신생 흰쥐 해마 절편 배양에서 산소-포도당 박탈에 의한 신경 세포 사망에 대한 성장호르몬의 효과 = Effect of growth hormone on neuronal death in hippocampal slice cultures of neonatal rats exposed to oxygen-glucose deprivation

다국어 초록 (Multilingual Abstract)

Purpose : To investigate whether growth hormone (GH) has a protective effect on neurons in hippocampal slice cultures of neonatal rats exposed to oxygen-glucose deprivation (OGD).
Methods : Cultured hippocampal slices of 7-day-old rats were exposed to OGD for 60 min. Then, the slices were immediately treated with three doses of GH (5, 50, or 500 µM) in media. The relative fluorescent densities of propidium iodide (PI) uptake in the slices and relative lactate dehydrogenase (LDH) activities in the media were determined and compared between each GH- treated group of slices and untreated slices (control) at 12 and 24 h after OGD. Immunofluorescent staining for caspase-3 and TUNEL staining were performed to observe the effect of GH on apoptotic neuronal death.
Results : The relative fluorescent densities of PI uptake in CA1 and dentate gyrus (DG) of the hippocampal slices in each GH-treated group were not significantly different from those in the untreated slices at 12 and 24 h after OGD (P＞0.05). Treatment with GH could reduce the relative LDH activities in the media of the GH-treated groups only at 12 h after OGD (P＜0.05). Expression of caspase-3 and TUNEL positivity in CA1 and DG of the slices treated with 50-ìM GH were not different from those of the untreated slices at 12 and 24 h after OGD.
Conclusion : Treatment of hippocampal slice cultures with GH after OGD does not show a definitive protective effect on neuronal death but can reduce the LDH efflux of the slices in media at 12 h after OGD.

국문 초록 (Abstract)

목 적 : 산소-포도당 박탈(oxygen-glucose deprivation, OGD)에 노출된 신생 흰쥐 해마 절편에서 성장호르몬이 신경 세포 보호 효과가 있는지를 연구하고자 하였다.
방 법 : 배양된 생후 7일된 신생 흰쥐의 해마 절편을 OGD에 60분간 노출 시켰다. 이후 각기 다른 세 용량의 성장 호르몬(5, 50, 500 µM)을 배양액에 투여하고 OGD 노출 후 12 와 24시간에 해마 절편의 상대적 propidium iodide (PI) uptake와 배양액의 상대적 lactate dehydrogenase (LDH) 활성도를 측정하여 성장 호르몬 처치군과 성장 호르몬 처치하지 않은 대조군 사이에 비교하였다. 신경 세포의 세포 사멸에 대한 성장호르몬의 효과를 관찰하고자 caspase-3의 면역 형광 염색과 TUNEL 염색을 시행하였다.
결 과 : 1) 각기 다른 세 용량의 성장호르몬을 처치한 해마 절편의 CA1과 DG에서 상대적 PI uptake는 처치하지 않은 대조군에 비해 OGD 노출 후 12시간과 24시간에 의미 있는 차이를 보이지 않았다(P＞0.05). 2) 상대적 LDH 활성도는 OGD 노출 후 12시간에만 성장 호르몬을 투여한 군의 배양액에서 대조군에 비해 통계적으로 의미 있게 감소하였다(P＜0.05). 3) 성장 호르몬(50 µM)으로 처치한 해마 절편의 CA1과 DG에서 caspase-3 발현과 TUNEL 양성의 발현은 OGD 노출 후 12와 24시간에 대조군과 차이를 보이지 않았다.
결 론 : OGD에 노출된 해마 절편에서 성장호르몬 처치는 확실한 신경세포 보호 효과를 보이지 않았으나 OGD 노출 후 12시간에 배양액으로 LDH 유출을 감소시킬 수 있었다.

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