Neurotransmitter and Amino Acid Analysis and Ultrastructural Observations of Fetal Brain Cortex Transplantation to Adult Rat Brain under the Effect of Dexamethasone

Abstract

To conduct an investigation of fetal cortical tissue graft survival using transmission electron microscopy and analyzing neurotransmitters and amino acids and their function, with special reference to the effect of dexamethasone. Transplantation of fetal cortical brain tissue to 100 adult Wistar albino rats weighing 170 to 220 g was performed. The rats were divided into three groups. Only transplantation of fetal cortical brain tissue was performed in the first group (n=36). In the second group (n=48), dexamethasone was administered in addition to fetal cortical tissue transplantation. The third group (n=16) was used as the surgical control group. The rats were allowed to live for 6 weeks and were then decapitated. The grafts were examined by electron microscopy. Additionally, quantitative analyses of the neurotransmitters and amino acids of the grafts were conducted using high-pressure liquid chromatography. Electron microscopic observations revealed that the grafts were still surviving at the end of the 6th week in both groups. However, in the group that received dexamethasone, neurons and their organelles were better developed than in the group that did not receive dexamethasone. Concommitantly, results of quantitative analysis in the dexamethasone group revealed statistically extremely significant higher amino acid values for glutamic acid, aspartic acid, beta-alanine, and lysine and significantly higher values for gamma-aminobutyric acid, glutamine, glycine, and serine when compared to the nondexamethasone group. Dexamethasone is effective in increasing the survival and in developing the ultrastructural and functional outcome of transplanted neurons in fetal grafts.