日本血吸虫尾蚴穿透皮肤机理的探讨及其预防药物的筛选

A STUDY ON MECHANISM OF SKIN PENETRATION BY CERCARIA OF S.JAPONICUM AND SCREENING OF PREVENTIVE DRUGS

作者用放射免疫法,测定感染日本血吸虫尾蚴的小鼠皮肤中前列腺素E_1(PGE_1)的含量。结果感染组的PGE_1显著高于正常对照组(P<0.01),且随感染尾蚴的数量增加而增加。使用7种PG抑制剂,其中阿斯匹林、布洛芬及消炎痛有一定预防尾蚴穿透作用,4种受体阻断剂无明显预防作用。抗血吸虫药吡喹酮400mg/kg,感染前2h减虫率最佳,用药至感染时间愈长,其预防作用愈弱。作者对以上结果进行了讨论,认为日本血吸虫尾蚴穿透皮肤的过程中,有PGE_1参与。前列腺素抑制剂具有一定的预防尾蚴穿透皮肤的作用。

Mice pretreated with PG cyclo-oxygen-ase inhibitor aspirin, at 300 mg/kg/d×5,and ibuprofen, at 100 mg/kg/d×5 orallyand 20 mg/kg/d×3 intraperitoneally reveal-ed moderate chemoprophylactic effects andthe reduction of the penetration of worms by23％ when compared to controls. Daily oraladministration of aspirin, at 300 mg/kg for15 days the worms reduction increased to41.7％.In estimation of PGE_1 in cercariae ofS.japonicum by radioimmunoassay, the PGE_1was 49 pg/100 cercariae. In normal mouseskin PGE_1 has been measured to amount to3105±691.7 pg/10 mg on average. In cercarial penetrated mouse skin, 1.5hours after exposure the PGE_1 assesed in 100and 250 cercariae in the infected skin were5506±1127.1 and 12085±2622.9 pg/10 mgrespectively, which were significantlyhigher than that of the non-penetrated skin.These studies in conjunction with our pre-vious work indicate that: 1.PGs, similar toS. mansoni, were probably necessary forcercarial penetration. 2.PG inhibitors couldreduce cercarial penetration. Receptors antagonist etc. e.g. diphen-hydramine, chlorpheniramine, atropine,practolol could not reduce cerearial penetra-tion, but praziquantal in the pretreatedmice could reduce cercarial penetration sig-nificantly, e. g. 400 mg/kg orally 2 hoursprior to affection of cercariae about 100％reduction of the penetration, but if pre-treated with praziquantal, 4, 8, 24, 36hours prior to the affection the reductionpenetration decreased to 51.7, 46.1, 9.4,8.9％ respectively.