Postural, morphological and swim defects in Mn-exposed zebrafish larvae. (A) Scheme representing the treatment protocol. (B) Control 5-dpf larva showing a normal swim bladder (blue arrow). (C) Mn-treated larvae showing an underdeveloped swim bladder. (D) Body position and morphology of free-swimming larvae: (i) control, (ii) Mn-treated and (iii) recovered larvae. Curvature of the spine (green arrow) and sideways floating (red arrow) were observed upon Mn exposure (middle panel). (E) Percentage survival for larvae treated for 24 (blue) or 48 hours (red) with Mn. When larvae were treated with 2 mM MnCl2 for 48 hours, 50% survival was observed (n=20, six batches). (F) The percentage of live larvae that exhibited spontaneous (circles) and stimulated (triangles) circular swimming patterns (CP) at different levels of Mn exposure. Spontaneous CP completely recovers after removal from Mn-containing medium, whereas ‘on-tap’ CP partially recovers. Statistical analyses were performed by using chi-square test to compare recovered with Mn-treated larvae (n=20, three batches). (G) The percentage of live larvae that demonstrated stimulated CP upon 48 hours of exposure to different metal ions: MnCl2 (blue), CaCl2 (green), NaCl (red) and MgCl2 (purple). Error bars in the plots represent s.e.m.
|
