الفهرس 
NicotineOnly 14 pages are availabe for public view
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Abstract
This study was carried out to detect the effect induced by prenatal nicotine injection on postnatal development of sensory cerebral cortex of the albino rats. A total number of 30 pregnant albino rats were used.
The pregnant rats were divided into two groups as follows:
Group I: Group I: 15 rats were injected subcutaneously with normal saline twice daily throughout pregnancy (8 am and 5 pm). Their offspring (Eighty four offspring) constituted the control group I (C).
Group II: 15 rats were injected subcutaneously with nicotine sulfate (2.5 mg/Kg/day) in two divided doses throughout pregnancy (8 am and 5 pm). The mother gave birth prematurely. Four mothers delivered on days 18 while nine mothers delivered on day 19 and two delivered on day 20 of gestational period. Their offspring (Eighty two) constituted the treated group II (T).
Some of the viable offspring of the two groups were anaesthetized with ether on postnatal day (PND) 1, 10, 20 and 40. Gross morphological examination was performed for detection of any apparent congenital anomalies. The brain was fixed in Bouin’s solution for ten days, then weighed, paraffin blocks were prepared and parasagittal sections were performed and stained using haematoxylin and eosin, and toluidine blue modification stain. Other sections were impregnated in silver. Other viable offspring of the two groups were perfused with fresh Karnovsk’s fixative. Coronal sections of cerebral sensory cortex were performed. Semithin and ultrathin sections were cut and examined under the light and electron microscope.
The thickness of ten cerebral sensory cortex was measured in each age of the treated groups and compared to control groups. The diameters of 40 pyramidal cells in lamina V were measured in different fields in the cerebral sensory cortex. The number of pyramidal cells in ten fields of lamina V of the cerebral sensory cortex was counted. All results were tabulated and statistically analyzed.
Results:
There was an insignificant reduction in nicotine exposed offspring body weight at all ages studied compared to the control group. There was significant reduction in brain weight of treated group compared to control group at PND1 only. A significant decrease in the thickness of sensory cortex occurred at all ages studied.
At PND1, abnormally placed neurons were observed in lamina I. The cells appeared to be arranged in groups rather than columnar pattern. Decreased nerve fiber density was noted. Depleted and fragmented apical dendrite of pyramidal cell were observed.
At PND10, partial depletion of apical dendrite of pyramidal cells were observed in lamina V. few pyramidal cells showed loss of nuclear details. Also, decreased nerve fiber density was noted.
At PND 20, abnormally placed neurons with vesicular nucleus were observed in lamina I. Decreased nerve fiber density was noted. Partial depletion of apical dendrite of pyramidal cell was noted in lamina V with appearance of large amount of neuroglial cells in between.
At PND 40, astrocytes with abundant eosinophilic cytoplasm were seen in lamina IV. Partial depletion of apical dendrite of pyramidal cells and others with karyorrhexis were observed in lamina V. Macrophages with vacuolated neuropil appeared at LVI.
By electron microscope, pyramidal cells of treated rat at PND1 showed clumping of nuclear chromatin. Their cytoplasm contained multiple vacuoles, detailess mitochondria and large amount of lysosomes. whereas in PND 10, 20 and 40 the pyramidal cells showed cytoplasmic vacuoles, minimal amount of free ribosomes and detailless mitochondria.
All results were discussed.