Figure 6
(a) Logarithmic VRMS amplitude of Tibialis Anterior (TA) motor activity in response to 473 nm, 105 mW/mm2 transdermal illumination of the proximal tibia for 4 s at 5 Hz and 10 ms PW for rats injected with ChR2-only vs. those with ChR2-EYFP. (b) Logarithmic minimum transdermal illumination power needed to elicit transdermal EMG spikes from TA for ChR2-only and ChR2-EYFP rats: VRMS spike threshold set to 2.45 µV, which was empirically determined to be the max noise level of recordings. (c) Ipsilateral to contralateral side of injection muscle weight ratio at the time of euthanasia between Rag2−/− and ChR2-only rats for both the anterior (A.C.) and posterior compartment (P.C.) muscle groups, representing primarily the TA and Gastrocnemius muscles respectively (n = 9 for Rag2−/−, n = 9 for ChR2 only). ChR2-only rat #7 (which had maintained expression at time of euthanasia) was also shown separately and excluded from significance test (PA.C. = 7E-5, PP.C. = 0.06). (d) Normalized ELISA comparing plasma antibodies against ChR2(H134R)-EYFP for WT rats at normal and low dose, Rag2−/− rats at normal dose, and ChR2(H134R) WT rats without reporter (nChR2-EYFP = 4, nChR2-EYFP low = 4, nChR2 only = 3, nRag2−/− = 5). Only ChR2-only rats who had lost all transdermal and subcutaneous expression at the time of blood collection were included. Pleft = 0.002; Pcenter = 0.12; Pright = 0.006. (e) ChR2-EYFP+ axon counts as percentage of total axons in tibial nerve (t.n.) and peroneal nerve (c.p.n.) of tacrolimus and no reporter rats (nTacrolimus = 8, nNoReporter = 9): Pt.n. = 0.02; Pc.p.n. = 4E-3. Tacrolimus rats #3 and #7 (which had lost expression at time of euthanasia), and no reporter rat #7 (which maintained expression at time of euthanasia) were excluded. Sciatic nerve cross sections of representative no reporter rat labeled for ChR2 (green) and DAPI (blue). Scale barbottom = 200 µm, Scale bartop = 30 µm. (f) Number of DAPI+ cells on ipsilateral side compared to contralateral side of spinal cord expressed as a percentage increase for WT (n = 3), Rag2−/− (n = 3), placebo (n = 3), tacrolimus (n = 3), and no reporter rats (n = 5). PANOVA = 8E-3. Can reject the null using Fisher’s LSD at α = 0.01 for ** and α = 0.05 for *.
