Moreover, aged mice presented fewer PDGFRα+ cells (day-3: 4.05 ± 0.48, day-10: 4.32 ± 0.87) compared to young mice (day-3: 4.67 ± 0.81, day-10: 7.86 ± 1.62) after ligation (Figure 4).These results suggest that the decreased number of PDGFRα+ MSCs could be one of the factors determining the increase in the number of inflammatory T and B cells, and the consequent increase in osteoclast-directed bone resorption in the ligature-induced periodontitis in aged mice. The gene discussed is PDGFRA; the disease is periodontitis.