungyu, Ze and Zhao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dongfang Zhao

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