Animal Research Demonstrates Hair Cell Regeneration In mammals, such as humans and mice, cochlear hair cells appear to lack the capability for regeneration (Rubel et al., 2005), whereas non-mammalian lower vertebrates often show striking regenerative abilities in their sensory epithelia of fish, amphibians, reptiles and birds. Here, we discuss the mechanisms underlying regeneration of hair cells in different species and their possible bearing on lessons learned from regenerative hair-cell treatments implemented in mammals.
Hair Cell Regeneration Mechanisms
Lower Vertebrates:
FishFishes such as the zebrafish can successfully regenerate hair cells following injury. Whether supporting cells proliferate or transdifferentiate into hair cells, studies have demonstrated rapidhair cell regeneration and recovery of auditory function. For example, upon gentamicin exposure (a known ototoxic drug), zebrafish are able to regenerate all of their lateral-line hair cells in 72 hours15.
Amphibians and Reptiles: These species have similar processes where supporting cells help regrow the hair cell layer through division or transformation of soccer into hairs Microsoft Word – _Paper_Defense.doc
Birds:
Unlike mammals, birds are capable of regenerating auditory hair cells throughout their lives. According to a recent study, birds are able to regain their hearing after suffering damage through the replacement of hair cells that relay neural signals back and forth along neurological pathways in the brain. This process is mediated via mitosis and transdifferentiation of supporting cells .
Lessons for mammalian studies
While adult mammals have a low-hearing regeneration, studying these mechanisms in lower vertebrates has might lead to therapies for hearing attenuation. By stimulating similar regenerative pathways in mammals, researchers hope to develop therapies war- ranted for clinical use (Fig. 2).hair cell regeneration (ad) Methods range from controlling gene expression with hair cells, development to defining the function of supporting cells during regeneration126.
Conclusion
Investigating hair cell regeneration in different species helps to improve our understanding of auditory biology, and will aid the development of novel strategies for therapy to restore hearing capacity in humans. The challenge is to use the regenerative capabilities seen in lower vertebrates and reproduce those influences within mammalian systems.
