highly significantp < 0.01
**** (p < 0.0001), *** (p < 0.001) both represent a highly significant level, ** represents a high significance level (p < 0.01) and * represents a significant level (p < 0.05) compared with the DEN control group.
**** (p < 0.0001), *** (p < 0.001) both represent a highly significant level, ** represents a high significance level (p < 0.01) and * represents a significant level (p < 0.05) compared with the DEN control group.