WHY USE ANIMALS?  Human beings use animals for a wide variety of purposes  260 million people in the US have pets  More than 5 billion animals are consumed each year as food  An estimated 17 million animals are use for Biomedical Research each year

 Animals are used to learn more about biological systems and the illnesses that afflict human beings and other animals  Animals serve as surrogates for humans  Some animals have biological similarities to humans that make them good models for specific diseases  Research has unlocked the secret of genetics, shed light on the workings of the brain, made it possible to understand new diseases like AIDS  Animals that we keep as pets live longer, healthier lives because of research

 Animals are used in Biomedical Research because:  It is not ethical to test substances or drugs with unknown and potentially adverse side effects on humans.  Controlled experiments introduce only one variable at a time.  Animal populations are easily controlled in a laboratory setting  Human environments and genetic backgrounds vary widely, making it difficult to control variables  There is no substitute for the living systems necessary to study interaction among cells, tissues and organs.

 Shorter life spans of animals enable scientists to study effects over shorter periods of time.  Rats have a life span of 2 to 3 years and reproduce rapidly, allowing scientists to study several generations in a shorter time period than in humans.

PAST TRAGEDIES  Early 1930’s – untested eyelash dye called “Lash Lure” introduced to the market in the US. Contained a substance called p-phenylenediamine which sensitized ocular structures, leading to corneal ulceration and loss of vision. Also caused one death.  1937 – antibacterial medicine sold in the US as a liquid dissolved in diethylene glycol (antifreeze) caused 107 deaths  1980’s – teflon-coated disk implanted into the jaws of thousands of TMJ patients had to be removed. The device broke into microscopic fragments, causing a biochemical reaction that eroded the jaw bone.

 Before 1976, medical devices did not require approval from the FDA before being marketed.  Today, FDA approval is required prior to being introduced  Medical devices must undergo extensive laboratory tests, animal experiments and human clinical trials

MOST COMMONLY USED ANIMAL MODELS  Cats – used because of their well developed hearing systems and brain mechanisms for hearing. Can be trained to respond to many behavioral cues given through auditory stimuli. Also have naturally occurring hearing defects and are susceptible to environmentally induced defects, as are humans

 Primates – Used to study the immune system. Have immunological similarities to humans and are susceptible to similar diseases. They often react to the same infectious agents as humans.  Dogs – Cardiovascular system. Structured similarly to humans and suffer from many inherited defects that affect humans. Endocrine system also similar in that dogs can have diabetes as well as diabetic problems such as glaucoma.

 Mice – Aging. Mice age 30 times more rapidly than humans, with several body systems declining with age in the same manner as humans. Genetic composition and environmental conditions can be precisely and easily duplicated and controlled.  Rats – Show major, spontaneously developing and age-related damage in most major systems of the body that commonly are seen in humans.

 Squid – Nervous system. Movement of nutrients through nerve cells are studied. They have the largest axons and are used to study ALS in humans.  Sea urchins – Reproduction. Chromosomes and heredity, cell growth and division, fertilization and embryonic developments are studied. They have large, easily obtained gametes. Used to study birth defects due to chromosomal activity.

 Armadillo – Reproduction & developmental biology. Can give birth up to three years after fertilization. Experience delayed implantation of the fertilized egg and give birth to identical quadruplets. Their low body temperature allows leprosy to grow. Used to study twins, menopause, infertility and leprosy in humans.

 Ferrets – Immune system. Both ferrets and humans are affected by closely related bacteria. Used to study gastritis and stomach ulcers.  Seals – Respiratory and nervous systems. Young seals exhibit similar characteristics to humans when they hold their breath for long dives or when sleeping under water. Used to study SIDS in infants.