Pain and stress relief tests use larval zebrafish
The primary goal of the FISH (Fish indicators of stress and health (FISH): Validating the use of embryos and yolk sac larval zebrafish as a model for the study of nociception and veterinary drug testing) project was to reduce the number of adult zebrafish used in scientific procedures. Researchers at the University of Liverpool tested the larvae as a valid replacement for the adults in tests on potential analgesics. FISH scientists developed new scoring software that can monitor the movements of 25 larval zebrafish in the same well simultaneously. After noxious stimuli, both larvae and adults had reduced activity. Responses to chemical and thermal stimuli were recorded successfully. Subsequent testing with painkillers at different doses including aspirin, lidocaine, morphine and flunixin showed that responses were reduced on application of the pharmaceuticals. Investigation of genomic response to nociception in the larvae showed that there were 141 genes involved in common with the adults. Moreover, many of the transcription products are involved in mammalian pain. Using two photon fluorescence microscopy linked to calcium signalling, they identified several brain areas – the fore-, mid- and hindbrain – that are responsive to noxious stimulation. Research results from the FISH initiative have shown that zebrafish larvae are a valid alternative to adults in the area of pain research and pain-relieving drugs. This new knowledge platform can also be used to reduce stress in aquaculture as well as ornamental fish in the pet trade. The researchers anticipate there will be publications in three peer-review journals covering their work.
Keywords
Pain, larval zebrafish, analgesic, FISH, scoring software
