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Fig. 4
Acute hyperglycemia affects the integrity of the perineurium. A: in control ins:NTR;Tg(nkx2.2a:megfp) fish 7 days postfertilization (dpf), zonula occludens (ZO)-1+ tight junctions are apparent along the motor nerve (A′′, arrow), indicated by their alignment with the perineurium (A′, asterisk). NTR, nitroreductase; megfp, monomeric enhanced green fluorescent protein. B: treatment of 5-dpf ins:NTR;Tg(nkx2.2a:megfp) fish for 2 days in 10 mM metronidazole (MTZ) leads to noticeably absent or attenuated ZO-1+ tight junctions (B′′, arrow), even when the perineurium is present (B′, asterisk). Note immaturity of the nkx2.2a+ perineurial cells (B′, asterisk). SC, spinal cord; pMN, motor neural progenitor domain. Scale bar = 50 μm. C: intensity of ZO-1 fluorescence was significantly lower in MTZ-treated than control fish. au, Arbitrary units. ****P < 0.0001.