[Morphological study on the neural tube defects caused by passive smoking]

To investigate the possible mechanisms of teratogenesis caused by passive smoking.

The stereomicroscope and electron microscope were used to observe the effects of passive smoking on the development of golden hamsters' neural tube and alternations of neuroepithelial ultrastructures.

Passive smoking could induce teratogenesis during neurulation (chi 2 = 51.28, P < 0.01). The main forms of neural tube defects were spina bifida, exencephaly, and so on. In embryos of every passive smoking group, neuroepithelial cells arranged irregularly. The intercellular spaces became wide. The apical portion of many neuroepithelial cells bulged out into the lumen and many microvilli were shorted and swollen. A lot of vacuolation appeared in the cytoplasm. The cristae of mitochondria reduced even disappeared, and some mitochondria became elongate. Irregular nuclear, increased heterochromatin and karyopycnosis/karyorrhexis were observed easily. Perinuclear cisternae partially swollen and embraced tangible material. Some death cell's decomposed a lot of apoptotic bodies. Most of the apoptotic bodies were found within the cytoplasm of otherwise healthy-looking or healthy cells.

These data prove that passive smoking can cause dymorphogenesis of the neural tube. And tobacco smoking might induce excess degeneration, death, and cells loss in the neural tube and mesenchyme, thereby resulting in failure of formation and differentiation of neural tube.