The effects of sodium arsenite on mRNA expression of thioredoxin system in the liver of rat

Objective To observe the effects of sodium arsenite (NaAsO2) on mRNA expression of thioredoxin (TRX) system in the liver of rat. Methods Totally 36 Wistar rats were divided into three groups including control group (drink distilled water, n= 12), and NaAsO2 groups (10, 50 mg/L, n= 12) by random number table methord, which were sacrificed after 3 and 6 months. The mRNA expression of TRX system [including thioredoxin 1 (TRX1), thioredoxin 2 (TRX2), thioredoxin reductase 1 (TR1), and thioredoxin reductase 2 (TR2)] in the liver of rat was detected by quantitative real-time PCR. Results Rats were sacrificed after 3 months, compared among the three groups, the difference of TRX1 mRNA expression was statistically significant (F= 5.434, P 0.05), besides, TRX1 mRNA expression in high-dose group (1.766 ± 0.374) was higher than that of control group and low group (0.926 ± 0.329, 1.212 ± 0.546, all P 0.05), among them, TRX1 mRNA expression in low and high-dose groups (0.717 ± 0.139, 0.622 ± 0.261) were lower than that of control group (1.059 ± 0.356, all P < 0.05). Compare with the 3rd month, TRX1, TRX2 and TR1 mRNA expression in high-dose group of the 6th month were significantly decreased (1.766 ± 0.374 vs 0.622 ± 0.261, 1.692 ± 0.619 vs 0.880 ± 0.277, 1.601 ± 0.248 vs 0.633 ± 0.284, t= 6.144, 2.930, 3.532, all P < 0.05). Conclusions mRNA expression of TRX system is obviously affected by NaAsO2. Our results have showed that with the increase of arsenic's dose and time, the mRNA expression of TRX 1 has increased at the 3rd month, however, which is decreased at the 6th month. TRX may play an important role in the mechanism of liver injury induced by arsenic poisoning via oxidative stress. Key words: Arsenites; Rats; Liver; Thioredoxin