The use of restraint devices in certain laboratory experiments is vital to the successful collection of data and completion of the experiment. Therefore, the right device must be chosen to aid in this success. Due to this, a variety of restraint devices exist from which the researcher can choose, and these varieties can be composed of different materials and used for multiple purposes. According to Machholz, et al., one type of restraint device is the Decapicone, which is “a flexible, cone-shaped piece of thin plastic with a hole in one end. The hole is small enough so the mouse or rat can get its nose out of the hole, but not the rest of the body” (Machholz et al.). They further explain how the material of which the Decapicone is composed is thin enough for syringe needles to penetrate in order to inject certain fluids into the rat, but is not breathable enough to accommodate rats for longer than is necessary to successfully perform the procedure (Machholz et al.).
As described by Stewart and Schroeder, other restraint devices can be rigid and composed of nonporous substances or more flexible. For example, one such device is cylindrical with slots on one of its sides allowing for the easy placement of the rat within this device. The rat is pulled by its back end through this restraint, and the restraint is then closed on the snout side of the rat, still allowing for comfortable breathing. Another device has a flattened bottom with apertures at various locations that allow for certain procedures to be easily carried out, while still enclosing the rat to prevent escape. Another similar device is a tube restraint with holes in the cap at one of its ends for breathing and a slit in one of its sides for any relevant procedures to occur. A more flexible type of restraint device is the plastic cone. For this cone to work, its tip must be cut to the correct diameter to produce an opening that will allow the rat to breathe and its other end must be twisted around the rat’s tail and tied so that the rat cannot escape. This type of restraint also allows for injections to enter the rat’s body by going through the plastic material (Stewart and Schroeder).
Although restraint devices composed of plastic appear to be quite prevalent, they may not be the best method to use. According to Kemp, “Tube restrainers are only ideal for immobilization over short periods as heat dissipation can be a problem” (Kemp 41). Thus, Kemp describes an alternative composed of fabric. This alternative uses a piece of fabric that is formed into a tent shape over a board of certain thickness, with one end of the fabric higher up off the board than the other. This fabric is then bolted to the board, forming an effective restraint device that is more breathable than one made of plastic. Also, researchers could use restraining harnesses that can adjust to permit appropriate comfort of the rat and can attach to certain structures to hinder escape of the rat (Kemp 40-41).
One restraint methods is the one handed rat restraint. This restraint only involves using your non dominant hand to hold the rat near the base of the skull and using your dominant hand to perform the experiment. There are also other hand restraint methods. Though this technique is useful short term, if a rodent needs to be immobilized for a longer period of time a restraint is required.
When designing restraint devices, the rat’s stress level should be taken into account. If a rat needs to be repeatedly put into the restraint, it should not cause undue stress as it is detrimental to the rat. The easiest method to restrain the rat is to wrap it in muslin (Kemp). Wrapping the rat allows for access to the tail while still keeping the rat comfortable. Though this restraint is simple and easy to use, it sometimes requires the use of one or more people to wrap the rat. We would like our restraint to be usable by one person.
Another restraint method is the plastic tube. The rat is carefully placed in the tube and the tail extends out of a hole to make it accessible for experiments. This method is typically easy to use and can be done with one person. However, the rat is fully contained in a tube making it difficult to access the face and body for other tests. Also, this restraint is only meant for short experiments as the rats can lose heat and it is not comfortable for the rats (Kemp). A final restraint device is the rat tent. This method has been shown to cause less stress than the tube and rats can be in the restraint for longer periods of time (Kemp). This restraint may be something we should look further into as the whole rat’s body is accessible and it can be used by one person. Some commercial rat restraints are the mouse rat tail cuff blood pressure system, manual indirect rat tail blood pressure system, and the Harvard Snuggle.