Effects of propofol and its formulation components on macrophages and neutrophils in obese and lean animals

Abstract

We hypothesized whether propofol or active propofol component (2,6-diisopropylphenol [DIPPH] and lipid excipient [LIP-EXC]) separately may alter inflammatory mediators expressed by macrophages and neutrophils in lean and obese rats. Male Wistar rats (n = 10) were randomly assigned to receive a standard (lean) or obesity-inducing diet (obese) for 12 weeks. Animals were euthanized, and alveolar macrophages and neutrophils from lean and obese animals were exposed to propofol (50 µM), active propofol component (50 µM, 2,6-DIPPH), and lipid excipient (soybean oil, purified egg phospholipid, and glycerol) for 1 h. The primary outcome was IL-6 expression after propofol and its components exposure by alveolar macrophages extracted from bronchoalveolar lavage fluid. The secondary outcomes were the production of mediators released by macrophages from adipose tissue, and neutrophils from lung and adipose tissues, and neutrophil migration. IL-6 increased after the exposure to both propofol (median [interquartile range] 4.14[1.95-5.20]; p = .04) and its active component (2,6-DIPPH) (4.09[1.67-5.91]; p = .04) in alveolar macrophages from obese animals. However, only 2,6-DIPPH increased IL-10 expression (7.59[6.28-12.95]; p = .001) in adipose tissue-derived macrophages. Additionally, 2,6-DIPPH increased C-X-C chemokine receptor 2 and 4 (CXCR2 and CXCR4, respectively) in lung (10.08[8.23-29.01]; p = .02; 1.55[1.49-3.43]; p = .02) and adipose tissues (8.78[4.15-11.57]; p = .03; 2.86[2.17-3.71]; p = .01), as well as improved lung-derived neutrophil migration (28.00[-3.42 to 45.07]; p = .001). In obesity, the active component of propofol affected both the M1 and M2 markers as well as neutrophils in both alveolar and adipose tissue cells, suggesting that lipid excipient may hinder the effects of active propofol.

Keywords: adipose tissue; inflammation; lung; macrophages; neutrophils; obesity; propofol.

FIGURE 1

Alveolar and adipose tissue macrophages from obese animals (n = 5). Gene expression of interleukin (IL)‐6 (A, C) and inducible nitric oxide synthase (iNOS) (B, D) was assessed by reverse transcription polymerase chain reaction in macrophages stimulated for 1 h with propofol composition (2,6‐diisopropylphenol [2,6‐DIPPH] + lipid excipient [LIP‐EXC]), active propofol component (2,6‐DIPPH), or LIP‐EXC. Data represent relative gene expression calculated as a ratio of the average expression of the target gene compared with the reference gene 36B4 and expressed as fold change relative to unstimulated cells. Samples were measured in triplicate; values are depicted as box plots (median, interquartile range, and minimum and maximum). Comparisons between groups were performed using the Kruskal–Wallis test followed by Dunn's post‐hoc test. BALF, bronchoalveolar lavage fluid

FIGURE 2

Alveolar and adipose tissue macrophages from obese animals (n = 5). Gene expression of interleukin (IL)‐10 (A, D); transforming growth factor beta (TGF‐β; B, E); and arginase (C, F) was assessed by reverse transcription polymerase chain reaction in macrophages stimulated for 1 h with the propofol composition (2,6‐diisopropylphenol [2,6‐DIPPH] +lipid excipient [LIP‐EXC]), active propofol component (2,6‐DIPPH), or LIP‐EXC. Data represent relative gene expression calculated as a ratio of the average expression of the target gene compared with the reference gene 36B4 and expressed as fold change relative to unstimulated cells. Samples were measured in triplicate; values are depicted as box plots (median, interquartile range, and minimum and maximum). Comparisons between groups were performed using the Kruskal–Wallis test followed by Dunn's post‐hoc test. BALF, bronchoalveolar lavage fluid

FIGURE 3

Neutrophils in lung tissue and adipose tissue from obese animals (n = 5). Gene expression of CXCR2 (A, C) and CXCR4 (B, D) was assessed by reverse transcription polymerase chain reaction in neutrophils stimulated for 1 h with the propofol composition (2,6‐diisopropylphenol [2,6‐DIPPH] + lipid excipient [LIP‐EXC]), active propofol component (2,6‐DIPPH), or (LIP‐EXC). Data represent relative gene expression calculated as a ratio of the average expression of the target gene compared with the reference gene 36B4 and expressed as fold change relative to unstimulated cells. Samples were measured in triplicate; values are depicted as box plots (median, interquartile range, and minimum and maximum). Comparisons between groups were performed using the Kruskal–Wallis test followed by Dunn's post‐hoc test

FIGURE 4

Percentage increase in neutrophil migration from lung (A) and adipose (B) tissue of obese animals (n = 4) stimulated for 1 h with the propofol composition (2,6‐diisopropylphenol [2,6‐DIPPH] +lipid excipient [LIP‐EXC]), active propofol component (2,6‐DIPPH), or LIP‐EXC in the top compartments of a chemotaxis chamber. Migrated neutrophils in response to cytokine‐induced neutrophil attracting chemokine (KC, 0.1 µg/ml) were counted after 60 min. Samples were measured in triplicate; values are the percentage variation related to saline control group cells (median, interquartile range, and minimum and maximum) of four animals/group