Role of mitophagy in neonatal rats with hypoxic-ischemic brain damage

LI Ming-Xi, QU Yi, MU De-Zhi

Chinese Journal of Contemporary Pediatrics ›› 2017, Vol. 19 ›› Issue (2) : 242-249.

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Chinese Journal of Contemporary Pediatrics ›› 2017, Vol. 19 ›› Issue (2) : 242-249. DOI: 10.7499/j.issn.1008-8830.2017.02.021
EXPERIMENTAL RESEARCH

Role of mitophagy in neonatal rats with hypoxic-ischemic brain damage

  • LI Ming-Xi, QU Yi, MU De-Zhi
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Abstract

Objective To investigate mitophagy in an animal model of hypoxic-ischemic brain damage (HIBD) and its role in HIBD. Methods A total of 120 neonatal Sprague-Dawley rats aged 7 days were divided into three groups: sham-operation, HIBD, and autophagy inhibitor intervention (3MA group). The rats in the HIBD group were treated with right common carotid artery ligation and then put in a hypoxic chamber (8% oxygen and 92% nitrogen) for 2.5 hours. Those in the 3MA group were given ligation and hypoxic treatment at 30 minutes after intraperitoneal injection of 2 μL 3MA. Those in the sham-operation group were not given ligation or hypoxic treatment. Single cell suspension was obtained from all groups after model establishment. Immunofluorescence localization was performed for mitochondria labeled with MitoTracker, autophagosomes labeled with LysoTracker, and autophagy labeled with LC3 to observe mitophagy. After staining with the fluorescent probe JC-1, flow cytometry was used to measure mitochondrial membrane potential. TTC staining was used to measure infarct volume. Cytoplasmic proteins in cortical neurons were extracted, and Western blot was used to measure the expression of mitophagy-related proteins. Results Compared with the shamoperation group, the HIBD group had a significant reduction in mitochondrial membrane potential (P < 0.05), a significant increase in mitophagy (P < 0.05), a significant increase in the expression of the proteins associated with the division of the mitochondrial Drp1 and Fis1 (P < 0.05), and a significant reduction in the expression of the mitochondrial outer membrane protein Tom20 and the mitochondrial inner membrane protein Tim23 (P < 0.05). Compared with the HIBD group, the 3MA group had a significantly greater reduction in mitochondrial membrane potential (P < 0.05), but showed significantly reduced mitophagy (P < 0.05). In addition, the 3MA group had a significantly increased degree of cerebral infarction compared with the HIBD group (P < 0.05). Conclusions HIBD can increase the degree of mitophagy, and the inhibition of mitophagy can aggravate HIBD in neonatal rats.

Key words

Mitophagy / Hypoxic-ischemic brain damage / Neonatal rats

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LI Ming-Xi, QU Yi, MU De-Zhi. Role of mitophagy in neonatal rats with hypoxic-ischemic brain damage[J]. Chinese Journal of Contemporary Pediatrics. 2017, 19(2): 242-249 https://doi.org/10.7499/j.issn.1008-8830.2017.02.021

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