THE VASCULAR-RESPONSE TO NERVE TRANSECTION - NEOVASCULARIZATION IN THE SILICONE NERVE REGENERATION CHAMBER

The rat sciatic nerve regeneration chamber was used to study the spati al and temporal response of the endoneurial vasculature during regener ation. Proximal and distal stumps of a transected rat sciatic nerve we re placed in opposite ends of a silicone tube and allowed to regenerat e for periods of 2, 3, 4 or 52 weeks after the surgery. Serial, transv erse sections of nerve were studied at each time-point to quantitate t he number of vessels, capillary density and the vessel luminal perimet er per nerve area. The results indicate that the vascular growth relat ive to the existing tissue in the chamber increases to a peak beyond n ormal levels and later decreases to values associated with control tis sue. While this growth occurred from both the proximal and distal stum ps, it appeared predominately as a traveling wave in the proximal-dist al direction preceding the major thrust of neuritic outgrowth from the proximal stump. Morphologic measurements of angiogenesis were paralle led in other animals by measurements of nerve blood flow using laser D oppler flometry at corresponding time-points. These data differ somewh at from previous reports of angiogenesis following nerve crush injury and are useful in formulating a general mathematical model of regenera tion in the peripheral nervous system.