As someone who has worked with lab animals, will be going to vet school to major in lab animal medicine, and has rats let me clear the air a bit. Lab animal research is not what is depicted on TV or the pictures that PETA shows you. There are very strict laws and guidelines surrounding the use of animals for research. The Institutional Animal Care and Use Committee or IACUC MUST approve all experiments, methods, and facilities before testing can begin. If IACUC does not approve an experiment it must be altered until it is deemed acceptable if it is going to be done at all.
The do not approve: unnecessarily painful procedures, experiments that don't show reason to be repeated, or facilities that do not provide adequate veterinary care. Did you know that animals are only allowed to undergo ONE surgery or procedure that requires an extended recovery time. Did you know they stop the experiment if the animal is showing pain or administer medications? Did you know that if the testing facility is not checking for the potential lethality of a drug they will halt the experiment if the animals are showing signs of distress due to the medication? Do you think animals like cats and dogs come from shelters? No, the don't. All lab animals are specifically bred to be used in a laboratory facility, they are not taking pets from shelters. The facility where I worked even adopted out animals after they were done with experiments instead of euthanizing them.
People who test on animals aren't monsters. Is it unpleasant? Yes. Is it a fact of life? Yes. Those animals save the lives of countless humans and animals.