Animal Model Rats Related Ages with Human’s in Biomedical Research

The laboratory rat is an inevitable part of today's biomedical research. They arerecognized as the preeminent model in numerous fields, including neurobehavioralstudies, cancer and toxicology. It is difficult to evaluate the number of animalsemployed in scientific experiments every year. An estimation suggests some dozensof millions per year, being 15 million in the United States, 11 million in Europe, fivemillion in Japan, two million in Canada and less than one million in Australia.Almost 80% of the experimental animals are rodents that include mice, rats, guineapigs and others (10% are fish, amphibians, reptiles and birds). A third group includesrabbits, goats, bulls and in smaller amounts, dogs, cats and some species ofprimatess.

Magnetic resonance imaging for early pregnancy diagnosis in the laboratory rat

Pregnancy diagnosis and embryo counting are important end points in reproductive, developmental biology and toxicology studies. The purpose of the present study was to assess the feasibility and efficacy of magnetic resonance imaging (MRI) for early pregnancy diagnosis and embryo counting in the laboratory rat. Female Wistar rats were subjected to whole-body MRI scanning using a 1.5T MRI scanner, employing a isotropic T2-weighted 3D short-tau inversion recovery sequence from day 8 to day 12 post coitum (pc) or without prior mating, under general anaesthesia for pregnancy diagnosis and embryo counting. MRI examination was followed by laparotomy and visual inspection of the uterus to verify MRI findings. By day 8 pc, uterine bulges, characteristic of pregnancy, were depicted as oval-shaped structures of high intensity signal. By day 10 pc, embryonic vesicles were detected at the medial side of the uterine bulges. Pregnancy was diagnosed with 0% false-negative diagnosis and 100% accuracy by day 11 pc, while embryos were counted with 100% accuracy by day 12 pc. In conclusion, MRI proved to be a feasible and reliable non-invasive imaging method of early pregnancy diagnosis and embryo counting in the laboratory rat.

PCR SURVEILLANCE OF FOUR PROTOTYPIC RAT PARVOVIRUSES IN LABORATORY RAT COLONIES IN TAIWAN

Prototypic rat parvoviruses are among the most common infectious agents in laboratory rats worldwide. It is important to determine the infectious condition of rat parvoviruses in research colonies in Taiwan. In this study, virus species-specific PCR assays were applied to screen Kilham rat virus (KRV), Toolan’s H-1 virus (H-1 virus), rat parvovirus (RPV) and rat minute virus (RMV) in 203 rats from five different research colonies in Taiwan. In this survey, the infection rate of rat parvoviruses was 19.2% (39/203), including KRV (12.3%; 25/203), RMV (8.9%; 18/203) and RPV (1.0%; 2/203). Dual infection of KRV and RMV were detected in 3.0% (6/203) of samples. No rats were positive for H-1 virus. The infectious rates of KRV and RMV detected in this study are much higher than those reported in USA and in Europe. Rat parvovirus PCR assays reported in this paper could be a useful tool for routine rat health monitoring program applied in laboratory rat facilities. [Chang YH, Liao YC, Wang KW, Hsieh SC, Wang MH, Fang BH, Chang CY, Chueh LL, Wan CH, PCR Surveillance of four prototypic rat parvoviruses in laboratory rat colonies in Taiwan, Taiwan Vet J 46(1): 1–7, 2020]

Bring Back the Rat!

As 2020 is “The Year of the Rat” in the Chinese astrological calendar, it seems an appropriate time to consider whether we should bring back the laboratory rat to front-and-center in research on the basic biology of mammalian aging. Beginning in the 1970s, aging research with rats became common, peaking in 1992 but then declined dramatically by 2018 as the mouse became preeminent. The purpose of this review is to highlight some of the historical contributions as well as current advantages of the rat as a mammalian model of human aging, because we suspect at least a generation of researchers is no longer aware of this history or these advantages. Herein, we compare and contrast the mouse and rat in the context of several biological domains relevant to their use as appropriate models of aging: phylogeny/domestication, longevity interventions, pathology/physiology, and behavior/cognition. It is not the goal of this review to give a complete characterization of the differences between mice and rats, but to provide important examples of why using rats as well as mice is important to advance our understanding of the biology of aging.

The Norway rat, from an obnoxious pest to a laboratory pet

The laboratory rat was the first mammal domesticated for research purposes. It is descended from wild Norway rats, Rattus norvegicus, which despite their name likely originated in Asia. Exceptionally adaptable, these rodents now inhabit almost all environments on Earth, especially near human settlements where they are often seen as pests. The laboratory rat thrives in captivity, and its domestication has produced many inbred and outbred lines that are used for different purposes, including medical trials and behavioral studies. Differences between wild Norway rats and their laboratory counterparts were first noted in the early 20th century and led some researchers to later question its value as a model organism. While these views are probably unjustified, the advanced domestication of the laboratory rat does suggest that resuming studies of wild rats could benefit the wider research community.