COLD-INDUCED PERTURBATION OF CUTANEOUS BLOOD-FLOW IN THE RAT TAIL - AMODEL OF NONFREEZING COLD INJURY

Cold-induced alteration of cutaneous blood flow, measured with laser-D oppler flowmetry, was studied in a rat tail model of nonfreezing cold injury (NFCI). The NFCI-inducing condition consisted of prolonged tail immersion in 1 degrees water. Before exposure to the injury condition , tail blood flow (laser Doppler flux) during brief 3 degrees immersio n showed cold-induced cycles of vasoconstriction followed by cold-indu ced vasodilation (CIVD). Tail temperature exhibited cyclic patterns si milar to blood flow in response to cold water immersion. Cold exposure s to 1 degrees for 1 or 3 hr induced no systematic change; however, co ld exposures of 6 or 9 hr induced profound and long-lasting blood flow and temperature deviations. Following the cold injury condition, CIVD was completely absent and remained absent for several weeks, suggesti ng that CIVD loss is an important component in development of NFCI. Co ld-induced disturbances of cutaneous blood how in the rat tail consist ed of a sequence of distinctive stages analogous to those described in human NFCI. These stages were evidenced initially by several days of reduced blood flow and thermal sensitivity, followed in a week by a hy peremia stage, and later by enhanced vascular and thermal sensitivity. The cutaneous blood flow alterations and sequence of variations follo wing prolonged cold exposure suggest that the rat tail may be a valid model of human NFCI. (C) 1994 Academic Press, Inc.