A Pleural Effusion Model in Rats by Intratracheal Instillation of Polyacrylate/Nanosilica

Summary

Here, we present a protocol to construct a pleural effusion model in rats by intratracheal instillation of polyacrylate/nanosilica.

Abstract

Pleural effusion is a prevalent clinical finding of many pulmonary diseases. Having a useful animal pleural effusion model is very important to study these pulmonary diseases. Previous pleural effusion models paid more attention to biological factors rather than nanoparticles in the environment. Here, we introduce a model to make pleural effusion in rats by intratracheal instillation of polyacrylate/nanosilica, and a method of nanoparticle isolation in the pleural effusion. By intratracheal instillation of polyacrylate/nanosilica with concentrations of 3.125, 6.25 and 12.5 mg/kg∙mL, the pleural effusion in rats presented on day 3, peaked at days 7-10 in 6.25 and 12.5 mg/kg∙mL groups, then slowly decreased and disappeared on day 14. When the concentration of polyacrylate/nanosilica increased, the pleural effusion is produced more and faster. This pleural fluid was detected by ultrasound examination or CT chest scanning and confirmed by dissection of rats. Silica nanoparticles were observed in the rats' pleural effusion by transmission electron microscope. These results showed that the exposure to polyacrylate/nanosilica leads to the induction of pleural effusion, which was consistent with our previous report in humans. Additionally, this model is beneficial for the further study of nanotoxicology and the pleural effusion diseases.

Introduction

Pleural effusion is a very common clinical manifestation of pulmonary diseases with a variety of causes. Having a useful animal pleural effusion model is very important to study these pulmonary diseases, the roles of the two pleural membrane layers, the mechanisms of pleural effusion, and its treatment. However, some reported pleural effusion models mainly focus on the malignant pleural effusion or biological factors rather than the nanoparticles in the environment^1,2. Here, we introduce a new model of pleural effusion that is simple, safe and effective.

With the development of nano....

Protocol

The study followed guidelines of Capital Medical University (Beijing, P.R China) for the care and use of experimental animals. All procedures were approved by the Animal Ethical Committee of Capital Medical University in China.

1. Experimental preparations

NOTE: Acclimate the female specific pathogen-free Wistar rats (weight: 200 ± 10 g) to the experimental environments for a week before administration (Environmental conditions: light/dark:12h/12h, temperature 22 ± 2 °C, humidity 50 ± 10 %).

1. Use a fresh 10 mL of PA/NPSi suspensions (nanosilica Ø:20 ± 5 nm by in situ emuls....

Results

Using a thoracic ultrasound, we found no pleural effusions on day 1 in all groups. However, on day 3, the pleural effusion appeared in the 6.25 and 12.5 mg/kg∙mL groups. The effusion was mainly in the right costal phrenic angle, while the pericardial effusion only presented in 12.5 mg/kg∙mL group. Furthermore, on day 7, both pleural effusion (Video 1) and pericardial effusion (Video 2) were detected in 6.25 mg/kg∙mL group (

Discussion

Sonography is the most convenient tool for determining pulmonary diseases, due to its excellent sensitivity to the free fluid in the pleural cavity¹¹. That is because sonography can immediately detect the contrast in acoustic impedance of air and fluids in the lung¹². Besides, sonography is more flexible in a small animal's model than CT. Nevertheless, the air in the lung reflected the sound wave and impeded from observing the intrapulmonary changes after nanoparticles .......

Materials

Name	Company	Catalog Number	Comments
Acuson S2000 Color Doppler ultrasound system	Siemens Medical Solutions, Mountain View ,CA
Polyacrylate/nanosilica	Fudan University,Shanghai, China		made by order with nanosilica(20±5)nm
10% chloral hydrate	Beijing Chemical Works	302-17-0
Transmission electron microscope	JEM-1400Plus，JEOL Ltd., Japan.
Light speed 16 spiral computed tomography	GE Healthcare, US
Specific pathogen-free Wistar	Animal Center of Lianhelihua (Beijing, China)		Wistar rats