Experimental evidence of selective axonal regeneration in allogenic and isogenic Y-chambers

Studies on axonal regeneration in Y-chambers over the past decade have consistently provided evidence of preferential growth toward a distal nerve piece. However, these findings are in contrast to the observations by Weiss and Taylor (1944. J. Exp. Zool. 95: 233-257), indicating that in fresh aortic Y-chambers regenerating axons had no tendency to grow into a channel containing a distal nerve piece as compared to an open channel. The discrepancy between Weiss and Taylor's findings and those of later authors remains unexplained. In the present study we repeated the investigations by Weiss and Taylor, using both isogenic and allogenic aortic Y-chambers. In control groups the aorta graft was frozen and treated chemically to kill all cells and to deactivate possible growth factors of protein nature. In these groups preferential growth toward the distal nerve was pronounced although such specificity in growth was evident also in the nontreated types of aortic chambers. The findings do not support the results presented by Weiss and Taylor.