Establishing a Silicosis Rat Model via Exposure of Whole-Body to Respirable Silica

Podsumowanie

This study describes a technique to establish a silicosis rat model with the inhalation of silica through the whole body in an inhalation chamber. The rats with silicosis could closely mimic the pathological process of human silicosis in an easy, cost-effective manner with good repeatability.

Streszczenie

The major cause of silicosis is the inhalation of silica in the occupational environment. Despite some anatomical and physiological differences, rodent models continue to be an essential tool for studying human silicosis. For silicosis, the classic pathological process needs to be inducible via the inhalation of freshly generated quartz particles, which means specifically inducing human occupational disease. This study described a technique to establish and effectively mimic the pathological dynamic evolution process of silicosis. Further, the technique had good repeatability with no surgery involved. The inhalation exposure system was fabricated, validated, and used for toxicology studies on respirable particle inhalation. The critical components were as follows: (1) bulk dry SiO₂ powder generator adjusted with an air-flow controller; (2) 0.3 m³ whole-body inhalation exposure chamber accommodating up to 3 adult rats; (3) a monitoring and control system for regulating oxygen concentration, temperature, humidity, and pressure in real-time; and (4) a barrier and waste disposal system for protecting laboratory technicians and the environment. In summary, the present protocol reports the inhalation via the whole body, and the inhalation chamber created a reliable, reasonable, and repeatable rat silicotic model with low mortality, less injury, and more protection.

Wprowadzenie

Silicosis, which is caused by the inhalation of silica, is the most serious occupational disease in China, accounting for more than 80% of the total number of occupational disease reports every year¹. The etiology of silicosis is clear, and it can be prevented and controlled, but no effective treatment method is available². Many drugs have been proven to be effective in basic studies, but they have imprecise clinical effects^3,4. Therefore, the pathological and physiological mechanisms of silicosis still need to be explored.

Protokół

All animal experiments were conducted according to the United States National Institutes of Health Guide for the Care and Use of Laboratory Animals and approved by the Committee on the Ethics of North China University of Science and Technology (protocol code LX2019033 and 2019-3-3 of approval). Male Wistar rats, 3 weeks of age, were used for the present study. All rats were kept in static cages with wood shavings. The animals were maintained in a 12 h/12 h light/dark cycle, and were provided with food and water ad libitum. Follow-up experiments were conducted after 1 week of adaptive feeding.

1. Animal preparation

Wyniki

Using the proposed method, some potential mechanisms and the pathogenesis of silicosis were explored in rats. The schematic of the inhalation chamber is shown in Figure 1. The chamber consisted of an air-delivered silica generator, a whole-body chamber, and a waste disposal system, as previously described¹⁷. The pulmonary functions, levels of inflammatory factors in the serum and lung, collagen deposition, and myofibroblast differentiation were reported in the previou.......

Dyskusje

As the leading cause of silicosis, silica plays a decisive role in molding. The silica particles inhaled by patients with pneumoconiosis are fresh, free silica particles produced by mechanical cutting. Silica can generate reactive oxygen species either directly on freshly cleaved particle surfaces or indirectly through its effect on the macrophages²⁵. Therefore, the grinding of silica particles is of high importance. In the proposed protocol, silica was ground with agate mortar for more than 90 mi.......

Materiały

Name	Company	Catalog Number	Comments
Air detector (compressive atmospheric sampler)	Qingdao Xuyu Environmental Protection Technology Co. LTD
Anatomical table			No specific brand is recommended.
Antibody of CD68	Abcam	ab201340
DAB	ZSGB-BIO	ZLI-9018
Electric heating air-blowing drier	Shanghai Yiheng Scientific Instrument Co., LTD
Electronic balance	OHRUS
Embedding machine	leica
Exhaust gas discharge device	HOPE Industry and Trade Co. Ltd.
Generator systems	HOPE Industry and Trade Co. Ltd.
Gloves (thin laboratory gloves)	The secco medical
Hematoxylin and eosin	BaSO Diagnostics Inc.	BA4025
HOPE MED 8050 exposure control apparatus	HOPE Industry and Trade Co. Ltd.
Inhalation chamber	HOPE Industry and Trade Co. Ltd.
Injection syringe			No specific brand is recommended.
Light microscope	olympus
Object slide	shitai
PV-6000 (HRP-conjugated goat anti-mouse IgG polymer)	Beijing Zhongshan Jinqiao Biotechnology Co. Ltd	s5631
Silicon dioxide	Sigma-Aldrich
Slicing machine	leica	RM2255
Waste gas treatment device	HOPE Industry and Trade Co. Ltd.
Wet box	Cooperative plastic Products Factory
Xylol	Tianjin Yongda Chemical Reagent Co., LTD