Defective neuromuscular transmission in the SOD1 G93A transgenic mouse improves after administration of human umbilical cord blood cells.

To assess the effect of human umbilical cord blood (hUCB) transplantation on neuromuscular transmission in SOD1(G93A) transgenic mice, we studied the probability of neuromuscular transmission (PNMT), a relevant physiological indicator of motor nerve function, in 3 SOD1(G93A) mice transplanted with hUCB and compared to PNMT in 4 SOD1(G93A) mice without cell transplantation and 3 non-mutant SOD1 transgenic mice. For preparations isolated from non-mutant SOD1 transgenic mice, PNMT was 0.93 and 0.84 during the first 5 s of 70 and 90 Hz trains, respectively. PNMT gradually declined to 0.77 and 0.42 at the end of the trains. In striking contrast, PNMT for preparations from non-treated mutant SOD1(G93A) mice was 0.52 and 0.36 in the first 5 s of 70 and 90 Hz trains, respectively (p<0.05). Treatment with hUCB significantly (p<0.05) improved PNMT in SOD1(G93A) preparations. That is, the initial 5 s PNMT was 0.88 and 0.68 for the 70 and 90 Hz stimuli, respectively. We concluded that hUCB transplantation significantly improved PNMT for muscles removed from SOD1(G93A) mice. Testing PNMT in the SOD1(G93A) mouse model could be used as a simple in vitro protocol to detect a positive cellular response to therapeutic interventions in ALS.