头部屏蔽对大鼠超致死剂量γ线照射后失能的防护作用

PROTECTIVE EFFECTS OF HEAD SHIELDING ON INCAPACITATION AFTER SUPRALETHAL γ-IRRADIATION IN RATS

大鼠头部用铅罩屏蔽,屏蔽部位中线组织剂量为未屏蔽组的40%.实验分两部分:(1)用转棒法观察头部屏蔽对照射后一般作业能力失能的影响.大鼠62只,分别照射300和400Gy.头部屏蔽组照射后比相应的全身照射组早期暂时性失能时间明显缩短,永久性失能期开始时间明显推迟;400Gy照射后狂暴性活动的发生率明显降低.(2)用迷宫法观察头部屏蔽对照射后高级神经活动(记忆能力)失能的影响.大鼠26只,分别照射200和100Gy.头部屏蔽组照射后躲避反应率和反应正确率的降低、反应时的延长和错误反应的程度均比相应的全身照射组明显减轻,因而使早期暂时性失能的严重程度明显减轻,永久性完全失能的开始时间明显推迟.本实验研究结果表明头部屏蔽减少60%的中线组织剂量对超致死剂量照射后的一般作业能力和高级神经活动的失能都有明显的防护作用.

The heads of rats were protected by lead shields.The midline tissue dose behind the shield was approximately 40 percent of the midline tissue dose at the same point without the shield in place.The experiments were done in two parts: (1)The protective effect of head shielding on the incapacitation of general performance capacity postexposure observed by rotarod method.Head shielding shortened significantly the early temporary incapacitation and postponed strikingly the onset time of permanent incapacitation after 300Gy and 400Gy irradiation;and decreased the incidence of frantic acitivity markedly after 400Gy irradiation. (2)The protective effect of head shielding on the incapacitation of higher nervous system activity postexposure observed by maze method.Head shielding alleviated significantly the decrease of avoidence and correct reaction,the prolongation of the reaction time and the degree of error after 200Gy and 100Gy irradiation.