Statistical analysis
All continuous variables were expressed as the median with an
interquartile range(IQR) or mean with standard deviation(SD), as
appropriate. All groups were tested for the normal distribution with a
Kolmogorov-Smirnov test. For the normally distributed data, a one-way
analysis of variance (ANOVA) was used to analyze more than two groups.
Data that were not normally distributed were tested by a one-way
Kruskal-Wallis test for more than two groups. All statistical analysis
was carried out using Graphpad Prism version 5 (GraphPad, La Jolla, CA,
USA) and SPSS 22.0 (College Station, TX, USA) software. In the graphs,
the p values are indicated as follows: * < 0.05; **
< 0.01; *** < 0.001.