Skin perfusion changes after sciatic nerve transection in the rat

Laser Doppler flowmetry was used as a method of measurement of skin blood flow perfusion in an experimental rat model of peripheral nerve section. The common sciatic nerve was microsurgically approached and cleanly severed (sciatic transection group). Contralateral nerves were approached but not injured (sham procedure). All paws were studied before any surgical procedure (controls) and immediately, 24 hours, 11 and 25 days after surgery. In each experiment, the skin perfusion was measured in the plantar surface of the hind paw, both in baseline conditions and after a heating test, where skin temperature around flowmeter probe reached 42 degrees C. Sham operated paws showed no differences from control unoperated paws. The heating test produced an increase in skin perfusion that ranged between 70% and 80% in sham and normal paws. Sciatic nerve section produces an immediate increase of 36.7% in blood flow with an additional increase of 27.5% after heating. In the following studies, on days 1, 11 and 25 baseline skin perfusion showed no changes in relation to preoperative values and heating induced only a small increase in perfusion.