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Updated: May 21, 2026
Bronchoalveolar Lavage Exosomes in Lipopolysaccharide-induced Septic Lung Injury
Published on: May 21, 2018
[Expression and effects of microRNA-155 in the livers of septic mice]
Zhong-hua Wang1, Yan-bing Liang, Hao Tang
1Department of General Internal Medicine, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou510080, Guangdong, China.
Objective:
To evaluate the effects of microRNA-155 (miR-155) on liver injury in mice with sepsis.
Methods:
One hundred and twenty BALB/c mice were randomly divided into two groups of equal number according to random number table. Sepsis was induced by intraperitoneal injection of lipopolysaccharide (LPS,20 mg/kg). The mice were sacrificed at the time-points of 0, 2, 6, 12, 24, 48 hours. Blood and liver tissue were collected, and the levels of tumor necrosis factor- α (TNF- α ), interleukin (IL-6, IL-10) in serum and liver homogenate and alanine transaminase (ALT) in serum were determined by enzyme linked immunosorbent assay(ELISA). The injury of liver tissue was evaluated by histopathology. The expression of miR-155 in liver tissue was assessed by fluorescent quantitation reverse transcription-polymerase chain reaction (RT-PCR).
Results:
The levels of TNF- α , IL-6 and IL-10 in serum and liver homogenate of septic mice increased with passage of time, and then the levels of TNF-α and IL-6 lowered after reaching the peak value, but remained higher than that of control group.TNF-α (ng/L) reached the peak value at 2 hours post-LPS-injection (serum: 1538.46 ± 102.12 vs. 64.52 ± 18.44,liver homogenate: 255.26 ± 41.23 vs. 60.21 + 13.55, both P<0.05). The level of IL-6 (μg/L) reached the peak value at 6 hours post-LPS-injection (serum: 875.33 ± 102.37 vs. 153.72 ± 20.67, liver homogenate: 9.22 + 0.82 vs. 3.35 ±0.36, both P<0.05), and that of IL-10 (ng/L) reached the peak value at 48 hours post-LPS-injection (serum: 520.13 ± 88.52 vs. 23.43 3.01, liver homogenate: 260.12 + 50.38 vs. 16.37 ± 3.71, both P<0.05). There were significant differences in above indexes between septic and control group (all P<0.05). The serum level of ALT (U/L) rose with passage of time, reaching the peak value at 48 hours post-LPS-injection (603.26 + 70.21 vs. 45.84 + 5.64, P<0.05). The values showed significant differences between septic and control group (P<0.05). A large number of leucocytic infiltration was found in liver. Hepatic tissue showed architectural distortion. Hepatocyte vacuolation and nodular necrosis were obvious at 12 hours post-LPS-injection. Relative expression of miR-155 was found to be increased at 2 hours post-LPS-injection, reaching its peak value at 12 hours post-LPS-injection [(72.96 ± 9.34)-fold of control group, P<0.05].
Conclusion:
The increase in miR-155 expression might play an important role in the mechanism of liver injury during sepsis.
Insights
Increased microRNA-155 (miR-155) expression correlates with liver injury in sepsis models. This suggests miR-155 may be a key factor in sepsis-induced liver damage, offering potential therapeutic targets.
Area of Science:
- Molecular Biology
- Immunology
- Pathology
Context:
- Sepsis is a life-threatening condition characterized by a dysregulated host response to infection.
- Liver injury is a common and severe complication of sepsis, contributing to high mortality rates.
- MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression and are implicated in various disease processes.
Purpose:
- To investigate the role of microRNA-155 (miR-155) in the development of liver injury during sepsis in a mouse model.
- To assess the correlation between miR-155 expression levels and indicators of liver damage and inflammation.
Summary:
- Sepsis was induced in BALB/c mice using lipopolysaccharide (LPS).
- Levels of inflammatory cytokines (TNF-α, IL-6, IL-10), alanine transaminase (ALT), and miR-155 expression were measured over time.
- Histopathological analysis revealed significant liver tissue damage, including inflammatory infiltration and necrosis, in septic mice.
Impact:
- Results indicate a significant increase in miR-155 expression in the liver following LPS-induced sepsis, peaking at 12 hours.
- Elevated miR-155 levels were observed concurrently with increased inflammatory markers and liver injury indicators.
- The findings suggest that miR-155 upregulation plays a crucial role in the pathogenesis of sepsis-induced liver injury.
