Statistical analyses
All statistical analyses were performed with JMP Pro, Version 14 (SAS Institute Inc., Cary, NC, 1989–2007). Mean values and standard deviations were calculated and Shapiro-Wilk-W-tests for testing of normality was conducted. As the data was non-normally distributed, a Kruskal-Wallis/Wilcoxon test, followed by pairwise comparison with Wilcoxon method, was carried out.