Table 1.

Neuregulin prevents apoptosis in P1 sciatic nerves axotomized for 1 d

Treatment	% TUNEL-positive nuclei
Treatment	Transected (left) side	Untransected (right) side
Transection, no neuregulin	9.44% ± 3.15	1.66% ± 0.28
Transection, plus neuregulin	0.72% ± 0.24^1_a	0.97% ± 0.23^b
No transection, no neuregulin	1.68% ± 0.54	2.40% ± 0.41
No transection, plus neuregulin	0.38% ± 0.23^1_c	1.68% ± 0.39^d

Newborn rats were divided into four treatment groups, three animals per group (see Materials and Methods). One day after transection, the distal stumps from transected nerves, the corresponding segment from unlesioned nerves, and the contralateral nerves were removed and processed for the TUNEL assay. TUNEL-positive nuclei were counted, and their percentage of the total was calculated (see Materials and Methods). The % TUNEL-positive nuclei in the left and right sciatic nerves from animals that received neuregulin were compared with those in animals that received vehicle alone by a paired, two-tailed t test.
↵F1_a The number of apoptotic cells in transected nerves from animals that received neuregulin was significantly less than that in transected nerves from animals that received vehicle alone (p < 0.0001).
^b,dAlthough neuregulin reduced the percentage of TUNEL-positive cells in the contralateral leg in both the transected and the nontransected animals, this reduction did not achieve statistical significance in either group.
↵F1_c The number of apoptotic cells in nontransected nerves from animals that received neuregulin was significantaly less than that in nontransected nerves from animals that received vehicle alone (p < 0.05).