ISSN 2326-7275
International Journal of Anatomy and Physiology | Vol. 15, No. 11, November 2026 | pp. 163–171
DOI: 10.46882/2026/IJAP/001019
Research Article
Title: Histomorphometric and Vascular Remodeling of the Skeletal Muscle Interstitium in Response to Localized Chronic Hypoxia
Names of Authors: F. K. Gasser¹, L. A. Rossi²*
Authors’ Affiliations:
¹ Institute of Physiology, University of Zurich, Zurich, Switzerland.
² Department of Biomedical Sciences, University of Padova, Padova, Italy.
Abstract:
Chronic hypoxia triggers microenvironmental alterations within skeletal muscle tissues, driving structural adaptation of both muscle fibers and peripheral vascular beds. This study used histomorphometric methods to quantify the remodeling of the tibialis anterior muscle interstitium and capillary supply in mice exposed to chronic normobaric hypoxia. Twenty adult mice were divided into a Normoxia group (21% O²) and a Hypoxia group (10% O²) for 28 days (n = 10 per group). Muscle cross-sections were evaluated using immunohistochemistry against CD31 (endothelial marker) and type IV collagen (basement membrane marker). Hypoxia exposure resulted in a significant 18% reduction in the mean cross-sectional area of type IIb glycolytic fibers (p < 0.05), indicating selective metabolic muscle atrophy. However, interstitial capillary density increased significantly in the hypoxic group (1150 ± 85 capillaries/mm² vs. 820 ± 60 capillaries/mm² in normoxic controls; p < 0.01). The capillary-to-fiber ratio rose from 1.34 ± 0.09 to 1.78 ± 0.12. Histomorphometric analysis of the extracellular matrix revealed an increased interstitial collagen volume fraction (6.4% ± 0.8% vs. 3.2% ± 0.4%; p < 0.05), accompanied by thickening of the capillary basement membrane. These structural adjustments demonstrate that while chronic hypoxia limits myofibrillar volume, it promotes interstitial angiogenesis and extracellular matrix deposition, maintaining oxygen diffusion transport loops despite low ambient oxygen tension.
Keywords: Chronic hypoxia, Tibialis anterior, Capillary density, Histomorphometry, Interstitium.
Manuscript Timeline: Received: July 19, 2026; Revised: September 08, 2026; Accepted: October 12, 2026; Published: November 06, 2026.
Citation: Gasser FK, Rossi LA. Histomorphometric and Vascular Remodeling of the Skeletal Muscle Interstitium in Response to Localized Chronic Hypoxia. International Journal of Anatomy and Physiology. 2026; 15(11): 163–171. doi:10.46882/2026/IJAP/001019