Abstract
Abstract: :
Purpose: Comparisons of retinal function across different mouse strains from different laboratories are frequently difficult because a standard electreoretinographic (ERG) protocol does not exist for mice. In this study, ERG responses obtained using a stanadard protocol are compared across eleven normal inbred mouse strains. Methods: Procedures for recording ERGs from mice have been described.1 ERGs were recorded from 11 normal inbred mouse strains (mean age 13+ 3 weeks) commonly used as background strains in studies of retinal function, including C57BL/6J, 129sv-1, c2J, BALB/cJ, CBA/CaJ, DBA/2J, DBA/1J, NZW/LacJ, NZW/BINJ, AKR/J, and LP/J. Intensity-response series were recorded to evaluate both rod- and cone- mediated function. Parameters derived from the ERG recordings included Vmax, k, RmP3, S, oscillatory potential (OPs) amplitudes, cone amplitudes, and rod- and cone- ERG thresholds. Results: Vmax across strains ranged from 194 µv (+73) to 391 (+88) µv, with CBA/CaJ and DBA/1J mice providing the lowest estimates and C57BL/6J and LP/J mice providing the highest (P < 0.05). Systematic variations in Vmax were observed across the remaining strains. The parameters k and rod ERG threshold yielded strong negative correlations with Vmax (P < 0.001), but OP amplitudes were poorly correlated (P = 0.39), resulting a different ordering of strains than that produced by Vmax. Cone-mediated amplitudes to bright flashes on rod-saturating background ranged from 55 (+15) µV for DBA/1J mice to 147 (+27) µv for c57BL/6J. Rod- and cone- mediated amplitudes and ERG thresholds were positively correlated (Ps < 0.01). The parameter RmP3, derived from the leading edge of the a-wave, was positively correlated with Vmax (P =0.02), although the relationship was generally weaker. The sensitivity parameters k and S were uncorrelated (P = 0.30), with log S relatively stable across strains, although occasional statistical differences occurred. Conclusions: A comparison of ERG responses across eleven normal inbred mouse strains revealed a range of differences in parameter estimates. The differences may reflect variations in the structure and organization of retinal cells across the different strains and underscores the need for comprehensive normative data by mouse strain. 1. Nusinowitz et al (2001). Electrophysiological Testing of the Mouse Visual System. In (Smith, R, Nishina, P. John, S (Eds). Systematic Evaluation of the Mouse Eye: Anatomy, Pathology and Biomethods.
Keywords: animal model • retina: distal(photoreceptors, horizontal cell • electroretinography: non-clinical