Molecules (Jun 2020)

Epigallocatechin-3-Gallate (EGCG), an Active Compound of Green Tea Attenuates Acute Lung Injury Regulating Macrophage Polarization and Krüpple-Like-Factor 4 (KLF4) Expression

  • Saleh A. Almatroodi,
  • Ahmad Almatroudi,
  • Mohammed A. Alsahli,
  • Mohammad A. Aljasir,
  • Mansoor Ali Syed,
  • Arshad Husain Rahmani

DOI
https://doi.org/10.3390/molecules25122853
Journal volume & issue
Vol. 25, no. 12
p. 2853

Abstract

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Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) are serious clinical complications with a high frequency of morbidity and mortality. The initiation and amplification of inflammation is a well-known aspect in the pathogenesis of ALI and related disorders. Therefore, inhibition of the inflammatory mediators could be an ideal approach to prevent ALI. Epigallocatechin-3-gallate (EGCG), a major constituent of green tea, has been shown to have protective effects on oxidative damage and anti-inflammation. The goal of the present study was to determine whether EGCG improves phenotype and macrophage polarisation in LPS-induced ALI. C57BL/6 mice were given two doses of EGCG (15 mg/kg) intraperitoneally (IP) 1 h before and 3 h after LPS instillation (2 mg/kg). EGCG treatment improved histopathological lesions, Total Leucocyte count (TLC), neutrophils infiltration, wet/dry ratio, total proteins and myeloperoxidase (MPO) activity in LPS-induced lung injury. The results displayed that EGCG reduced LPS-induced ALI as it modulates macrophage polarisation towards M2 status. Furthermore, EGCG also reduced the expression of proinflammatory M1 mediators iNOS TNF-α, IL-1β and IL-6 in the LPS administered lung microenvironment. In addition, it increased the expression of KLF4, Arg1 and ym1, known to augment the M2 phenotype of macrophages. EGCG also alleviated the expression of 8-OHdG, nitrotyrosine, showing its ability to inhibit oxidative damage. TREM1 in the lung tissue and improved lung regenerative capacity by enhancing Ki67, PCNA and Ang-1 protein expression. Together, these results proposed the protective properties of EGCG against LPS-induced ALI in may be attributed to the suppression of M1/M2 macrophages subtype ratio, KLF4 augmentation, lung cell regeneration and regulating oxidative damage in the LPS-induced murine ALI.

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