Table 4. The mean and standard deviation (SD) of the optical density of Nissl’s granules in the different experimental groups.

Group	Mean ± SD
Control	10.99 ± 0.7
Au-NP50	3.349 ± 0.2
Au-NP25	5.42 ± 0.6

Au-NP₅₀, gold nanoparticles 50 ppm for 5 days; Au-NP₂₅, 25 ppm Au-NPs for 10 days.