Fig. 4

Distinct cold tolerance in wild-type and gluk2^−/− zebrafish under the cooling scheme. (A) The changes in the body equilibrium of wild-type and gluk2^−/− zebrafish over time at 8 °C. (B) The percent survival of wild-type and gluk2^−/− zebrafish at 8 °C from 0 h to 5 h. (C) TUNEL assays in the gills of wild-type and genotypes, indicating a more serious apoptosis in gluk2^−/− mutant than in wild-type at the same cold temperature. Scale bar are 100 μm and 25 μm. (D) Comparison of apoptotic cell populations in the gills of wild-type and gluk2^−/− zebrafish over time at 8 °C. Values plotted are means ± SEM, * p < 0.05, ** p < 0.01, *** p < 0.001, compared with control, and are based on at least three biological replicates, with each replicate having at least 3 individuals at each time point.