الفهرس 
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Abstract
The present work was done to investigate the possible toxic effect of silver nanoparticleson the neuronal cells of cerebral cortexof male mice.To achieve such a purpose, mice were divided into three groups (each of 15) according to their approximately equal mean body weights. Experimental mice were injected intraperitoneally for 28 days with the synthesized citrate-coated AgNPs (dissolved in saline solution), and at a concentration of 100 and 1000 mg/kgbw. The study will include the following aspects characterization of silver nanopartices (AgNPs), including nanoparticle size, shape, distribution (polydispersity), and its absorption (UV-VIS spectral analysis).
Evaluation the general symptoms of toxicity, body and brain weights.
Detection of the presence of silver element in the brain tissues of both control and the treated mice, using EDX analysis.
Estimation of some biochemical parameters in the brain tissues, such as acetylcholine esterase enzyme activity, the total antioxidant capacity, and the dopamine neurotransmitter concentration.
Estimation of biophysical properties of the brain tissues, including conductivity and permittivity.
Histological examination of the neuronal cells of cerebral cortex of both control and experimental treated mice.
Ultrastructural investigation of the pyramidal neurons, their axons extensions as well as synaptic transmission.
The results of the present study revealed that:
The results of particle size analyzer for citrate coated AgNPs showed that more than 90% of the prepared particles are in average size of 26.9 nm, and about 10% of the particles are oversized with baseline error of 1.34%. Further, the polydispersity of most these particles is 0.74 (i.e. less than 1), indicating the homogeneous distribution of the particles.
Examination by the transmission electron microscope revealed that the majority of the citrate-coated AgNPs are spherical in shape, having smooth surfaces (homogeneous), and showed low level of agglomeration (adhesion) and have high level of uniformity.
UV-visible spectrum analysis showed that the maximum absorption wavelength for the particles is at 422 nm.
4.The results showed no observed changes in the general health of mice, where most animals keep their body sizes. Further, no dead mice were recorded in both control and 100 mg/kg bwAgNPs during the duration of experiment. However, only 3 (20%) of mice were died with 1000 mg/kg bwAgNPs. Moreover, the results revealed no significant differences in the relative brain weights as well as in the body weights of mice treated with the two different concentrations of AgNPs, compared with the control.
5.The energy dispersive X-ray analysis of the brain tissues of both control and the treated mice revealed considerable high levels and high spectral peaks of silver were recorded in the brain tissues of mice administered with the high dose (1000 mg/kg bw) AgNPs, compared with those treated with the low dose (100 mg/kg bw), indicating the accumulation. However, no observed silver was detected in the brain of the control mice.