Figure 1.
Histopathological lesions of rat hearts heat-stressed in vivo.
H&E staining, scale bar = 10 µm. (a) No obvious pathological changes were observed in control rats. In heat-stressed rat hearts, the following were observed at the indicated time points: (b) 20 min, acute granular degeneration (▴) with enlargement of heart cells(♦); (c) 40 min, swollen myocardial cells with reduced nuclei and cloudy cytoplasm (→♦); (d) 60 min, enlarged myocardial cells with acute granular degeneration (▴), accompanied by bleeding (▾); (e) 80 min, myocardial cells with cloudy cytoplasm and karyopyknosis (→); (f) 100 min, loss of defined nuclei (←) in enlarged myocardial cells. (g) In hearts of dead rats at 80 min of heat stress, pathological lesions, characterized by disordered arrangement of cells and loss of striations, along with karyopyknosis (→) and loss of nuclear definition (←), were observed. (h) In hearts of dead rats at 100 min of heat stress, pathological lesions were observed, characterized by karyopyknosis (→) and granular degeneration (▴), accompanied by bleeding (▾).
Figure 2.
Cytopathological lesions of H9C2 cells heat-stressed in vitro.
H&E staining, scale bar = 10 µm. (a) No obvious pathological changes were observed in control H9C2 cells. In heat-stressed H9C2 cells, the following were observed at the indicated time points: (b) 20 min, acute degeneration characterized by enlarged cell size (▴); (c) 40 min, light and clear pink granulation (▾) in the cytoplasm and karyopyknosis (→) was observed; (d) 60 min, cloudy cytoplasm (▴). (e) 80 min, enlarged cell size (▴) and intracellular granules (▾); (f) 100 min, acute granular degeneration characterized by numerous pink granules (▾) and enlarged cell size (▴).
Figure 3.
Localization of αB-crystallin in rat heart tissue before and after heat stress in vivo.
Immunohistochemical staining, scale bar = 10 µm, αB-crystallin (brown color, DAB). (a) Positive αB-crystallin signals were localized in the cytoplasm of non-stressed rat heart cells. In heat-stressed rat hearts, the following were observed at the indicated time points: (b) 20 min, αB-crystallin signals were positive mainly in the cytoplasm but weaker compared to the control group; (c) 40 min, αB-crystallin signals were still detected in the cytoplasm but stronger than at 20 min of heat stress; (d) 60 min, αB-crystallin was still localized in the cytoplasm; (e) 80 min, weaker positive αB-crystallin signals were still mainly expressed in the cytoplasm; (f) 100 min, αB-crystallin was expressed weakly in the cytoplasm.
Figure 4.
Localization of αB-crystallin in H9C2 cells before and after heat stress in vitro.
Immunocytochemical staining, scale bar = 10 µm. αB-crystallin (green color, FITC), nuclei (blue color, DAPI) (a) αB-crystallin was localized in the cytoplasm of non-stressed H9C2 cells. In heat-stressed H9C2 cells, the following were observed at the indicated time points: (b) 20 min, weaker positive αB-crystallin signals localized in the cytoplasm, compared with those of control group; (c) 40 min, αB-crystallin signals localized weakly in the cytoplasm; (d) 60 min, αB-crystallin signals were persistently weaker both in the cytoplasm and over the nucleus; (e) 80 min, αB-crystallin still localized over the nucleus and in the cytoplasm at a lower level; (f) 100 min, most strongly positive αB-crystallin signals localized in the cytoplasm as well as around and over the nucleus.
Figure 5.
αB-crystallin expression in rat hearts heat-treated in vivo.
αB-crystallin expression in rat heart tissue decreased (P<0.01) at 20 min of heat stress compared to the control and then significantly increased (P<0.01) at 40 min of heat stress. After 60 min of heat stress, αB-crystallin expression levels decreased again (P<0.01) and remained at lower levels until 100 min of heat stress. However, the level of αB-crystallin in dead rats was much higher than those of the control and all other heat-stressed groups. ** P<0.01; *P<0.05.
Figure 6.
αB-crystallin expression in H9C2 cells heat treated in vitro.
αB-crystallin decreased significantly (P<0.01) from 40 min to 60 min of heat stress compared to the control group. However, from 80 min to 100 min of heat stress, αB-crystallin levels increased and were not significantly different from that of the control group. ** P<0.01; *P<0.05.