癫痫动物模型的建立及多药耐药基因产物P-糖蛋白的表达

The establishment of animal model of focal epilepsy and P-glycoprotein expression of mdrl

目的 建立局限性癫痫动物模型,探讨多药耐药基因产物P-糖蛋白的表达规律以及癫痫耐药机制。方法 42只Wistar大鼠随机分为对照组,海人酸致痫组,苯妥英钠(phenytoin sodium,PHT)+苯巴比妥(phenobarbital,PB)和加巴喷丁(gabapentin)抗癫痫药物干预组。致痫组大鼠于右侧海马区注射海人酸,于给药后第6h、24h、3d、5d和7d处死;干预组大鼠在注射海人酸前30min,分别行加巴喷丁(20mg/kg)或PHT(3～90mg/kg)+PB(30mg/kg)腹腔注射,然后注射海人酸,给药后第6h、3d、5d和7d处死。所有动物均采用免疫组织化学法检测多药耐药基因-1的表达产物P-糖蛋白。结果 对照组大鼠无癫痫发作。致痫组大鼠均出现癫痫发作,经抗癫痫药物干预的大鼠,癫痫发作的开始时间延迟、持续时间缩短(P<0.01)。不同剂量PHT组大鼠癫痫发作开始和持续时间有所不同,组间比较差异有显著性意义(P<0.01);随PHT剂量的增加,P-糖蛋白表达增高。干预组阳性细胞数高于致病组(P<0.01)。注射海人酸后6h,出现P-精蛋白强烈表达,3～5d后减弱,7d后完全消失;但干预组大鼠,在给药后第3d仍强烈表达,并逐渐增强,直至第7d仍无减弱趋势。结论 (1)一侧海马区注射海人酸,可成功地建立癫痫模型;(2)抗癫痫药物可使多药耐药基因-1的表达产物P-糖蛋白表达增强。

Objective To establisht the animal model of focal epilepsy, and study the patterns of P-glycoprotein (PGP) expression of multidrug resistant gene (mdr 1) and the drug resistant mechanism in epilepsy. Methods Forty-two healthy male Wistar rats were divided into control group (Group Ⅰ ), kainic acid (KA) epileptogenesis group (Group Ⅱ) and interference group (Group Ⅲ). In Group Ⅰ (n=3), 1 μl NS (instead of KA) was injected into the right hippocampus. In Group Ⅱ (n=15), 1 μl KA was injected into each rat's right hippocampus and sacrificed at 6 h, 24 h, 3d, 5 d and 7 d after injection. In Group Ⅲ (n=24) gabapentin (20 mg/kg) or phenytoin sodium (PHT, 30-90 mg/kg) + phenobarbital (PB, 30 mg/kg) were injected intraperi-toneally respectively, and 30 minutes later KA was injected into right hippocampus then sacrificed at 6 h, 3 d, 5 d and 7 d. PGP expression of mdrl was examined by immunohistochemistry in the left hippocampus of different groups of rats. Results All the rats had seizures after KA was injected (10±1.5) min. The epilepsy was not found in control group. In Group Ⅲ, the initial seizure time was delayed, duration was shorten compared with Group I (P<0.01). In different dosages of PHT, 60 mg/kg, 70 mg/kg compared with 30 mg/kg, the initial time and the duration time had significant difference (P<0.01). The PGP expressed rate would increase along as well as the raising of PHT dosage. The number of immunohistochemistry reactive positive cells in immunohistochemistry between Group Ⅲ and group Ⅱwere with significant difference (P<0.01). The PGP was strongly expressed in rats after injection of KA in 6 h, attenuated in 3-5 d and completely disappeared in 7 d. But in the Group Ⅲ, PGP was still strongly expressed in 3 d, until 7 days it was more intensely expressed without any reducing tendency. Conclusion 1) The animal model of focal epilepsy could be established successefully by injecting of KA into the hippocampus of Wistar rat. 2) The PGP expression of mdr 1 can be increased by anti-epilepsy drugs, and it is enhanced by increasing drug dosage.