[Neurotrophic factors of the GDNF family and their receptors are detectable in spiral ganglion cells of normal hearing as well as of deafened rats].
BACKGROUND
Recent studies have shown that neurotrophic factors like BDNF, NT-3 and GDNF induce protective effects on spiral ganglion cells after noise- or drug-induced hearing loss. According to these studies it is suggested that deafness leads to a lack of neurotrophic factor or relating receptor expression in spiral ganglion cells, that has to be compensated by local cochlear application of these factors.


METHODS
In the present study we examined the expression pattern of members of the GDNF family (GDNF, Neurturin, Artemin, Persephin) and their relating receptors (Ret, GFRalpha1 - 3) as well as BDNF and trkB on spiral ganglion cells of normal hearing and experimentally deafened rats (10 % neomycine). Indirect immunofluorescence was carried out to determine protein expression of these factors and their receptors 26 days following deafening.


RESULTS
Our results demonstrate neurotrophic factor and receptor expression on spiral ganglion cells of normal hearing as well as experimentally deafened animals.


CONCLUSIONS
Our data indicate that within a period of 26 days after deafening no detectable reduction of the GDNF-family member expression and their receptors was ascertainable on spiral ganglion cells by immunohistochemistry. Thus, a lack of neurotrophic factor expression is unlikely to be the only cause of spiral ganglion cell loss following deafening.
Wefstaedt
P
P
Hals-Nasen-Ohrenklinik der Medizinischen Hochschule Hannover.
Scheper
V
V
Rieger
H
H
Lenarz
T
T
Stöver
T
T
D000818:Animals; D003638:Deafness / Q000473:pathology*; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000032:analysis*; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors / Q000032:analysis*; D008297:Male; D008856:Microscopy, Fluorescence; D009414:Nerve Growth Factors / Q000032:analysis*; D051381:Rats; D011917:Rats, Inbred Lew; D017475:Receptors, Nerve Growth Factor / Q000032:analysis*; D012016:Reference Values; D013136:Spiral Ganglion / Q000473:pathology*
D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D009414:Nerve Growth Factors; D017475:Receptors, Nerve Growth Factor