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Fig. 5
Actinotrichia defects in 72hpf, 7dpf pectoral and median fins of Tg(Inta11:NTR) following metronidazole treatment.
Collagen II Immunostaining of (A-F, M-R) pectoral and (G-L, S-X) median fins of Inta11: NTR + MTZ and Inta11: NTR–MTZ control larvae at 72hpf and 7dpf. At 72hpf, and 7dpf untreated larvae show rigid, parallel actinotrichia throughout the pectoral and median fin fold (A, C, G, I, M, O, S, U), with DAPI staining revealing proper fin fold mesenchymal cell migration (Yellow arrow) (B, H, N, T). Note the fin fold mesenchyme elongate along the proximal distal axis, aligning with the actinotrichia (Yellow arrow) (B-C, H-I, N-O, T-U). At 72hpf, and 7dpf, actinotrichia of MTZ-treated larvae are unable to remain rigid and bend within the fin fold (Purple arrow) (D, F, J, L, O, R, V, X). This correlates with fin fold collapse. The actinotrichia are unable to remain parallel to one another, creating gaps within the fin fold (D, F, J, L, O, R, V, X). Note the apparent unbundling of Collagen II stained strands at 72hpf (Purple arrow) (D, J). At 72hpf, DAPI staining reveals fin fold mesenchyme cluster next to the pectoral fin endoskeletal disc and the trunk region proximal to the median fin fold (Teal arrow) (E, K), having failed to migrate correctly. At 7dpf, surviving fin fold mesenchyme fails to migrate correctly (Teal arrow) (Q, W). In the pectoral fin, migration is restricted to the central region of the fin fold (Teal arrow) (Q) and in both the pectoral and median fin, these cells display elongation along various different axes, correlating with actinotrichia defects (Teal arrow) (P-R, V-X). Collagen II staining (A, D, G, J, M, P, S, V), DAPI (B, E, H, K, N, Q, T, W) and merged (C, F, I, L, O, R, U, X) images are presented. ED, Endoskeletal disc, T, Trunk Scale bars: 50μm in A-X.