Macamide B Pretreatment Attenuates Neonatal Hypoxic-Ischemic Brain Damage of Mice Induced Apoptosis by Regulates Autophagy Via The PI3K/AKT Signaling Pathway

Abstract

Lepidium meyenii (Maca) is an annual or biennial herb from South America that is a member of the genus Lepidium L. in the family Cruciferae. This herb has antioxidant, anti-apoptotic, and enhances autophagy functions and can prevent cell death, and protect neurons from ischemic damage. Macamide B, an effective active ingredient of maca, has a neuroprotective role in neonatal hypoxic-ischemic brain damage (HIBD), and the underlying mechanism of its neuroprotective effect is not yet known. The purpose of this study is to explore the impact of macamide B on HIBD-induced autophagy and apoptosis and its potential mechanism for neuroprotection. The modified Rice-Vannucci method was used to induce HIBD on 7-day-old (P7) macamide B and vehicle-pretreated pups. TTC staining was used to evaluate the cerebral infarct volume of pups, brain water content was measured to evaluate the neurological function of pups, neurobehavioral testing was used to assess functional recovery after HIBD, TUNEL and FJC staining was used to detect cell autophagy and apoptosis, and western blot analysis was used to detect the expression levels of the pro-survival signaling pathway phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) and autophagy and the apoptosis-related proteins. The results show that macamide B pretreatment can significantly decrease brain damage, improve the recovery of neural function after HIBD. At the same time, macamide B pretreatment can induce the activation of PI3K/AKT signaling pathway after HIBD, enhance autophagy, and reduce hypoxic-ischemic (HI)-induced apoptosis. In addition, 3-methyladenine (3-MA), an inhibitor of PI3K/AKT signaling pathway, significantly inhibits the increase in autophagy levels, aggravates HI-induced apoptosis, and reverses the neuroprotective effect of macamide B on HIBD. Our data indicate that macamide B pretreatment might regulate autophagy through PI3K/AKT signaling pathway, thereby reducing HIBD-induced apoptosis and exerting neuroprotective effects on neonatal HIBD. Macamide B may become a new drug for the prevention and treatment of HIBD.