Transcapillary PO 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 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 were measured in the extensor digitorum longus muscle during electrical stimulation-induced muscle contraction, using the phosphorescence quenching method. Transcapillary PO gradient, ΔPO, was calculated as microvascular minus interstitial PO.

Results: Resting microvascular PO 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 from rest to muscle contraction did not differ between the groups. The ΔPO 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 gradients in the skeletal muscle. The enhanced PO gradients were maintained from rest to muscle contraction in diabetic muscle.