2.856GHz和9.375GHz微波复合暴露致大鼠记忆功能障碍及海马组织结构损伤的定量化研究

Quantitative study on memory impairment and hippocampal damages induced by exposure of combined 2.856 GHz and 9.375 GHz microwaves in rats

目的 研究2.856 GHz和9.375 GHz微波复合暴露对大鼠记忆功能影响的规律及其组织结构基础。方法 将32只雄性Wistar大鼠随机分为假辐射组(Sham组)、2.856 GHz微波单一辐射组(S组)、9.375 GHz微波单一辐射组(X组)以及2.856 GHz和9.375 GHz微波复合暴露组(SX组)。采用新物体识别(novel object recognition,NOR)行为学实验对大鼠的记忆功能进行检测;采用苏木素-伊红染色(hematoxylin-eosin staining,HE)和尼氏染色(Nissl staining)技术分别对微波辐射后大鼠海马神经元显微结构和海马尼氏体含量进行定量分析;采用透射电子显微镜(transmission electron microscopy,TEM)观察大鼠海马组织超微结构变化情况。结果 (1)与Sham组相比,S组和SX组大鼠新物体偏好指数(preference index,PI)显著下降(S组:P<0.05,SX组:P<0.05)。相较于X组,SX组大鼠PI值也显著下降(P<0.05);(2) Sham组大鼠海马神经元显微结构未见异常,细胞核大表现为大、圆且淡染,S组、X组以及SX组大鼠海马神经元均表现出核固缩深染现象。定量化分析结果显示,与Sham组相比,S组和SX组大鼠海马神经元核固缩深染数量显著增多(S组:P<0.05,SX组:P<0.001)。相较于S组和X组,SX组大鼠海马神经元核固缩深染数量也显著增多(与S组比:P<0.05,与X组比:P<0.01);(3) Sham组大鼠海马神经元尼氏体含量丰富,S组、X组以及SX组大鼠海马神经元尼氏体含量均降低。定量化分析结果显示,与Sham组相比,S组、X组以及SX组大鼠海马神经元尼氏体平均光密度(mean optical density,MOD)均显著降低(S组:P<0.01,X组:P<0.01,SX组:P<0.01);(4) Sham组大鼠海马超微结构无显著异常,S组、X组以及SX组大鼠海马均表现出线粒体嵴断裂、肿胀空化、突触间隙模糊以及血管周间隙增宽等现象。相较于S组和X组,SX组大鼠上述超微结构损伤现象更为明显。结论 2.856 GHz和9.375 GHz微波复合暴露可导致大鼠记忆功能障碍和海马组织结构损伤,且复合暴露所致损伤效应重于单一频段微波辐射。

Objective To study the effects of combined 2.856 GHz and 9.375 GHz microwave exposure on memory ability and hippocampal structure changes in rats.Methods 32 male Wistar rats were randomly divided into a Sham group,a 2.856 GHz microwave radiation group(S group),a 9.375 GHz microwave radiation group(X group)and a combined 2.856 GHz and 9.375 GHz microwave radiation group(SX group).The memory ability of the rats after microwave irradiation were examined by the novel object recognition(NOR)test.The microstructure of hippocampal neurons and the content of neuronal Nissl body after microwave irradiation were evaluated by the hematoxylin-eosin staining and the Nissl staining.The changes of rat hippocampal ultrastructure were assessed by transmission electron microscopy(TEM).Results①compared with the Sham group,the preference index(PI)of rats in the S group and SX group significantly decreased(P<0.05 for the S group,P<0.05 for the SX group).Moreover,compared with the X group,the PI value of rats in the SX group also significantly decreased(P<0.05);②the microstructure of hippocampal neurons was normal,and the hippocampal neuronal nuclei were large and round in rats in the Sham group.However,the pyknotic nuclei were observed in the rats in both the S and SX groups.Quantitative analysis demonstrated that,compared with the Sham group,the number of pyknotic nucleus significantly increased in the rats in the S and SX groups(P<0.05 for the S group,P<0.001 for the SX group).Moreover,compared with the S and X groups,the number of pyknotic nucleus was significantly increased in the rats in the SX group(P<O.05 compared with the S group,P<O.Ol compared with the X group);③the hippocampal neurons in the Sham group had rich content of Nissl body.However,the Nissl bodies were significantly decreased in the rats in all the S,X,and SX groups.Quantitative analysis showed that,compared with the Sham group,the mean optical densities(MOD)of the Nissl bodies in hippocampus in the rats in the S,X,and SX groups were significantly reduced(P<0.01);①no damage on the ultrastructure of the hippocampus was observed in the rats of the Sham group.However,mitochondrial ridge fracture,swelling and cavitation,blurring of synaptic space,and widening of perivascular space were found in the hippocampus of rats in the S,X and SX groups.Moreover,compared with the S and X groups,the ultrastructural damages in the rats of the SX group were more obvious.Conclusion(Combined exposure of 2.856 GHz and 9.375 CHz microwaves can induce memory dysfunction and hippocampal damages in rats.Moreover,the damage caused by composite radiation is heavier than that caused by single-band microwave radiation.