Statistical analysis
Data are presented as mean ± SD. SPSS16.0 software was used for all
statistical analysis. Statistical significance was determined by
independent biological samples student’s t-test for comparison of two
groups and one way ANOVA for comparison of three or more groups.
Differences were considered statistically significant when P <
0.05. P-values are indicated by “*” when P < 0.05 or “**”
when P < 0.01.