Statistical analysis
Results obtained for each SLIL region subjected to each analytical
technique were statistically compared with each control tissue. The two
regions that we analyzed from each of the zones originally established
by Berger were also compared (D1 vs. D2, M1 vs. M2 and P1 vs. P2).
First, we evaluated the normality of each distribution using the
Shapiro-Wilk test. As none of the distributions fulfilled the criteria
of normality, comparison between two specific groups of samples were
carried out using the non-parametric test of Mann-Whitney. The
comparisons were done with Real Statistics Resource Pack software
(Release 7.2) (Dr. Charles Zaiontz, Purdue University, West Lafayette,
IN, USA), available atwww.real-statistics.com. A
Bonferroni-adjusted statistical significance p value below 0.001
was set for all double-tailed tests, since multiple comparisons were
carried out at the same time.