Notably, the loss of dopaminergic neurons in the substantia nigra in response to MPTP was significantly ameliorated by VSL#3 and hMSCs alone as well as the combined use of them, and the survival of TH-positive neurons increased to 53.6%, 55.6%, and 61.0% that of control mice, respectively (Fig. 2, P < 0.01 versus PD), demonstrating the beneficial effects on dopaminergic neurons. The gene discussed is TH; the disease is Parkinson disease.