Experimental hyperthyroidism increases the effectiveness of predegenerated peripheral nerve graft implantation into hippocampus of adult rats.
OBJECTIVE
The aim of the study was to ascertain whether experimental hyperthyroidism changes the neurotrophic activity of 14- and 21-day-predegenerated peripheral nerve grafts towards CNS neurites.


METHODS
Hyperthyroidism was induced by subcutaneous injections of T_4. Autologous peripheral nerve grafts were implanted into the hippocampus of both euthyrotic and hyperthyrotic animals 14 or 21 days after sciatic nerve transection (groups ET14, Et21, Ht14 and Ht21, respectively). Non-predegenerated grafts were used as a control group (groups EtN adn HtN). Cells extending their neurites into the grafts were traced with FITC-HRP.


RESULTS
The number of traced cells in individual groups was as follows: EtN - 39.4 +/- 9.46, Et14 - 1 +/- 0.94, Et21 - 0.6 +/- 0.69; HtN - 95 +/- 19.46; Ht14 - 95.94 +/- 16.3, Ht21 - 99.94 +/- 7.26.


CONCLUSIONS
We found that experimentally induced hyperthyroidism strongly enhanced the regeneration of injured hippocampal neurites after implantation of peripheral nerve grafts that were practically inactive in euthyrotic animals.
Lewin-Kowalik
Joanna
J
Department of Physiology, Medical University of Silesia, Katowice, Poland. fzjkarpl@infomed.slam.katowice.pl
Gołka
Beata
B
Larysz-Brysz
Magdalena
M
Swiech-Sabuda
Ewa
E
Granek
Arkadiusz
A
D000818:Animals; D001930:Brain Injuries / Q000601:surgery*; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D016650:Fluorescein-5-isothiocyanate; D006085:Graft Survival / Q000502:physiology*; D006624:Hippocampus / Q000293:injuries / Q000378:metabolism / Q000601:surgery; D006735:Horseradish Peroxidase; D006980:Hyperthyroidism / Q000139:chemically induced / Q000378:metabolism; D008297:Male; D009414:Nerve Growth Factors / Q000378:metabolism; D009416:Nerve Regeneration / Q000502:physiology*; D016501:Neurites / Q000378:metabolism / Q000648:ultrastructure; D010525:Peripheral Nerves / Q000378:metabolism / Q000637:transplantation*; D051381:Rats; D017208:Rats, Wistar; D011988:Receptors, Thyroid Hormone / Q000378:metabolism; D013963:Thyroid Hormones / Q000378:metabolism* / Q000494:pharmacology; D013974:Thyroxine / Q000378:metabolism / Q000494:pharmacology; D016378:Tissue Transplantation / Q000379:methods*; D015854:Up-Regulation / Q000502:physiology
D009414:Nerve Growth Factors; D011988:Receptors, Thyroid Hormone; D013963:Thyroid Hormones; D006735:Horseradish Peroxidase; D016650:Fluorescein-5-isothiocyanate; D013974:Thyroxine