Browsing by Author "Kirkim, G"

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    The Effect of Erythropoietin on S100 Protein Expression in Cochlea After Acoustic Overstimulation: An Experimental Study
    Gürgen, SG; Gürgen, O; Kirkim, G; Kolatan, HE; Gürkan, S; Eskiizmir, G
    Aim: To investigate the effect of Erythropoietin on acoustically overstimulated rat spiral ganglion neurons (SGNs) using S100 protein immunostaining. Material and Method: Twenty-two Wistar albino rats were divided into three groups: healthy control group (n= 7), Saline solution (n= 7) and Erythropoietin injection groups (n= 8). Saline solution and Erythropoietin injection groups received white noise (100 dB SPL) for 3 hours. Cochlear sections were stained by silver staining technique and immunostained by S100 antibody. Results: Histochemical analysis of silver staining sections revealed normal structure and a weak staining in SGNs of healthy control group. However, dark-black cytoplasmic staining, cellular shrinkage and degeneration were detected in saline injection group. On the other hand, a few weakly stained neurons were observed in erythropoietin injection group. S100 staining demonstrated strong reaction in Schwann cells and myelin sheaths of SGNs in healthy control group (p< 0.05). In saline solution injection group, Schwann cells showed moderate S100 reaction and other regions of SGNs showed weak reaction (p< 0.05). In erythropoietin injection group, strong S100 expression almost similar to the healthy control group was determined, although there was an occasional decrease. Discussion: Erythropoetin may prevent noise induced SGN degeneration via protecting the Schwann cells in rat cochlea.
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    Effect of Erythropoietin on Acoustically Traumatized Rat Cochlea An Immunohistochemical Study
    Gürgen, O; Gürgen, SG; Kirkim, G; Kolatan, E; Gürkan, S; Güvenç, Y; Eskiizmir, G
    OBJECTIVE: To investigate the audiological and histopathological effects of erythropoietin on acoustic over-stimulation in rats. STUDY DESIGN: Twenty-two male Wistar albino rats were divided into 3 groups: sham group (n = 7), erythropoietin injection group (n = 8), and saline injection group (n = 7). Both erythropoietin and saline injection groups were exposed to white noise (100 decibel [dB] sound pressure level (SPLD for 3 hours. Auditory brainstem responses were measured before, immediately after, and on the 7th day of noise exposure. All animals were sacrificed on the 7th day and temporal bones were collected. The serial sections of the cochleae were stained by caspase-3 and caspase-9 immunostaining and by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method in order to detect apoptotic cells. RESULTS: In the saline group statistically significant differences were detected between the baseline and immediate postacoustic overstimulation thresholds of click and 6 kHz stimuli. However, when the baseline and immediate postacoustic overstimulation thresholds of click and 6 kHz stimuli were compared in the erythropoietin injection group, no statistically significant difference was determined. Histo pathologic evaluations demonstrated that erythropoietin decreased the amount of apoptotic cells in the cochlea. CONCLUSION: Erythropoietin is likely to prevent the acute threshold changes and decrease the amount of apoptosis in cochlea after acoustic overstimulation in rats.