Effects of Nonylphenol (NP) Exposure During Pregnancy on Nissl Body of Rat Cerebral Cortex

Objective To explore the effect of NP exposure during gestation on the Nissl body of cortex in filial rats.

Methods regnant rats were treated by gavage with NP at the dosage of 0, 50, 100 or 200 mg/kg each day on the 8^th to 14^th day after gestation. Filial rats were killed at the 21^st and 61^st day after birth; brain tissues were stained by HE and modified Nissl method.

Results By staining with HE method, the appearance of cortex neurons was shrinking in low NP treated group; and the arrangement of cortex neurons appeared disorder, scattered sparsely, and obvious depigmentation with the increase of NP dosage. The nuclei of neuron in treated groups were smaller and darker than the normal. By staining with Nissl method, the number of Nissl bodies in cortex neurons in treated groups was reduced with the increase of NP exposure in comparison with the control group. The distribution of Nissl bodies appeared uneven, different shapes and inconsistent in the depth of dyeing color and transparency. The optical density of the stained specimen was significantly different between the high NP treated group and the control group (P < 0.05).

Conclusions NP exposure during gestation could cause the morphological alteration of cortex neurons in filial rats, these alterations were obvious with the increase of NP exposure, which might be one of the reasons inducing the decrease of learning and memory ability in filial rats.