Role of Hydroalcoholic Extract of Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Agaricomycetes), in Facilitating Cellular Acclimatization in a Low-Oxygen Microenvironment

Ganoderma lucidum is known to exert many health benefits including effects to improve oxygen utilization. Therefore, this study was designed to evaluate the role of a hydroalcoholic G. lucidum extract in providing tolerance to HT22 cells grown under hypoxic conditions. HT22 cells were exposed to 0.5% O-2 in the presence or absence of the extract for 24 hours. At the end of the exposure period, we performed cell viability assays, cell cycle analysis, and biochemical and protein expression studies. The extract-treated cells revealed less cell death, minimized caspase 3 and reactive oxygen species levels, and relieved G(0)/G(1) cell cycle arrest compared with hypoxic cells cultured without the extract. Further, extract-treated cells showed unproved expression of Nrf2, heme oxygenase 1, and metallothionein and stabilized levels of hypoxia-inducible factor 1 alpha. Moreover, lower levels of nuclear factor-kappa B and tumor necrosis factor alpha were evident in extract-treated cells. Overall, the G. lucidum extract reduced hypoxia-induced cell death and augmented transcription factors (HIF-1 alpha and Nrf2), conferring tolerance to hypoxia.