Methods for Establishment and Maintenance of Germ-Free Rat Models.

Lingling Qv,Zhenggang Yang,Sunbing Mao,Mingfei Yao,Jia Zhang,Lanjuan Li,Yongjun Li

doi:10.3389/fmicb.2020.01148

Lingling Qv, Zhenggang Yang + Show 5 more

Open Access

https://doi.org/10.3389/fmicb.2020.01148

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Abstract

Numerous studies have demonstrated that the gut microbiota plays a vital role in human health and disease development. Although the number of studies on host–microbiota interactions have increased in recent years, the underlying pathogenesis of dysbiosis-related diseases are still largely unknown. Germ-free (GF) rodent models, with the animals housed in sterile isolators and completely free of microbiota, are useful tools to advance our understanding of host–microbiota relationship in vivo. Although protocols concerning the establishment and maintenance of GF mouse models have previously been reported, the establishment, maintenance and monitoring of GF rodents are labor-intensive, tedious and take experience and skills. The aim of our study was to establish a GF rat model for the following microbiota-related researches and provide an easy-to-use protocol for the establishment and maintenance of GF rat model in detail, including steps to set up the isolator, sterilize the flexible isolator bubble, import food, water and other supplies, and methods to acquire newborn GF rats, hand rearing of suckling GF rats and reproduction of GF offspring. During the hand feeding period, the body weight of suckling GF rats was weighed once a day to ascertain the amount of artificial milk was given. Based on our results, the body weight of suckling GF rats decreased 1 week after birth and then began to increase. Methods for verifying the quality of the model like assessing the sterile status of the rat colony are also described. Moreover, possible difficulties and challenges, especially during gavage, and suggestions to avoid contamination will be discussed. The protocol presented will facilitate the establishment of GF rat models and downstream microbiota-related researches.

Highlights

The human gastrointestinal (GI) tract contains trillions of microbes, including bacteria, viruses, archaea, fungi, parasites and protozoa (Qin et al, 2010; Carding et al, 2017)
Germ-Free Rat Model tract was sterile in utero and that the first colonization and initiation of gut microbiota began during the delivery process (Salazar et al, 2014)
The brain heart infusion (BHI), fluid thioglycollate (FT), and tryptic soy broth (TSB) broths supplemented with fecal samples showed no visible growth of bacteria after 7 days of incubation, and the blood agar plates showed no growth of colonies after 2 days of cultivation

Summary

Introduction

The human gastrointestinal (GI) tract contains trillions of microbes, including bacteria, viruses, archaea, fungi, parasites and protozoa (Qin et al, 2010; Carding et al, 2017). Accumulating evidence suggests that the gut microbiota play a critical role in promoting human health through various means including production of vitamins, absorption of nutrients, pathogen displacement and development of the immune system (O’Hara and Shanahan, 2006). Germ-Free Rat Model tract was sterile in utero and that the first colonization and initiation of gut microbiota began during the delivery process (Salazar et al, 2014). The direct role of the gut microbiota in disease development and the underlying mechanisms relating dysbiosis to deteriorating health have not yet been fully elucidated and further researches on the topic are urgently needed

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