镉诱导大鼠腺垂体细胞凋亡及与p38 MAPK&ERK1/2途径介导机制关系的初步研究

目的了解CdCl2对腺垂体的损伤以及细胞凋亡发生与p38MAPK、ERK12表达的关系,为了解镉致腺垂体毒作用的分子机制提供科学依据。方法采用健康雄性SD大鼠进行整体试验(n=12),分别每天经口灌胃给予0、1.0、2.0、4.0mgkgbwCdCl2,6周后取腺垂体进行指标检测;离体试验采用酶解分离大鼠之原代腺垂体细胞,分别以0、1.56、3.12、6.25、12.50、25.00、50.00、100.00μmolLCdCl2处理,收获细胞进行检测;特异性阻断剂阻断凋亡效应的试验采用2.65μmolLp38MAPK的特异阻断剂SB203580或10μmolLERK12激酶的特异阻断剂U0126处理细胞,然后以3.12μmolL或100.00μmolL的CdCl2处理细胞后进行相应的检测。检测指标包括:TUNEL法和流式细胞术等检测凋亡。结果整体实验和离体实验结果均显示CdCl2以剂量依赖方式诱导腺垂体细胞发生凋亡(P<0.05);特异性阻断剂效应的研究结果显示2.65μmolLSB203580和10μmolLU0126对TUNEL阳性细胞的相对灰度和凋亡细胞率均有一定的影响。结论在一定的剂量条件下,CdCl2影响腺垂体激素分泌水平,并导致发腺垂体细胞凋亡,MAPKs家族成员p38MAPK和ERK12激酶通路在凋亡发生过程中可能发挥一定的作用。

Effect on apoptosis of anterior pituitary induced by cadmium chloride and its relations with p38 MAPK＆ERK1/2 passway

OBJECTIVE: To study the effects of cadmium chloride on anterior pituitary and the relation between p38 MAPK&ERK1/2 passway and apoptosis induced by cadmium chloride. METHODS: In vivo studies, SD male rats were administered with CdCl2 at the doses of 0, 1.0, 2.0, 4.0 mg/kg bw by gavage for 6 weeks. In vitro studies, rats' anterior pituitary cells were primarily cultured and then treated with CdCl2 at doses of 0, 1.56, 3.12, 6.25, 12.50, 25.00, 50.00, 100.00 micromol/L for 6 hours. Inhabiting study, cells were incubated with SB203580 (2.65 micromol/L) or U0126 (10 micromol/L) respectively for 2 hours and then treated with CdCl2 at doses of 3.12, 100.00 micromol/L for 6 hours. The indices in above experiments included expression of TUNEL-positive cells, rate of apoptosis by Flowcytometry. RESULTS: The results showed that the apoptosis induced by CdCl2 inclined to enhance with dose dependent manner, Further more, U0126 and SB203580, the specific inhibitor of ERK1/2 and p38 MAPK respectively, could decrease the expression of TUNEL-positive cells significantly and lower apoptotic rate of primary cultured anterior pituitary cells. CONCLUSION: It was suggested that cadmium induce apoptosis of anterior pituitary both in vivo and in vitro in dose-dependent manner, ERK1/2 and p38 MAPK passways might play a role during above processes.