Evaluation of apoptotic cell death following transient maternal hypotension in fetal rat brain: temporal pattern within the first 24 h after procedure

Authors: SİBEL BAYRAK, BİLGE PEHLİVANOĞLU, AYŞE MELTEM SEVGİLİ, ZEYNEP DİCLE BALKANCI, HAMİT ÖZYÜREK, PERGİN ATİLLA, AYŞE NUR ÇAKAR, FATMA BANU ANLAR

Abstract: To explore the effects of maternal transient systemic hypotension on apoptotic neuronal death in an intrauterine fetal rat brain during the first 24 h after induction of hypotension. Materials and methods: A total of 40 pregnant Sprague–Dawley rats were subjected to either transient systemic hypotension produced for 30 min by blood withdrawal via femoral artery catheterization (hypotension group) or sham operation (control group) on day 15. Two randomly selected fetuses were taken from each rat at 0, 6, 12, and 24 h after the procedure. Apoptosis was evaluated in sections from the whole fetal brain by TUNEL and caspase-3 staining. Results: TUNEL (+) and caspase (+) cells were detected only on the walls of the ventricles of both groups and more abundantly in the hypotension groups than in the control groups at all time points (P < 0.05). The increase in TUNEL (+) and caspase (+) cells was highest at 12 h (P < 0.05) following hypotension compared to the other hypotension groups. Conclusion: Maternal transient systemic hypotension caused the hypoxia–ischemia (HI)-induced death of immature neurons by apoptosis, and this is especially prominent at 12 h after the insult. Determination of the susceptibility of a developing brain to HI at a certain time may have potential significance on the timing of neuroprotective measures.

Keywords: Hypoxic ischemic injury, fetal rat brain, apoptosis, caspase-3, pregnancy, transient systemic hypotension

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