Why are rats used at King's?
Rats are the third most frequently used species at King’s, and the United Kingdom as a whole. Rats share 98% of their genes with humans and so many of the bodily systems that are of interest in humans can be studied in rats. The use of rats in research has decreased over the past few years due to improved technologies, e.g. smaller devices that were once only small enough for use in rats, and the popularity of genetically altered mouse strains. Genetically altered rats are becoming increasingly common in research, but are not yet an established resource at King’s.
The popularity of rats can be attributed to their genetic proximity to humans, relatively small size, short gestation period (average of 21 – 23 days) and capacity to produce large litters (6-13 pups). They are easy to train and handle and it is easier to perform more technically demanding procedures in rats than mice, e.g. vascular surgery. Indeed, some research devices have not yet been made small enough for use in mice.
Rat strains can broadly be classified or inbred or outbred. Outbred rats are the most commonly used mice at King’s, particularly Wistar rats. Inbred strains of rats are used for transplantation research as the transplantation of organs from one inbred strain to another is very useful for research into organ rejection.