AGTR1 and periodontitis: Figure 3 shows that ligature-induced periodontitis increased the TLR2 relative RNA expression as significant differences were found between the ligature groups (WT-L, AT1-L and AT2-L) and their respective control groups, without ligature, WT-NL (p < 0.05), AT1-NL (p < 0.01) and AT2-NL (p < 0.01).