2,4,6-Trihydroxy-3-geranyl acetophenone suppresses vascular leakage and leukocyte infiltration in lipopolysaccharide-induced endotoxemic mice

Abstract

Context

Lipopolysaccharide (LPS) exacerbates systemic inflammatory responses and causes excessive fluid leakage. 2,4,6-Trihydroxy-3-geranyl acetophenone (tHGA) has been revealed to protect against LPS-induced vascular inflammation and endothelial hyperpermeability in vitro.

Objective

This study assesses the in vivo protective effects of tHGA against LPS-induced systemic inflammation and vascular permeability in endotoxemic mice.

Materials and methods

BALB/c mice were intraperitoneally pre-treated with tHGA for 1 h, followed by 6 h of LPS induction. Evans blue permeability assay and leukocyte transmigration assay were performed in mice (n = 6) pre-treated with 2, 20 and 100 mg/kg tHGA. The effects of tHGA (20, 40 and 80 mg/kg) on LPS-induced serum TNF-α secretion, lung dysfunction and lethality were assessed using ELISA (n = 6), histopathological analysis (n = 6) and survivability assay (n = 10), respectively. Saline and dexamethasone were used as the negative control and drug control, respectively.

Results

tHGA significantly inhibited vascular permeability at 2, 20 and 100 mg/kg with percentage of inhibition of 48%, 85% and 86%, respectively, in comparison to the LPS control group (IC₅₀=3.964 mg/kg). Leukocyte infiltration was suppressed at 20 and 100 mg/kg doses with percentage of inhibition of 73% and 81%, respectively (IC₅₀=17.56 mg/kg). However, all tHGA doses (20, 40 and 80 mg/kg) failed to prevent endotoxemic mice from lethality because tHGA could not suppress TNF-α overproduction and organ dysfunction.

Discussion and conclusions

tHGA may be developed as a potential therapeutic agent for diseases related to uncontrolled vascular leakage by combining with other anti-inflammatory agents.

Keywords:

• tHGA
• LPS
• endothelial hyperpermeability
• vascular inflammation

Acknowledgements

The authors would like to thank the members of Cell Signaling Lab, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, for providing technical supports for this study. The authors also want to acknowledge Miss Audrey Kow Siew Foong for her kind contribution in proofreading the manuscript. Lastly, the authors would like to express utmost appreciation to Mr Liew Kong Yen for his guidance and assistance in statistical analyses.

Disclosure statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Additional information

Funding

This project was supported by the Ministry of Higher Education Malaysia under Fundamental Research Grant Scheme [FRGS/1/2013/SKK03/UPM/02/1] with the project code of 04-01-13-1195FR.