Statistical analysis
Data were presented as mean ± SEM and statistically significant were considered if p < 0.05. One-way ANOVA with Dunnett’s post-hoc test, Spearman’s rank correlation, Linear regression were performed for statistical comparisons via IBM SPSS Statistics 19.0 and GraphPad Prism 6 software (GraphPad Software, Inc., La Jolla, CA, USA).