Figure 3.

Early excitability in the lumbar spinal cord. (A) The relative monosynaptic responses of the motor neurons recorded in the ventral root decreased with increasing frequencies of stimulation of the dorsal root in the four groups of pups from P5 to P6, compared to the reference level at stimulation at a frequency of 0.1 Hz (p < 0.0001). Lower reductions in the relative monosynaptic responses were noted for the LBW-vehicle group, compared to the sham-vehicle group, at all frequencies of stimulation after the reference one (0.1 Hz), which is indicative of lumbar network hyperexcitability. These responses in pups of the LBW-MSC group were significantly reduced, compared to pups in the LBW-vehicle group at all frequencies, which suggests a reduction of hyperexcitability in the lumbar spinal cord with MSC treatment. Sham-vehicle (n = 7), sham-MSC (n = 7), LBW-vehicle (n = 10), and LBW-MSC (n = 12). (B) Representative images of Western blot analysis of the monomeric and oligomeric forms from the total fraction of KCC2 in LBW pups treated using a vehicle or MSCs at P8. (C) Quantified expression levels of the monomeric (inactive) form of KCC2. There seemed to be decreases in LBW pups compared to pups in sham pups, but the differences were not significant. (D) Quantified expression levels of the oligomeric (active) form of KCC2. There were no significant differences among the groups. Sham-vehicle (n = 4), sham-MSC (n = 3), LBW-vehicle (n = 7), and LBW-MSC (n = 12). *p < 0.05, **p < 0.01. Mean ± standard deviation. KCC2, K⁺–Cl⁻ cotransporter type 2; LBW, low birth weight; MSC, mesenchymal stromal cell; P5, postnatal day 5.