Expression and significance of Heat shock proteins 70 and Heat shock proteins 90 mRNA of residents exposed to arsenic via drinking water

Objective Through measuring and analyzing blood Heat shock proteins (HSP) 70 and HSP90 mRNA expression of different levels of arsenic exposure population, to explore the relationship between HSP70 and HSP90 mRNA expression and endemic arsenic poisoning. Methods The study subjects included a total of 226 residents exposed to arsenic via drinking water from two townships in the city of Bayannur (Shengfeng Township and Hangjinhouqishahai Township Wuyuan County) in Inner Mongolia Autonomous Region in 2011. The residents were divided into four groups according to drinking water arsenic concentration: control group (drinking water arsenic concentration < 10 μg/L), low exposure group (drinking water arsenic concentration 10-< 100 μg/L), middle exposure group (drinking water arsenic concentration 100-< 200 μg/L), and high exposure group (drinking water arsenic concentration ≥200 μg/L). Epidemiological investigation was carried out. Real-time PCR technology was used to detect the expression levels of blood HSP70 and HSP90 mRNA. And the relationships between the expression of HSP70 and HSP90 mRNA and water arsenic and urinary arsenic levels were analyzed. Results ①With the increase of arsenic concentration, the expression level of HSP70 mRNA increased first and then decreased. The HSP70 mRNA in the blood of high exposure group [2.44 × 10-3 (1.72 × 10-3)] and middle exposure group [3.01 × 10-3 (1.95 × 10-3)] were significantly different from that in the control group [2.27 × 10-3 (1.09 × 10-3), P < 0.05]. There was significant difference between the middle exposure group [3.01 × 10-3 (1.95 × 10-3)] and the low and high exposure groups [2.38 × 10-3 (1.55 × 10-3), 2.44 × 10-3 (1.72 × 10-3), P < 0.05]. The expression of HSP70 mRNA in blood of male [2.71 × 10-3 (1.90 × 10-3)] was slightly higher than that of female [2.34 × 10-3 (1.35 × 10-3), t= 2.523, P < 0.05]. ②With the increase of arsenic concentration, the expression level of HSP90 mRNA increased first and then decreased. The expression of HSP90 mRNA in the middle exposure group [1.29 × 10-2(1.04 × 10-2)] was significantly different from that in the control group [1.04 × 10-2 (0.83 × 10-2), P < 0.05]. The differences of HSP90 mRNA between the high exposure group [1.19 × 10-2 (0.88 × 10-2)] and the low and middle exposure groups [1.23 × 10-2(0.68 × 10-2), 1.29 × 10-2 (1.04 × 10-2)] were statistically significant (P < 0.05). ③The relative expression of HSP70 mRNA showed a U-shaped regression relationship with the level of urinary arsenic exposure (R2= 0.031, P < 0.05), and the expression of HSP90 mRNA was also correlated with urinary arsenic and nail arsenic (R2= 0.049, 0.036, P < 0.05). Conclusion Chronic arsenic exposure affects blood HSP70 and HSP90 mRNA expression. Key words: Arseniasis; HSP70 mRNA; HSP90 mRNA