Figure 1. Calpain inhibition alleviates early behavioral signs of spasticity in neonatal rats with SCI.

(A,B) Pictures of typical hindlimb motor response to tail pinching in sham-operated (A), n = 6 rats) and SCI rats (B), 5 d post-SCI, n = 8 rats). Lower and upper traces represent the pinch force and the evoked electromyographic (EMG) response of the triceps surae muscle, respectively. (C,D) Group means quantification of EMG responses. *p<0.05, ***p<0.001 comparing sham versus SCI groups; Mann-Whitney test. (E) Groups means quantification of twitches over a time period of 10 min obtained from sham-operated and SCI rats (5 d post-SCI) at rest on heating pad (~34.5°C). ***p<0.001 comparing sham versus SCI groups (n = 22 rats in both groups); Mann-Whitney test. (F) Time-course changes of twitches after acute i.p. administration (t = 0) of vehicle (black, n = 5 rats) or MDL28170 at 60 mg/kg (red, n = 5 rats) or MDL28170 at 120 mg/kg (green, n = 5 rats) in SCI neonatal rats (5 d post-SCI). *p<0.05, **p<0.01, ***p<0.001, repeated measures one-way ANOVA, Dunnett’s post-test. (G) Representative EMG responses of the triceps surae muscle to tail pinching in SCI neonatal rats (5 d post-SCI) 60 min after an acute i.p. administration of vehicle (black, n = 9 rats) or MDL28170 (red, 120 mg/kg, n = 6 rats). Lower traces represent the pinch force. Group means quantification of EMG responses on the right-hand side. *p<0.05; comparing vehicle-treated versus MDL28170-treated rats; Mann-Whitney test. Underlying numerical values can be found in the Figure 1—source data 1.

Figure 1—figure supplement 1. Calpain inhibition does not affect the number of twitches recorded in intact neonatal rats.

Time-course changes of twitches after acute i.p. administration (t = 0) of MDL28170 (120 mg/kg) in intact neonatal rats (4–5 d old; n = 6 rats). n.s. p>0.05, repeated measures one-way ANOVA, Dunnett’s post-test. Data are means ± SD. Underlying numerical values can be found in the Figure 1—figure supplement 1—source data 1.

Figure 1—video 1. Typical hindlimb motor movements to tail pinching in sham-operated neonatal rats.

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Figure 1—video 2. Typical hindlimb motor movements to tail pinching in spinal cord transected neonatal rats.

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Figure 1—video 3. Typical spontaneous tail and hindlimb movements in sham-operated neonatal rats.

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Figure 1—video 4. Typical spontaneous tail and hindlimb movements in spinal cord transected neonatal rats.

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