A Device for measuring the in-situ response of Human Bronchial Epithelial Cells to airborne environmental agents

Lakshmana D Chandrala,Yury Ronzhes,Kirsten Koehler,Kristine Nishida,Venkataramana K Sidhaye,Nima Afshar-Mohajer,Joseph Katz

doi:10.1038/s41598-019-43784-5

Lakshmana D Chandrala, Yury Ronzhes + Show 5 more

Open Access

https://doi.org/10.1038/s41598-019-43784-5

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Abstract

Measuring the time evolution of response of Normal Human Bronchial Epithelial (NHBE) cells to aerosols is essential for understanding the pathogenesis of airway disease. This study introduces a novel Real-Time Examination of Cell Exposure (RTECE) system, which enables direct in situ assessment of functional responses of the cell culture during and following exposure to environmental agents. Included are cell morphology, migration, and specialised responses, such as ciliary beat frequency (CBF). Utilising annular nozzles for aerosol injection and installing windows above and below the culture, the cells can be illuminated and examined during exposure. The performance of RTECE is compared to that of the commercial Vitrocell by exposing NHBE cells to cigarette smoke. Both systems show the same mass deposition and similar trends in smoke-induced changes to monolayer permeability, CBF and transepithelial resistance. In situ measurements performed during and after two exposures to smoke show that the CBF decreases gradually during both exposures, recovering after the first, but decreasing sharply after the second. Using Particle image velocimetry, the cell motions are monitored for twelve hours. Exposure to smoke increases the spatially-averaged cell velocity by an order of magnitude. The relative motion between cells peaks shortly after each exposure, but remains elevated and even increases further several hours later.

Highlights

Environmental exposure to airborne particulate matter has been associated with a variety of long-term respiratory diseases[1,2,3,4]
The present study introduces a novel exposure chamber for Real-Time Examination of Cell Exposure (RTECE) that enables in-situ live imaging of cell cultures while being exposed to airborne materials under controlled conditions
To demonstrate the capability of this system, a confluent monolayer of Normal Human Bronchial Epithelial (NHBE) cells are subjected to two exposures separated by a rest period of 60 min, each consisting of two cigarettes

Summary

Introduction

Environmental exposure to airborne particulate matter has been associated with a variety of long-term respiratory diseases[1,2,3,4]. A complete direct exposure system generally consists of an aerosol generation and dilution unit, and an exposure chamber, which houses the cell culture Several such systems have been developed and standardised over the years for toxicity testing of airborne particles[7,14]. In previous studies involving Madin–Darby canine kidney cells, the relative motions have been measured under a microscope to characterise the progression of a model wound in an epithelial monolayer[31]. They show that the cells migrate collectively towards the center of the wound to form a confluent layer.

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