Chronic exposure to arsenic in drinking-water damage to cognitive function, and nerve cells apoptosis is one of primary characteristic. The damage of mitochondrial structure and/or function is one of the main characteristics of apoptosis. Peroxisome proliferator activated receptor γ Coactivator α (PGC-1α) is involved in the regulation of mitochondrial biogenesis, energy metabolism and apoptosis. In this study, we aimed to study role of PGC-1α in sodium arsenite (NaAsO2)-induced mitochondrial apoptosis in rat hippocampal cells. We discovered that arsenic-induced apoptosis increased in rat hippocampus increased with NaAsO2 (0, 2, 10, and 50 mg/L, orally via drinking water for 12 weeks) exposure by TUNEL assay, and the structure of mitochondria was incomplete, swollen, lysosomes and lipofuscin increasing, and nuclear membrane shrunk observed by transmission electron microscope. Furthermore, NaAsO2 reduced levels of Bcl-2 and PGC-1α, increased the levels of Bax and Cytochrome C expression. Moreover, correlation analysis showed that brain arsenic content was negatively correlated with PGC-1α level and brain ATP content, respectively; PGC-1α level was negatively correlated with apoptosis rate; Brain ATP content was positively correlated with PGC-1α level; but no significant correlation between ATP content and apoptosis has been observed in this study. Taken together, the results of present study indicate that NaAsO2-induced mitochondrial pathway apoptosis is related to the reduction of PGC-1α, accompanied by ATP depletion.

Limited studies have shown that exposure to arsenic is associated with serum vitamin D levels, but the results are still inconsistent. A cross-sectional study of 762 participants was conducted in Wenshui Country, Shanxi Province, which was identified as an area of water-borne arsenicosis. The results showed positive relationship between arsenic species (iAs, MMA, DMA) and serum 25(OH)D. Binary logistic regression analysis showed that the significant increases of 0.4% and 0.6% in the risk of vitamin D excess for every 1-unit increment in the Box-Cox transformed urinary tAs and DMA, respectively. After stratifying populations based on arsenic methylation metabolic capacity, each one-unit increase in the Box-Cox transformed tAs level was associated with increases of 0.064 (95%CI: 0.032 to 0.096) in serum 25(OH)D in the populations with iAs% above the median. In the populations with skin hyperkeratosis, urinary iAs was positively associated with serum 25(OH)D (β=0.592, 95%CI: 0.041 to 1.143). Overall, our findings support the positive relationship between urinary arsenic and serum 25(OH)D.