Dexamethasone and methylprednisolone do not inhibit neuritic outgrowth while inhibiting outgrowth of fibroblasts from spiral ganglion explants.
CONCLUSIONS
Dexamethasone and methylprednisolone do not inhibit neuritic outgrowth while inhibiting fibroblastic outgrowth from spiral ganglion micro-explants.


OBJECTIVE
To demonstrate reduced fibroblastic outgrowth while maintaining neurite outgrowth for several corticosteroids using an in vitro test system of neonatal rat spiral ganglion micro-explants.


METHODS
The in vitro test system comprised 3-day-old rat spiral ganglion micro-explants. Dexamethasone, methylprednisolone, triamcinolone acetonide, and human recombinant brain-derived neurotrophic factor (hrBDNF) were tested in vitro. The control was ganglion micro-explants in supplemented Dulbecco's modified Eagle's medium. Areas of the ganglion explant, neurite and fibroblast outgrowth of ganglion explants after 10 days in vitro were imaged, digitized, and analyzed using Image Tool 3.00 on a PC workstation. Areas of neurite and fibroblast outgrowth from the experimental explants were compared against values obtained from control explants.


RESULTS
Dexamethasone gave the best result of the three corticosteroids tested for inhibiting fibroblast outgrowth while not inhibiting neurite outgrowth from the ganglion micro-explants. Media containing hrBDNF (10 ng/ml) stimulated significantly greater neurite outgrowth than outgrowth from control explants (p < 0.001). Ganglion micro-explants treated with dexamethasone (0.02 mg/ml) and methylprednisolone (0.5 mg/ml) provided the greatest inhibition of fibroblast outgrowth compared with control explants (p < 0.001).
Furze
Alexis
A
Department of Otolaryngology, University of Miami Ear Institute, Miller School of Medicine, Miami, FL, USA.
Kralick
Deanna
D
Vakharia
Anand
A
Jaben
Korey
K
Graves
Reid
R
Adil
Eelam
E
Eshraghi
Adrien A
AA
Balkany
Thomas J
TJ
Van de Water
Thomas R
TR
D000818:Animals; D000831:Animals, Newborn; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects*; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000187:drug effects*; D007124:Immunoenzyme Techniques; D008775:Methylprednisolone / Q000494:pharmacology*; D016501:Neurites / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology; D013136:Spiral Ganglion / Q000187:drug effects*; D014222:Triamcinolone Acetonide / Q000494:pharmacology
D019208:Brain-Derived Neurotrophic Factor; D011994:Recombinant Proteins; D003907:Dexamethasone; D014222:Triamcinolone Acetonide; D008775:Methylprednisolone