TABLE 1.

Advantages and disadvantages of different species as preclinical models of trauma

	Advantages	Disadvantages	Immune cell composition (%)	Common uses in trauma research
Mice	Inexpensive Easy to handle Huge variety of genetic knock‐in/knockouts available Large cohorts Rapid breeding cycle Broad availability of biological reagents	Small TBV (relative to large animals) Difficult to manipulate Genetically the most different from humans Short life span	Neutrophils: 10%–25% Lymphocytes: 50%–90% Monocytes: 1%–4%	Drug metabolism and screening Mechanistic studies (i.e. transgenic mice) Traumatic brain injury Wound healing
Rat	Inexpensive Easy to handle Some genetic knock‐in/knockouts available Large cohorts Broad variability of biological reagents	Small TBV (relative to large animals) Short life span	Neutrophils: 4%–20% Lymphocytes: >70% Monocytes: 1%–4%	Haemorrhagic shock Wound healing Toxicology Mechanistic studies
Rabbit	Large TBV (relative to rodents) Inexpensive (relative to large animal models) Bone physiology similar to humans Superior humoral immune responses Comparable neutrophil responses to humans Long life span (relative to rodents)	Challenging to find biological reagents Genetically more similar to humans that rodents	Neutrophils: >30% Lymphocytes: 60‐70% Monocytes: 1%–5%	Fracture and traumatic bone injury Drug metabolism Haemorrhagic shock Tissue injury
Pig	Large TBV Some cross‐reactivity with human reagents Comparable lymphoid structures to humans Long life span (relative to rodents)	Complex medical equipment required Challenging to produce large cohorts Challenging to find biological reagents	Neutrophils: 20%–45% Lymphocytes: 30%–70% Monocytes: 1%–10%	Haemorrhagic shock Fluid resuscitation Tissue injury Coagulopathy
Sheep	Large TBV Bone physiology similar to humans’ long life span (relative to rodents)	Complex medical equipment required Challenging to produce large cohorts Challenging to find biological reagents	Neutrophils: 25%–30% Lymphocytes: 60%–70% Monocytes: 1%–6%	Coagulopathy Fracture and traumatic bone injury
Goat	Large TBV Bone physiology similar to humans Long life span (relative to rodents)	Complex medical equipment required Challenging to produce large cohorts Challenging to find biological reagents	Neutrophils: 25%–30% Lymphocytes: 60%–70% Monocytes: 1%–10%	Fracture and traumatic bone injury
Non‐human primates	Large TBV Immune responses Broad cross‐reactivity with human reagents Long life span (relative to rodents)	Complex medical equipment required Less ethically accepted Challenging to produce large cohorts	Neutrophils: 40%–60% Lymphocytes: 30%–50% Monocytes: 1%–4%	Haemorrhagic shock Fluid resuscitation Coagulopathy