Examination of autologous and embryonic cortical brain tissue transplantation to adult brain cortex in rats

Restorative neurosurgery

Restorative neurosurgery currently is the frontier of neuroscientists for the restoration of lost neuronal function especially in neurodegenerative diseases and ischemic and traumatic central nervous system (CNS) disorders. The striking developments in molecular neurobiology and bio-technology are progressively offering new opportunities for a better quality of life to patients suffering from loss of neuronal function. Besides all new and challenging medical therapeutic interventions, great emphasis is also given to transplantation for neuronal restoration as well.

Neurotransmitter and amino acid analysis and ultrastructural observations of fetal brain cortex transplantation to adult rat brain under the effect of dexamethasone

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

Dexamethasone is effective in increasing the survival and in developing the ultrastructural and functional outcome of transplanted neurons in fetal grafts.

The effect of the pineal gland on liver regeneration in rats

BACKGROUND/AIMS

We investigated the influence of pinealectomy on liver regeneration after partial hepatectomy in rats.

METHODS

Thirty rats were allocated into four groups as follows: group 1 in which no operation was done (control), group 2 in which only midline scalp incision and craniotomy was performed (sham operation), group 3 in which pinealectomy was performed and group 4 in which the rats underwent pinealectomy and pineal transplantation. Eight weeks later all the rats underwent 70% hepatectomy.

RESULTS

Hepatic regenerative capacity was observed 24 h after PH by bromodeoxyuridine incorporation into DNA and the mitotic index of hepatocytes. The bromodeoxyuridine labeling indices were 45.4, 35.8, 19.9 and 36.8 in groups 1, 2, 3 and 4, respectively. The mitotic indices of the same groups were 31.2, 28.7, 8.3 and 13.4, respectively. Both the bromodeoxyuridine labeling and mitotic indices were significantly lower in the pinealectomized rats than in the control and sham operation groups.

CONCLUSIONS

These results suggest that the pineal gland stimulates liver regeneration after partial hepatectomy in rats.

Morphological assessment in pinealectomy and foetal pineal gland transplantation in rats: Part I

The effects of pineal gland, an endocrine organ known to affect the physiology of various organs and systems including the hypothalamo-hypophyseal axis, on the morphological characteristics of target organs were investigated in rats after pinealectomy and foetal pineal gland transplantation to a subpial cortical area close to the pinealectomized region. It was demonstrated that weight gain was significantly slower in pinealectomized male rats (p < 0.01); pituitary gland weight was lower in the pinealectomized group (p < 0.01) and transplantation had no effect on the weight of this organ; weight of adrenal gland and testis were lower after pinealectomy (p < 0.01) but restored back to control levels after transplantation; the mitotic activity in seminiferous tubules increased with pinealectomy and returned back to control indexes after transplantation. Research on hypothalamic catecholaminergic content revealed a diminished histofluorescence in pinealectomized rats which showed a potentiated restoration after transplantation. The innervation of the pineal gland was studied by anterograde and retrograde injections of Wheat Germ Agglutinin Horse Radish Peroxidase from superior cervical ganglion and pineal gland, respectively. It was demonstrated that cell bodies were traced both at the transplanted tissue and hypothalamus. In view of these data, the multifunctional and a probable high level homeostatic harmony regulator essence of pineal gland is discussed.

Behavioural assessment of pinealectomy and foetal pineal gland transplantation in rats: Part II

Pineal gland is an endocrine organ which exerts regulatory effects on the activity of various organs and systems. The present study was undertaken to highlight in experimental animals the possible integrative function of this endocrine organ on a behavioural pattern. Pinealectomy and foetal pineal gland transplantation to a subpial cortical area close to the pinealectomized region was performed. Behaviour was defined through motor activity induced by low (2 mg/kg) and high (10 mg/kg) doses of amphetamine in rats. It was shown that pinealectomy produced significant different patterns of behaviour induced by low and high doses of amphetamine. In sham operated animals low dose amphetamine induced a significant locomotor stimulation but without stereotyped activity. High dose amphetamine induced stereotyped activity. After pinealectomy even low dose amphetamine produced the behavioural pattern of stereotyped activity resembling a high dose amphetamine-induced behaviour. This differential effect of amphetamine, seen in pinealectomized rats, was completely restored after transplantation. On the other hand, melatonin treatment did not generate a significant alteration of behavioural profile either in the control or pinealectomized group of rats. Results are discussed with regard to the general regulatory function of the pineal gland.

Improved survival of transplanted cortical brain tissue grafts by iloprost in rats

The cytoprotective effect of iloprost on the viability and survival of embryonic cortical brain tissue grafts was examined ultrastructurally under light and electron microscopy before and 4 weeks after transplantation surgery. It was shown that neural grafts stored in iloprost solution (50 ng/mL) for 3 hours were more or less in a normal cytoarchitecture compared with saline-preserved grafts. Moreover, it was demonstrated that 4 weeks after transplantation, graft tissues stored in iloprost solution for 3 hours before implantation maintained a successful survival. Thus, a higher cellular population with new vascularization areas and preservation of myelin formation were accepted as a desirable integration of the graft tissue into the host brain tissue. The mechanism of action of iloprost is discussed.