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Effects of salidroside on the secretion of inflammatory mediators induced by lipopolysaccharide in the co-culture of rat alveolar macrophages and type II alveolar epithelial cells

CAI Yan-Chun¹, HUANG Qian², WEI Xiao-Li¹, MEI Ru-Huan¹, SA Li-Na¹, HU Xiao-Lan^1,*

¹Department of Physiology, School of Medicine, Zhejiang University, Hangzhou 310058, China；²he First Affiliated Hospital, Zhejiang University, Hangzhou 310006, China

Abstract

The aim of the present study was to investigate the effect of salidroside (Sal) on inflammatory activation induced by lipopolysaccharide (LPS) in the co-culture of rat alveolar macrophages (AM) NR 8383 and type II alveolar epithelial cells (AEC II) RLE-6TN. CCK-8 colorimetric method was used to detect cell proliferation percentage. The enzyme-linked immunosorbent assay (ELISA) was used to determine the content of tumor necrosis factor alpha (TNF-α), macrophage inflammatory protein-2 (MIP-2) and interleukin-10 (IL-10) in the supernatant. Western blot was used to examine the expression levels of phosphorylated AKT (p-AKT) and total AKT protein. The results showed that pretreatment of RLE-6TN cells or co-culture of RLE-6TN and NR 8383 cells with 32 and 128 µg/mL Sal for 1 h, followed by continuous culture for 24 h, significantly increased the cell proliferation (P < 0.05). Compared with control group, 32 and 128 µg/mL Sal pretreatment significantly increased the ratio of p-AKT/AKT in RLE-6TN cells (P < 0.05). Pretreatment of 32 µg/mL Sal not only inhibited the secretion of TNF-α and MIP-2 by NR 8383 cells induced by LPS (P < 0.05), but also enhanced the inhibitory effect of RLE-6TN and NR 8383 cells co-culture on the secretion of TNF-α and MIP-2 by NR 8383 cells induced by LPS (P < 0.05). In addition, 32 µg/mL Sal pretreatment promoted LPS-induced IL-10 secretion by NR 8383 cells (P < 0.05), and enhanced the promoting effect of co-culture of RLE-6TN and NR 8383 cells on the IL-10 secretion by LPS-induced NR 8383 cells (P < 0.05). In conclusion, Sal may directly inhibit LPS-induced inflammatory activation of AM (NR 8383), promote the proliferation of AEC II (RLE-6TN) through PI3K/AKT signaling pathway, and enhance the regulatory effect of AEC II on LPS-induced inflammatory activation of AM.

Key words: salidroside; lipopolysaccharide; alveolar macrophages; type II alveolar epithelial cells

Received: 2018-11-18　　Accepted: 2019-03-12

Corresponding author: 胡晓兰　　E-mail: huxiaolan@zju.edu.cn

DOI: 10.13294/j.aps.2019.0024

Citing This Article：

CAI Yan-Chun, HUANG Qian, WEI Xiao-Li, MEI Ru-Huan, SA Li-Na, HU Xiao-Lan. Effects of salidroside on the secretion of inflammatory mediators induced by lipopolysaccharide in the co-culture of rat alveolar macrophages and type II alveolar epithelial cells. Acta Physiol Sin 2019; 71 (4): 575-580 (in Chinese with English abstract).