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=Volume 11 - 2020

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=Rationale:  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.
Objectives:  To develop a multi-well stretcher and characterize the PCLS response following acute exposure to cigarette smoke extract (CSE).
Methods:  A 12-well stretching device was designed, built, and calibrated.  PCLS were obtained from male Sprague-Dawley rats (N=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-1 (IL-1), matrix metalloproteinase (MMP)-1 and its tissue inhibitor (TIMP1), and membrane type-MMP (MT1-MMP) were assessed via western blot from tissue homogenate.
Results:  The stretcher system produced nearly identical normal Lagrangian strains (E_xx and E_yy, ρ>0.999) with negligible shear strain (E_xy<0.0005) and low intra-well variability 0.1270.073%.  CSE dose response curve was well characterized by a four-parameter logistic model (R2=0.893), yielding an IC¬50 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-1 (p=0.017), MMP-1, TIMP1, and MT1-MMP (p<0.001).
Conclusions:  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.