Alterations in the Gill Filaments and Secondary Lamellae of Cirrhinus mrigala Exposed to “Nuvan,” an Organophosphorus Insecticide

Figure 2

Photomicrographs of cross-sections (H/E) (a, c, and e) and scanning electron micrographs (b, d, and f) of gills of C. mrigala exposed to 5 mg/L of “Nuvan.” (a) Epithelium of gill filament (arrows) and secondary lamellae (barred arrows) increase in thickness due to hypertrophy of the epithelial cells. Note enlarged blood spaces (arrow heads) between pillar cells (winged arrows) (12 h). Scale bar = 20 μm. (b) The free surfaces of the epithelial cells appear rounded and bulged at the surface (barred arrows). (12 h) Scale bar = 10 μm. (c) Apical ends of adjacent secondary lamellae appear fused (arrow). Epithelial cells in the epithelium of gill filaments and secondary lamellae are greatly hypertrophied and appear bulging (barred arrows) at the surface (1 d). Scale bar = 20 μm. (d) Epithelial cells in the epithelium of gill filaments and secondary lamellae appear bulged (barred arrows) at the surface (1 d). Scale bar = 10 μm. (e) Oedematous swellings in the epithelium covering the secondary lamellae (arrow heads) (3 d). Scale bar = 20 μm. (f) Uplifting and detachment of the epithelium of secondary lamellae (arrows). Note the fusion of the apical end of several adjacent secondary lamellae (asterisk) (3 d). Scale bar = 10 μm.

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