Biological Data, Rat Handling Procedure, and IACUC Standards Informational Report

Table of Contents

1. Standard Rodent Handling Procedure
2. Biological Data Concerning Typical Laboratory Rat Species
3. Recognition of Distress in Rats
4. Assessment of Aggression in Rats
5. References

Standard Rodent Handling Procedure

Various criteria and rules exist that should be followed correctly during experiments in order to mitigate problems related to the handling of rodents, such as rats. According to the “Basic Rat Handling and Technique Workshop” article from UNC-Chapel Hill, it is best for the rats if they are handled gently and it would be beneficial to help the rat acclimate itself to handling procedures and to the usage of restraints for experimentation. This helps to decrease any anxiety that rat may experience. In addition, the researcher should determine which handling technique is appropriate for the rat, the experiment, and himself or herself (“Basic Rat Handling and Technique Workshop”). Furthermore, the article entitled “2 Animal Care and Use Program” describes certain restrictions on the use of restraints. It states: “Restraint devices should be suitable in size, design, and operation to minimize discomfort, pain, distress, and the potential for injury to the animal and the research staff” (“2 Animal Care and Use Program”). This statement illustrates a need for humane devices that can successfully aid in the execution of an experiment and provides information that is pertinent to our design project and that needs to be considered during our design process. The “2 Animal Care and Use Program” article also indicates how the rodent or animal that is being used in the experiment should be constantly monitored so as to ensure the health and safety of the specimen during the procedure. Monitoring should help determine whether or not the specimen has endured any injuries or sores from the use of the restraint (“2 Animal Care and Use Program”). This is corroborated by the “Animal Handling and Restraint” article which asserts that restraint devices should not cause discomfort to the rodent being used in the experiment, but should be developed and used in such a way so as to diminish the degree of harm that could be inflicted upon the rodent. This article also declares that the use of a restraint on a rat for an extended period of time must be sanctioned by IACUC before the rat can undergo such a process (“Animal Handling and Restraint”). Therefore, researchers must greatly consider how to handle rodents and use restraints most appropriately during their experiments.

Biological Data Concerning Typical Laboratory Rat Species

Understanding rat physiology is key to developing a product that is functional for the research community. Below is a table showing average data for lab rat physiology. Data of note within this table includes body temperature, weight of males and females at adulthood and birth, breathing rate, and oxygen consumption. This data will be useful when moving forward to determine what type of restraint we will design and how we will incorporate temperature, respiration, and pressure telemetry sensors into this design.

https://www.research.uky.edu/dlar/documents/Commonly_Used_Strains_of_Rats.pdf

Recognition of Distress in Rats

Animals exhibit a variety of behavioral changes as part of the normal aging process. Males and females differ in the baseline values of many stress markers. Inbred murine strains differ in almost every behavioral, sensory, motor, and physiological trait studied and each inbred strain may respond to stress differently. Similar behavioral differences in response to stress have been observed in primates. Genetically engineered phenotypes need to be considered when assessing stress and distress in transgenic and knockout animals. The maternal environment and rearing experiences of the offspring affect their future responses to stress and distress. Special physiological states, such as impending parturition, are defined by state-specific behaviors. Housing conditions may also modify species-specific behavioral patterns.

Clinical examination to establish the presence of distress should focus on, but not be limited to, the following:

● signs of abnormal respiration

○ shallow, labored, or rapid

● assessment of grooming and hair coat

○ piloerected or greasy, possibly reflecting reduced grooming

● examination of the eyes

○ runny, glassy, or unfocused

● examination of motor postures

○ hunching or cowering in the corner of the cage, lying on one’s side, lack of movement with loss of muscle tone

● absence of alertness or quiescence

○ inattention to ongoing stimuli

● changes in body weight

● the ability or failure to produce urine or feces; unusual features of urine or feces

○ urine: volume, smell, and color

○ feces: quantity, consistency, and color

● the presence of vomit

● the status of the animal’s appetite and water intake

intense or frequent vocalizations

Assessment of Aggression in Rats

Aggression is defined as an adaptation for situations that contain physical conflict or species conflict (Scott, 1996). Most of the research that has been conducted on rodents has investigated the significance of aggression and how it aids in the survival and reproduction of the rodent, as aggressive behavior can lead to increase in food, water, and shelter acquisition.

There are two types of aggression rodents display: offensive and defensive. Offensive aggression is an attack on another animal and includes “sideways threats, tail chasing, defensive upright procedures, and attack bites” (Miczeck and O’ Donnell, 1978). However in our experiment, we are more concerned with defensive behaviors in which the rodent shows aggression to protect itself from physical harm. Male rodents tend to show the following defensive behaviors “escape, freezing, defensive postures, and threats” (Blanchard and Blanchard, 2003) and it has been shown that laboratory rodents, aggressiveness is limited mostly to males (Takahashi and Miczeck, 2013). Females tend to show aggression port-partum to protect their offspring from males.

Many experiments have been conducted to determine the aggressiveness of rodents. One such example is isolating the rodent and analyzing their reaction when placed with other rodents; males typically have a full aggression response. Another experiment is the resident-intruder experiment in which a male is placed with a female to mimic their natural environment and an intruder was introduced into the setting. The amount of aggression displayed by the original rat depended on the intruder and their age, hormonal status, and the original rat’s experience. For example, if the intruder rat had won a previous fight, the resident rat would not attack it. The purpose of female aggression is mostly to protect offspring and a lactating female rat will display offensive aggression towards a variety of intruders. The most severe response occurs during the first part of the lactation period (Olivier and Young, 2002).

References

• “Animal Handling and Restraint.” Course Materials. Animal Research Facility Rajiv Gandhi Centre for Biotechnology, n.d. http://210.212.254.115:198/arf/p1.php. Accessed 12 Sept. 2017.
• “Basic Rat Handling and Technique Workshop” [PDF document]. Research.unc.edu. UNC Chapel Hill, Feb. 2017. https://research.unc.edu/files/2017/03/Rat-Handling-and-Techniques.pdf. Accessed 11 Sept. 2017.
• Blanchard DC, Blanchard RJ. What can animal aggression research tell us about human aggression? Horm Behav. 2003;44:171–177.
• Dale J Langford, Andrea L Bailey, Mona Lisa Chanda, Sarah E Clarke, Tanya E Drummond et al. Coding of facial expressions of pain in the laboratory mouse. Nature Methods 7, 447-449 (May 9, 2010)
• Miczek KA, O’Donnell JM. Intruder-evoked aggression in isolated and nonisolated mice: effects of psychomotor stimulants and L-dopa. Psychopharmacology. 1978;57:47–55
• National Research Council (US) Committee on Recognition and Alleviation of Distress in Laboratory Animals. Recognition and Alleviation of Distress in Laboratory Animals. Washington (DC): National Academies Press (US); 2008. 3, Recognition and Assessment of Stress and Distress. Available from: https://www.ncbi.nlm.nih.gov/books/NBK4033/
• Oliver B, Larry Y. Animal Models of Aggression. Neuropsychopharmacology: The fifth generation of progress. 2002
• Scott JP. Agonistic behavior of mice and rats: a review. Am Zool. 1966;6:683–701.
• Takahasi A, Miczek KA. Neurogenetic of Aggressive Behavior-Studies in Rodents. Behavioral Neuroscience. 2015;17:3-44
• “2 Animal Care and Use Program.” National Research Council. 2011. Guide for the Care and Use of Laboratory Animals: Eighth Edition. Washington, DC: The National Academies Press. doi: 10.17226/12910. https://www.nap.edu/read/12910/chapter/3#13. Accessed 12 Sept. 2017.