Cigarette Smoke Exposure in Mice using a Whole-Body Inhalation System

Summary

This protocol demonstrates the study of the pathophysiologic effects of cigarette smoke (CS) with a whole-body inhalation (WBI) exposure system (WBIS) built in-house. This system can expose animals to CS under controlled repeatable conditions for research of CS-mediated effects on lung emphysema and hematopoiesis.

Abstract

Close to 14% of adults in the United States were reported to smoke cigarettes in 2018. The effects of cigarette smoke (CS) on lungs and cardiovascular diseases have been widely studied, however, the impact of CS in other tissues and organs such as blood and bone marrow remain incompletely defined. Finding the appropriate system to study the effects of CS in rodents can be prohibitively expensive and require the purchase of commercially available systems. Thus, we set out to build an affordable, reliable, and versatile system to study the pathologic effects of CS in mice. This whole-body inhalation exposure system (WBIS) set-up mimics the breathing and puffing of cigarettes by alternating exposure to CS and clean air. Here we show that this do-it-yourself (DIY) system induces airway inflammation and lung emphysema in mice after 4-months of cigarette smoke exposure. The effects of whole-body inhalation (WBI) of CS on hematopoietic stem and progenitor cells (HSPCs) in the bone marrow using this apparatus are also shown.

Introduction

Cigarette smoking remains one of the major causes of preventable diseases in the US despite the steady decline in the number of cigarette-smoking adults in the past 50–60 years¹. It is widely known that smoking is linked to multiple diseases of the lungs and blood including chronic obstructive pulmonary disease (COPD), a group of diseases that includes emphysema and chronic bronchitis^2,3,4. According to the Center for Disease Control (CDC), in 2014, COPD was the third leading cause of death in the United States with over 15 million Americans suff....

Protocol

All the animals involved in the experiments and the development of this technique have been under our animal use protocol approved by the Institutional Animal Care and Use Committee (IACUC) and under Baylor College of Medicine and MD Anderson institutions that are accredited by the Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC).

1. Building the apparatus

1. Assembling the air compressor with the valve system.
   1. Connect the fl.......

Discussion

Here we provide the information required for the construction of an apparatus for WBIS of mice to CS. After installation of the system, it is critically important that investigators calibrate the system based on the delivered dose of nicotine or cotinine in animals. The apparatus contains a timer and pressure gauges that can be used to adjust cigarette puff volume, puff frequency, combined smoke exposure period, and rest intervals that animals receive between each cigarette. Furthermore, the actual number of cigarettes a.......

Materials

Name	Company	Catalog Number	Comments
1 in fastener	Lowes	756990
1/4 in Barbed Y connector	VWR	89093-282
1/4 in straight tubing connector	VWR	62866-378
1/8 hex nipple	Lowes	877221
1/8 in threaded coupling fitting	Lowes	877208
1/8 in threaded male adapter nipple fitting	Lowes	877243
10/32 (M) threaded straight connector	Bimba	EB60
3/4 in 90-degree elbow CPVC fitting	Lowes	22643
3/4 in chlorinated polyvinyl chloride (CPVC) pipe	Lowes	23814
3/4 in CPVC cap	Lowes	23773
3/4 in CPVC Drip irrigation female adapter	Lowes	194629
3/4 in diameter CPVC male adapter	Lowes	23766
8.5 L airtight container with lid (11.25in x 7.75in x 6 in)	Komax	N/A	Listed as "Komax Biokips Large Bread Box | (280-oz) Large Storage Container"
Glass drain tube (1.75 in diameter x 8 in length)	KIMAX	6500
Isonic Solenoid Valves	Bimba	V2A02-AW1
Marlboro Red 100's	Marlboro	N/A
Oxygen swivel barbed connector	Global Medical Solutions	RES002
Panasonic Timer LT4H-W	Panasonic	LT4HW	Item was built-in the valve controller by Shepherd Controls & Associates
Pressure regulator	Allied Electronics and Automation	70600552	Also listed as "Norgren R07-100-RGKA"
Rubber stopper # 1 (one hole)	VWR	59581-163
Rubber stopper # 8.5 (one hole)	VWR	59581-389
Scireq inExpose system	Scireq and Emka Technologies	N/A	Commercial system used for comparison with our DIY WBIS
Straight barbed fitting (8mm opening)	VWR	10028-872
Thread Sealant tape	Lowes	1184243
Threaded port adaptor	Bimba	P1SA1
Timeter Aridyne 2000 Medical Air Compressor	MFI Medical	AHC-TE20
Timeter flowmeter	Allied Healthcare Products	15006-03YP2	Also listed as "Puritan Air Meter"
Valve Control system	Shepherd Controls and Associates	N/A	Company custom designed the valve control system for this model.
Vinyl pipes	Vitality Medical	RES3007