AUTHOR=Mondoñedo Jarred R. , Bartolák-Suki Elizabeth , Bou Jawde Samer , Nelson Kara , Cao Kun , Sonnenberg Adam , Obrochta Walter Patrick , Imsirovic Jasmin , Ram-Mohan Sumati , Krishnan Ramaswamy , Suki Béla 

TITLE=A High-Throughput System for Cyclic Stretching of Precision-Cut Lung Slices During Acute Cigarette Smoke Extract Exposure

JOURNAL=Frontiers in Physiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2020.00566

DOI=10.3389/fphys.2020.00566

ISSN=1664-042X

ABSTRACT=<sec><title>Rationale</title><p>Precision-cut lung slices (PCLSs) are a valuable tool in studying tissue responses to an acute exposure; however, cyclic stretching may be necessary to recapitulate physiologic, tidal breathing conditions.</p></sec><sec><title>Objectives</title><p>To develop a multi-well stretcher and characterize the PCLS response following acute exposure to cigarette smoke extract (CSE).</p></sec><sec><title>Methods</title><p>A 12-well stretching device was designed, built, and calibrated. PCLS were obtained from male Sprague-Dawley rats (<italic>N</italic> = 10) and assigned to one of three groups: 0% (unstretched), 5% peak-to-peak amplitude (low-stretch), and 5% peak-to-peak amplitude superimposed on 10% static stretch (high-stretch). Lung slices were cyclically stretched for 12 h with or without CSE in the media. Levels of Interleukin-1β (IL-1β), matrix metalloproteinase (MMP)-1 and its tissue inhibitor (TIMP1), and membrane type-MMP (MT1-MMP) were assessed via western blot from tissue homogenate.</p></sec><sec><title>Results</title><p>The stretcher system produced nearly identical normal Lagrangian strains (<italic>E</italic><sub><italic>xx</italic></sub> and <italic>E</italic><sub><italic>yy</italic></sub>, <italic>p</italic> &gt; 0.999) with negligible shear strain (<italic>E</italic><sub><italic>xy</italic></sub> &lt; 0.0005) and low intra-well variability 0.127 ± 0.073%. CSE dose response curve was well characterized by a four-parameter logistic model (<italic>R</italic><sup>2</sup> = 0.893), yielding an IC<sub>50</sub> value of 0.018 cig/mL. Cyclic stretching for 12 h did not decrease PCLS viability. Two-way ANOVA detected a significant interaction between CSE and stretch pattern for IL-1β (<italic>p</italic> = 0.017), MMP-1, TIMP1, and MT1-MMP (<italic>p</italic> &lt; 0.001).</p></sec><sec><title>Conclusion</title><p>This platform is capable of high-throughput testing of an acute exposure under tightly-regulated, cyclic stretching conditions. We conclude that the acute mechano-inflammatory response to CSE exhibits complex, stretch-dependence in the PCLS.</p></sec>