对氨基水杨酸钠对染锰大鼠基底核GABA_AR及GAT-1表达的影响

Effect of PAS-Na on GABA_AR and GAT-1 Protein and mRNA Levels in Basal Ganglia of Manganese-Exposed Rats

[目的]探讨对氨基水杨酸钠(PAS-Na)对短期或亚慢性染锰大鼠基底核γ-氨基丁酸(gamma-aminobutryicacid,GABA)A受体(GABAAreceptor,GABAAR)及GABA转运载体-1(GABA transporter-1,GAT-1)表达的影响。[方法]将短期实验大鼠分为染锰组、PAS低(L-)、高(H-)剂量治疗组和对照组,观察期为7、10周;将亚慢性实验大鼠分为对照组、染锰组、PAS预防组和PAS低(L-)、中(M-)、高(H-)剂量治疗组,观察期为4、8、12、18周。用实时荧光定量聚合酶链反应(RT-PCR)、免疫印迹法(Western blot)检测大鼠脑基底核GABAAR及GAT-1表达。[结果]短期实验中,观察期7周,染锰组GABAAR蛋白表达较对照组高(P<0.05);观察期10周,染锰组GABAAR和GAT-1 mRNA表达较对照组低,L-PAS、H-PAS治疗组基底核GAT-1 mRNA表达较染锰组高(P<0.05)。亚慢性实验中,观察期4周,染锰组GABAAR mRNA表达较对照组高(P<0.05);观察期8周,染锰组GABAAR mRNA表达较对照组低,预防组GABAAR mRNA表达较染锰组高(P<0.05)。观察期12周,染锰组GABAAR蛋白表达较对照组高,预防组GABAAR蛋白表达较染锰组低(P<0.05)。观察期18周,染锰组GABAAR mRNA表达较对照组低,GAT-1 mRNA表达较对照组高,H-PAS治疗组GAT-1 mRNA表达较染锰组低(P<0.05)。[结论]短期或亚慢性锰暴露对大鼠基底核GABAAR和GAT-1 mRNA表达都有明显的毒性影响,PAS-Na对亚慢性锰暴露致GABAAR mRNA或蛋白表达改变有预防性干预作用,对锰致大鼠基底核GAT-1 mRNA表达改变有治疗性干预作用。

[ Objective ] To explore the effect of sodium para-aminosalicylate （PAS-Na） on the expression of gammaaminobutryic acid type A receptor （GABAAR） and gamma-aminobutryic acid transporter （GAT-1） in short-term or subchronic manganese （Mn）-exposed rats. [ Methods ] In the short-term experiment, rats were divided into control, Mn-exposed, lowdose PAS-Na （L-PAS） and high-dose PAS-Na （H-PAS） groups, each subgroup of 10 rats were necropsied at the end of week 7 and 10. In the subchronic experiment, rats were divided into control, Mn-exposed, PAS-Na prevention （P-PAS）, and L-PAS, M-PAS （middle-dose PAS-Na） and H-PAS groups, and were observed at week 4, 8, 12 and 18. The mRNA and protein expression of GABAAR and GAT-1 in rat basal ganglia were examined by real-time fluorescence polymerase chain reaction （RT-PCR） and Western blot （WB）. [ Results ] In the short-term experiment, on observation week 7, GABAAR protein expression was significantly increased in Mn-exposed group （P 〈 0.05）; on observation week 10, GABAAR and GAT-1 mRNA expression were significantly decreased in Mn-exposed rats （P 〈 0.05）, and L-PAS and H-PAS treatment restored their GAT-1 mRNA expression （P〈 0.05）. In the subchronic experiment, on obervation week 4, GABAAR mRNA expression was greatly increased in Mn-exposed rats （P 〈 0.05）; on observation week 8, GABAAR mRNA expression was greatly decreased in Mn-exposed rats vs controls （P 〈 0.05） and increased in P-PAS group vs Mn- exposed rats （P 〈 0.05）; however, on obervation week 12, GABAAR protein expression was greatly increased in Mn-exposed rats vs controls （P 〈 0.05） and decreased in P-PAS vs Mn-exposed rats （P 〈 0.05）; on observation week 18, GABAAR mRNA expression was greatly decreased in Mn-exposed rats vs controls （P〈0.05）, and GAT-1 mRNA expression was greatly increased in Mn-exposed rats vs controls （P〈0.05） and decreased in H-PAS vs Mn-exposed rats （P〈0.05）. [ Conclusion ] Short-term and subchronic exposure of manganese exhibited obvious toxic effects in the expression of mRNA GABAAR and GAT-1 in basal ganglions of rats. PAS-Na played a preventive intervention role in thee GABAAR mRNA or protein expression of subchronic Mn-exposed rats and a therapeuticintervention role in the GAT-1 mRNA expression.