Transcapillary PO 2 Gradients in Contracting Muscles of Type I Diabetic Rats.

Objective: This study aimed to clarify the effect of Type I diabetes (DIA) on transcapillary PO ₂ gradients, which are oxygen-driving factors between the blood and the interstitium, in the contracting muscle of rats.
Methods: Wistar male rats were divided into the diabetic (streptozocin i.p.) and sham groups. Microvascular and interstitial PO ₂ were measured in the extensor digitorum longus muscle during electrical stimulation-induced muscle contraction, using the phosphorescence quenching method. Transcapillary PO ₂ gradient, ΔPO ₂ , was calculated as microvascular minus interstitial PO ₂ .
Results: Resting microvascular PO ₂ was higher in the diabetic group than in the sham group (6.3 ± 1.7 vs. 4.7 ± 0.9 mmHg, p < 0.05) and remained for 180 s. Interstitial PO ₂ from rest to muscle contraction did not differ between the groups. The ΔPO ₂ was higher in the diabetic group than in the sham group at rest and during muscle contraction (4.03 ± 1.42 vs. 2.46 ± 0.90 mmHg at rest; 3.67 ± 1.51 vs. 2.22 ± 0.65 mmHg during muscle contraction, p < 0.05). Marked muscle atrophy was observed in the diabetic group.
Conclusion: DIA increased microvascular and transcapillary PO ₂ gradients in the skeletal muscle. The enhanced PO ₂ gradients were maintained from rest to muscle contraction in diabetic muscle.
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