Ji Ho Ryu; JonuPradhan; Myeung Ju Kim & Dhiraj Maskey
The term “circling mouse” refers to an animal model of deafness, in which the mouse exhibits circling, head tossing, and hyperactivity, with pathological features including degenerated spiral ganglion cells in the cochlea, and the loss of the organ of Corti. The cochlear nuclear (CN) complex, a part of the auditory brain circuit, is essential to process both ascending and descending auditory information. Considering calcium’s (Ca2+) importance in homeostasis of numerous biological processes, hearing loss by cochlear damage, either by ablation or genetic defect, could cause changes in the Ca2+ concentration that might trigger functional and structural alterations in the auditory circuit. However, little is known about the correlation of the central nervous system (CNS) pathology in circling mice, especially of the auditory pathway circuit and Ca2+ changes. This present study investigates the distribution of Ca2+- binding proteins (CaBPs), calbindin D-28k (CB), parvalbumin (PV), and calretinin (CR) by using a free floating immunohistochemical method inthe CN of the wild-type mouse (+/+), the heterozygous mouse (+/cir), and the homozygous (cir/cir) mouse. CaBPs are well known to be an important factor that regulates Ca2+ concentrations. Compared with the dorsal and ventral cochlear nuclei of +/+ and +/ cirmice, prominent decreases of CaBPs’ immunoreactivity (IR) in cir/cirmice were observed in the somas, as well as in the neuropil. The present study reportson the overall distribution and changes in the immunoreactivity of CaBPs in the CN of cir/cirmice because ofa hearing defect. This data might be helpful to morphologically elucidate CNS disorders and their relation to CaBPs immunoreactivity related to hearing defects.
KEY WORDS: Calretinin; Calbindin D28-k; Cochlear Nuclear Complex; Circling mouse; Parvalbumin.
RYU, J. H.; PRADHAN, J.; KIM, M. J. & MASKEY, D. Immunohistochemical distributionof calcium binding proteins in the cochlear nuclear complex of circling mice. Int. J. Morphol., 39(2):538-547, 2021.