牛磺酸锌对铅暴露雄性大鼠血脑屏障通透性的影响

Effects of Taurine-zinc on Blood-brain Barrier Permeability of Rats Exposed to Lead

目的探讨牛磺酸锌(taurine-zinc,TZC)对生长发育期铅暴露雄性大鼠血铅含量和血脑屏障(blood-brain barrier,BBB)通透性的影响。方法选取3周龄雄性SD大鼠,随机分为对照组、乙酸铅组、二巯丁二酸(dimercaptosuccinic acid,DMSA)组和TZC组,每组8只。TZC组大鼠饮用0.46g/L的TZC,其余各组大鼠均饮用自来水。乙酸铅组、DMSA组和TZC组大鼠腹腔注射0.12%乙酸铅生理盐水溶液(每100g体重0.2ml),DMSA组大鼠灌胃5mg/ml的DMSA(每100g体重0.2ml)。染毒3周后,以原子吸收法测血铅含量,以硝酸镧示踪法观察血脑屏障通透性变化。结果与乙酸铅组相比,TZC组和DMSA组血铅含量显著降低(P<0.01);透射电镜观察显示,对照组未见镧盐颗粒渗透出血脑屏障,乙酸铅组大鼠普遍出现镧盐颗粒穿过血脑屏障进入神经网络,TZC组和DMSA组均有部分毛细血管存在镧盐颗粒透过内皮细胞到达基膜,但未穿过基膜进入神经网络。结论TZC能显著降低铅暴露大鼠血铅含量,对血脑屏障有良好的保护作用。

Objective To explore the effects of taurine-zinc （TZC） on blood lead content and blood-brain barrier （BBB） permeability of growing rats exposed to lead. Methods Male SD rats aged 3 weeks were randomly divided into four groups （8 in each group）： control group, lead exposure group, dimercaptosuccinic acid （DMSA） group and TZC group. The exposure group treated with 0.12% lead acetate （0.2 ml/100 g body weight） by intraperitoneal injection, DMSA group and TZC group were treated with the same dose of lead acetate but were respectively supplemented with 5 mg/ml DMSA（2 ml/100 g body weight） by ig and 0.46 g/L TZC solution through drinking. Three weeks later, blood lead content was measured by atomic absorption spectroscopy （AAS） and changes of BBB permeability were observed using lanthanum nitrate tracer method. Results Compared with the lead exposure group, the blood lead level in TZC group and DMSA group was significantly reduced （P〈0.01）. Under transmission electron microscope, it was found that the lanthanum granules generally seeped into neural network through BBB in lead exposure group, but those only to basement membrane through some capillary endothelial cell in TZC group and DMSA group. Conclusion TZC can significantly reduce the blood lead level and protect BBB from injury induced by lead exposure.