母鼠妊娠期铅镉联合暴露对新生鼠大脑bcl-2,Bax和c-fos mRNA表达的影响及NAC保护效应

Influence of Combined Exposure to Lead and Cadmium on Bcl-2,Bax and c-fos mRNA Expression in Neonatal Brain and the Protective Effects of N-Acetylcysteine on Pregnant Rats

【目的】研究母鼠妊娠期铅镉联合暴露对新生鼠大脑bcl-2、Bax、c-fosmRNA表达的影响及N-乙酰半胱氨酸(N-Acetylcysteine,NAC)的保护作用。【方法】35只怀孕SD母鼠被随机分为7组,即A组为对照组(饮用蒸馏水)、B组为铅组(300mg·L-1)、C组为铅+NAC组(300mg·L-1+20mmol·L-1)、D组为镉组(10mg·L-1)、E组为镉+NAC组(10mg·L-1+20mmol·L-1)、F组为铅+镉组(300mg·L-1+10mg·L-1)、G组为铅+镉+NAC组(300mg+10mg·L-1+20mmol·L-1)。采用饮水染毒,染毒时间为21d,分娩后应用实时荧光定量PCR检测新生鼠大脑bcl-2、Bax、c-fosmRNA的相对表达。【结果】与对照组比较,各染毒组bcl-2mRNA表达降低,除B组外,D组、F组均差异显著(P<0.05),Bax、c-fosmRNA表达显著升高(P<0.05),其中以F组作用最为明显;NAC拮抗组与相应染毒组比较,除C组bcl-2mRNA表达与B组无显著性差异外(P﹥0.05),其余各组差异显著(P<0.05);Bax、c-fosmRNA表达均显著降低(P<0.05)。【结论】铅镉联合表现协同毒性效应,NAC对铅、镉致新生鼠大脑凋亡基因表达异常引起的脑细胞凋亡具有明显的保护作用。

[Objective] In order to observe the impact of low-level lead or/and cadmium and protective effect of N-Acetylcysteine in cortical neurons of neonatal SD rats, the cultured cortical neurons of neonatal rats were used to perform the toxicity test. [Method] Thirty-five adult female SD rats were divided into control group, lead acetate group （300 mg·L^-1）, lead acetate ＋ NAC group （300 mg·L^-1 ＋ 20 mmol·L^-1）, cadmium chloride group （10 mg·L^-1）, cadmium chloride ＋ NAC group （10 mg·L^-1＋20 mmol·L^-1）, group of lead and cadmium （300 mg·L^-1 ＋10 mg·L^-1）, group of lead and cadmium ＋ NAC （300 mg·L^-1 ＋10 mg·L^-1＋ 20 mmol·L^-1）, and the additives were given in the drinking water. After gestational periods the expressions of bcl-2, Bax and c-fos mRNA in brain of neonatal rats were detected by real time fluorescent quantitative PCR. [Result] In comparison with the control group, there was a significant decrease in the expression of bcl-2 mRNA except for B group （P〈0.05）, and the expression of Bax and c-los mRNA appeared a significant increase （P〈0.05）, especially F group. Compared NAC protective groups with the poisoning groups, the expression of bcl-2 mRNA increased to a certain extent （P〈0.05 or P〉0.05）, but the expression of Bax and c-fos mRNA significantly decreased （P〈0.05）. [Conclusion] The results showed that lead and cadmium appeared a synergetic effect, and it indicated that NAC could protect apoptosis of brain cells caused by exceptional gene expression from lead and/or cadmium in neonatal SD rats.