This study investigated the gene expression profile in basal ganglia of manganese-exposed rats based on cDNA array analysis.

For cDNA array, 25 male Sprague-Dawley rats (250±25 g) were intraperitoneally injected with 25 mg/kg B.W./day of MnCl2 (0.3 ml) for 10 days. For dose-related gene expression analysis, rats were intraperitoneally injected with 0.2, 1.0, and 5.0 mg/kg B.W/day of MnCl2 for 10 days. Control rats were injected with an equal volume of saline. RNA samples were extracted from brain tissue and reversetranscribed in the presence of [alpha32P]-dATP. Membrane sets of the Atlas Rat 1.2 array II and Toxicology array 1.2 kit (Clontech, Palo Alto, CA) were hybridized with cDNA probe sets. Northern blot hybridization method was employed to assess the dose-related gene expression.

Fifty-two genes showed significant changes in expression of more than two-fold. Twentyeight were up-regulated and 24 were down-regulated in the manganese-exposed group compared to the control. Among the 52 genes, 28 genes including nuclear factor I-X1 (NF1-X1), neuroligin 2 and 3, mitochondrial stress-70 protein (MTHSP70), neurodegeneration-associated protein 1 (Neurodap1), multidrug resistance protein (MDR), and endoplasmic reticulum stress protein 72 (ERP72), were reported for the first time related to the manganese-induced neurotoxic-metabolism in the rat basal ganglia. According to the dose-related gene expression analyses, MTHSP70, Neurodap1 and ERP72 genes were up-regulated compared to the control even in the group exposed to low manganese dose (0.2 mg/kg B.W./day).

Twenty-eight genes detected for the first time in this study were closely related to the manganese-induced neurotoxic-metabolism in the rat basal ganglia and further study of these genes can give some more useful information about the manganese metabolism.