Table 2.

Percentage of Schwann cell apoptosis 24 and 72 hr after transection of P1 wild-type and p75-deficient sciatic nerves

Nerve24 hr after transection72 hr after transection
Wild-type (n = 3) Mean ± SD (%)p75-deficient (n = 3) Mean ± SD (%)Wild-type (n = 5) Mean ± SD (%)p75-deficient (n = 6) Mean ± SD (%)
Distal nerve stump1.72  ± 0.93*0.17  ± 0.03*0.30  ± 0.16**0.16  ± 0.06**
Proximal nerve stump0.14  ± 0.050.15  ± 0.030.17  ± 0.080.04  ± 0.02
Contralateral nerve0.21  ± 0.080.16  ± 0.060.16  ± 0.070.04  ± 0.05
  • P1 nerves from p75-deficient mice and wild-type littermates were transected and analyzed by TUNEL. Transection results in a 13-fold increase in apoptosis 24 hr after sciatic nerve transection in the distal nerve stump of wild-type animals. In comparison, there was a twofold increase in Schwann cell apoptosis occurring 72 hr after transection of wild-types, whereas no such increase is observed in the distal stump of p75-deficient nerves at either time point. No differences in Schwann cell apoptosis were observed in the proximal nerve stumps or in contralateral control nerves. Sciatic nerve sections were stained with Hoechst nuclear stain to identify Schwann cell nuclei: a minimum of 25,000 Schwann cells were counted for each condition. (*,**P ≤ 0.05; two-tailedt test.)