2.6. Statistical analysis
One-way analysis of variance (ANOVA) was used to analyse the data. Multiple comparisons were performed with Tukey's test to analyse differences between treatments. All statistical analyses were performed using the OriginPro software (version 8; OriginLab Corporation, Northampton, USA). The level of significance was set at P < 0.05, and the results are expressed as mean ± SEM.