Comparison of Zinc level during the mophometric development of rat hippocampus: from embryonic to postnatal second week

Hippocampus area contains a high concentration of zinc which plays a role in synaptic transmission and probably plasticity andippocampus development. This study aimed to assess zinc level in the hippocampal formation of rat embryos by using Timm method and its relation with volume changes of subregions of hippocampus before and after birth. In this study، wistar rats'' embryos on days 11، 21 and postnatal days of 7 and 14 were used. Samples were stained by Timm method and the degree of staining was quantified by Mat lab7. 5 software، The volume of hippcampal sub regions were estimated by cavalieri’s method. The results were analyzed in Mat lab software7. 5. Timm staining on embryonic days of 21 and 11 before birth and first and second weeks after the birth were negative. The quantified results of Timm staining showed no significant level of difference (p>0. 05). The volume difference of dentate gyrus،CA3 and CA1 regions showed no meaningful difference till seventh day postnally (p>0. 05). while the volume changes of the day 14 after birth showed significant level of difference in comparison with the postnatal day of 7 and embryonic days of 11 and 21 (p<0. 05). It seems zinc dose not play a role during morphometric development of hippocampus and hippocampus attains its final shape from postnatal Second week.