Objective:To investigate the expression of SMI-32 in neocortex of Cortical dysplasia(CD)model Rats. Methods:Pregnant rats were injected carmustine (1

3-bis-chloroethy1–nitrosourea

BCNU) intraperitoneally on embryonic 17thday (E17)

cortical histology and immunohistochemistry were examined on the tissue of cerebral cortex of the offsprings at postonatal 28thday(P28). Results:Niss staining showed features of CD in the offsprings

including laminar disorganization

cytomegalic neurons and heterotopic neurons. Immunohistochemistry demonstrated that SMI-32 was expressed poorly in layerⅡ、Ⅴand the majority of them were expressed in layers Ⅳ

Ⅵ of the primary somatosensory and motor cortices with many abnormal neurons

part of them were in clusters

few were expressed in layer Ⅲ. Conclusion:SMI-32 was expressed abnormally in neocortex of CD model rats as one of layer-specific markers of cerebral cortex

and it may be an index of pathologic diagnosis of CD.