Gastrointestinal toxicity induced by microcystins

Figure 1 Chemical structure of microcystins.

Figure 2 Subcellular localization of MC-LR and MC-RR in Caco-2 cells, which was adapted from a reference[11]. A: Caco-2 cells were treated for four hours with concentrations of MC-LR or MC-RR ranging from 1-50 μmol/L; B: Caco-2 cells were treated for several time points with 20 μmol/L of MC-LR or MC-RR. The cellular localization of these toxins was detected using an anti-ADDA antibody and an Alexa fluor 488 secondary antibody. Nuclei were counterstained with DAPI. The symbols (−), (+), (++) and (+++) represent the relative importance of the staining localization into the cell. Scale bars: A: 20 μm; B: 10 μm. ND: Alexa fluor 488 staining not detected; LD: Low signal of Alexa fluor 488 staining; (+/−) low signal intensity; MC: Microcystin.

Figure 3 Histopathological and ultrastructural observations in the gastrointestinal tract of Tenca fish exposed to MCs. Adapted from a ref.[40]. H and E staining (A) and ultrastructural observations (B). A and B: Control groups; C and D: 25 mg of MC-LR/fish group; E and F: 55 mg of MC-LR/fish groups. Vacuolated enterocytes (star). Vacuolization of the endoplasmic reticulum (arrow). Pycnotic nuclei, vacuolated cytoplasm (E, circle). Total microvilli loss (F, circle).

Figure 4 Summarization of the damages of microcystins to the gastrointestinal tract and further challenges that need to be addressed. MCs: Microcystins.