MK-801诱导的精神分裂症大鼠脑组织PV、GAD67和KCC2的表达变化

Changes in expression levels of PV, GAD67 and KCC2 in the brain tissue of rats with schizophrenia induced by MK-801

摘要:

目的：通过对地佐环平（MK-801）诱导的精神分裂症（SZ）大鼠脑组织小清蛋白(PV)、谷氨酸脱羧酶67(GAD67)以及K+-Cl-协同转运蛋白2(KCC2)表达的比较研究，探讨围产期NMDA受体阻断剂致SZ的γ-氨基丁酸(GABA) 机制。方法：36只新生雄性Sprague-Dawley 大鼠于出生后（postnatal, P）6 d随机分为2批，每批又随机分为正常对照组、SZ发育模型组和SZ慢性给药模型组。SZ发育模型组于P7~10 d皮下注射0.1 mg/kg MK-801，每日2次；SZ慢性给药模型组于P47~60 d腹腔注射0.2 mg/kg MK-801，每日1次；对照组和各模型组大鼠于相应时段注射0.9 %的生理盐水。P63 d，第1批大鼠断头取脑，多聚甲醛固定后行组织切片，以免疫组化方法检测内侧前额叶皮质（mPFC）和海马CA1区PV及GAD67的表达情况；第2批大鼠处死后取mPFC和海马组织匀浆，以免疫印记方法检测mPFC和海马组织KCC2的表达水平。结果：两模型组mPFC和海马CA1区PV以及GAD67的表达水平显著低于对照组（P<0.05）；SZ发育模型大鼠mPFC和海马CA1区的KCC2表达水平显著低于慢性给药模型组和对照组（P<0.05）。结论：MK-801诱导的SZ发育模型可模拟SZ患者大脑PV和GAD67的表达改变，并可能通过下调KCC2的表达影响mPFC和海马GABA递质系统的发育。

Abstract:

OBJECTIVE: To study changes in the expression levels of parvalbumin (PV), glutamate decarboxylase 67 (GAD67) and K+-Cl- cotransporter 2 (KCC2) in the brain tissue of rats with schizophrenia (SZ) induced by dizocilpine (MK-801), and to investigate the mechanism involving gamma-aminobutyric acid (GABA) by which NMDA receptor blocker induces SZ in the perinatal period. METHODS: Thirty-six neonatal male Sprague-Dawley rats were randomly assigned to two batches on postnatal day 6. Each batch was divided into normal control (treated by 0.9% normal saline), SZ-development model (treated by subcutaneous injection of 0.1 mg/kg MK-801 on postnatal days 7-10; bid), and SZ-chronic medication model groups (treated by intraperitoneal injection of 0.2 mg/kg MK-801 on postnatal days 47-60; qd). On postnatal day 63, the brain tissue of the first batch of rats was obtained and then fixed with paraform for histological sections; expression levels of PV and GAD67 in the medial prefrontal cortex (mPFC) and hippocampus CA1 were measured by immunohistochemistry. Simultaneously, the second batch of rats was sacrificed and the mPFC and hippocampus were obtained and homogenized; expression levels of KCC2 in the mPFC and hippocampus were measured by Western blot. RESULTS: Expression levels of PV and GAD67 in the mPFC and hippocampus CA1 were significantly lower in the SZ-development and chronic medication model groups than in the normal control group (P<0.05). Expression levels of KCC2 in the mPFC and hippocampus were significantly lower in the SZ-development model group than in the SZ-chronic medication model and normal control groups (P<0.05).ConclusionsThe expression changes of PV and GAD67 in SZ can be simulated using the SZ development model induced by MK-801, which might affect the development of the GABA system in the PFC and hippocampus by downregulating KCC2 expression.