Microvasculature of rat striated muscle after temporary ischemia.

The structure and distribution of the capillaries of the rat anterior tibial muscle were analyzed by electronmicroscopy and microangiography 2 h and 1, 4, 18, 45 and 90 days after temporary ischaemia for 1, 2, 3, 4 and 6 h. Degeneration of some capillaries was seen first after ischaemia for 3 h, more extensive degeneration after ischaemia for 4 h, and after ischaemia for 6 h all the capillaries were undergoing degeneration when analyzed 1 day after the ischemia. Capillaries with normal ultrastructure were seen 45 days after the ischaemia. When examined 18 and 45 days after 3-6 h of ischaemia the capillary density was increased by about twofold but it decreased thereafter. At 18th and 45th days after 3-6 h of ischaemia the endothelial fraction of the capillary area was increased and the luminal fraction decreased. Microangiography of the anterior tibial muscles demonstrate the increase in the capillarization 18 and 45 days after 3-6 h of ischaemia.