B[a]P致SD幼鼠神经组织形态学损伤及其机制研究

Effects of benzo(a) pyrene exposure on morphology of the nervous system and its mechanism

目的 :通过观察苯并[a]芘(Benzo(a)pyrene,B[a]P)对新生SD大鼠脑组织形态学、超微病理学和生化指标的改变,探讨B[a]P神经发育毒性的分子机制。方法 :将48只新生雄性SD大鼠随机分为溶剂对照组、低剂量组、中剂量组、高剂量组,每组各12只,从出生后第5天始,每天灌胃1次,持续14 d。染毒后制切片,光镜、电镜观察海马形态学改变,化学比色法测定生化指标变化。结果:与溶剂组比较,染毒组幼鼠可见不同程度的脑组织损伤;海马组织超氧化物歧化酶含量、Na^+-K^+-ATP酶和Ca^(2+)-Mg^(2+)-ATP酶的活性明显下降,丙二醛含量明显增高,差异均具有统计学意义(P<0.05)。结论 :B[a]P可致新生SD大鼠神经发育毒性,其机制可能与海马组织氧化应激产生、Na^+-K^+-ATP酶和Ca^(2+)-Mg^(2+)-ATP酶活性下降有关。

Objective：To explore the relationship between Benzo（a）pyrene（B[a]P）exposure and the changes of morphology,oxidative stress and ATPase in hippocampus in newly born SD rats,and to examine the molecular mechanism of developmental neurotoxicity caused by B[a]P. Methods：Forty eight male new born SD rats were randomly assigned to one of the following four groups（n=12/group）：vehicle control group,0.02,0.2,2 mg/kg of B[a]P groups. The rats were given oral dose of B[a]P once a day for 14 days starting from the fifth day after birth. After infection period,optical slices and electron-microscope slices from brain（cortex,hippocampi,cerebellum and brain stem）were made to observe. The colorimetric technique was used to detect the activity of SOD,MDA,Na^＋-K^＋-ATPase and Ca^2＋-Mg^2＋-ATP in hippocampus. Results：Brain tissue damage at various degrees was observed in the B[a]P groups compared with that of control group. SOD content,Na^＋-K^＋-ATPase and Ca^2＋-Mg^2＋-ATPase of B[a]P groups decreased obviously compared with those of control group,and MDA content of B[a]P groups increased obviously,with statistically significant differences（P〈0.05）. Conclusion：B[a]P could lead to developmental neurotoxicity of new born SD rats,and the change of oxidative stress,the decreased ATPase may play an important role in B[a]P-caused developmental neurotoxicity.