[Changes of capillarity and blood flow of skeletal muscle in rat during acclimatization to hypoxia].

AIM

To study the changes of capillary density and blood flow of skeletal muscle in rat during acclimatization to hypoxia.

METHODS

Myosin-ATPase histochemistry was used to assay the size and capillarity of skeletal muscle. Biomicrospheres method was used to determine blood flow in the rats at 5-, 15-or 30-day hypobaric hypoxic exposure (simulated 5 000 m altitude).

RESULTS

It was found that cross-sectional area of skeletal muscle fibers (including type I and type II) were decreased during acclimatization to hypoxia. Capillary density (CD) was increased in 15-day and 30-day groups but the capillary/fiber ratio (C/F) remained unchanged among all of the groups observed. There was no obvious difference in blood flow between hypoxic rats and control rats.

CONCLUSION

Capillary neoformation does not occur in skeletal muscle of rat during acclimatization to hypobaric hypoxia. Increased capillary density due to atrophy of skeletal muscle fibre might benefit oxygen delivery at high altitude.