Differences in Kynu expression between the groups in the substantia nigra and striatum. (A) Kynu expression in rotenone-treated rats without supplementation (R_WS—median: 0.006, min: 0.002, max: 0.062, n = 6) is practically nonexistent when compared to the sham group (** p < 0.05, fold change = −2.45). Those rotenone-treated rats that received the supplementation with folic acid and vitamin B12 (R_Sup—median = 1.97, min: 0.202, max: 9.05, n = 7) maintained the expression levels observed for the sham group (S—median = 1.74, min: 0.014, max: 10.49, n = 7), meaning that the rotenone-induced decrease in Kynu’s gene expression was prevented in the supplemented group (R_Sup) (* p < 0.05, fold change = −2.50). (B) There were no significant changes in Kynu expression between groups in the striatum. R_Sup—median = 4.05, min: 0.06, max: 32.06, n = 7; R_WS—median = 0.69, min: 0.03, max: 21.33, n = 7; S—median = 1.19, min: 0.02, max: 10.52, n = 7. Data are expressed as median (IQR). Min = minimum; max = maximum.