Regarding the effects of the 16-week probiotic treatment on dopaminergic cells in the SNpc, the results of TH immunohistochemistry are shown in Figure 4A. The TH-positive cells in the SNpc at the age of 24 weeks in PD mice are quantified in Figure 4B. PD mice receiving probiotic treatment showed preservation of TH-positive cells in the SNpc (t = 2.22, p = 0.045) compared to the sham treatment group. The gene discussed is TH; the disease is Parkinson disease.