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目的探讨急性染铅对大鼠海马Ca2+-Ca2+/钙调蛋白依赖蛋白激酶Ⅱ(CaMKⅡ)信号转导通路影响及作用机制。方法取30 d健康大鼠海马脑片分别用含醋酸铅(20μmol/L)及不含醋酸铅的人工脑脊液(ACSF)孵育,分对照组、谷氨酸组、CaMKⅡ抑制剂(KN-93)组、谷氨酸+醋酸铅组,培养30 min后收集脑片,用Western Blot方法检测谷氨酸组、KN-93组、铅组中环腺苷酸(cAMP)反应元件结合蛋白(CREB)的活性。结果染铅组于染铅0、120min时CREB活性分别为(0.305 6±0.020 8)和(0.172 2±0.023 3),随染铅时间延长明显降低;谷氨酸使磷酸化CREB活性提高47%,对非磷酸化CREB活性无影响;KN-93及谷氨酸+醋酸铅组CREB活性分别下降20%,45%,总量CREB表达无明显改变。结论急性铅中毒可能通过抑制CaMKⅡ活性影响下游信号分子,造成对学习记忆功能的损伤。
Objective To investigate the effect and mechanism of acute lead exposure on Ca2 + -Ca2 + / CaMKⅡ signal transduction pathway in hippocampus of rats. Methods The hippocampal slices of healthy rats were pretreated with lead acetate (20μmol / L) and lead acetate-free artificial cerebrospinal fluid (ACSF) for 30 days. The rats in control group, glutamate group, KNM- Glutamate + lead acetate group. After cultured for 30 min, brain slices were collected and the activity of cAMP response element binding protein (CREB) in glutamate group, KN-93 group and lead group was detected by Western Blot. Results CREB activity was 0.305 6 ± 0.020 8 and 0.172 2 ± 0.023 3, respectively, at 0,120 min in lead-exposed group, and decreased significantly with prolonged lead exposure. Glutamate increased the phosphorylated CREB activity by 47% , No effect on non-phosphorylated CREB activity; CREB activity in KN-93 and glutamate + lead acetate group decreased by 20% and 45%, respectively, and the total CREB expression did not change significantly. Conclusion Acute lead poisoning may affect the learning and memory impairment by inhibiting the activity of CaMKⅡin downstream signaling molecules.