The Damaging Effect of Systemic Injection of Monosodium Glutamate (MSG) on the Development of Normal and Form‐Deprived Eyes of the Chick

Abstract

Glutamate has been implicated in ocular development. The present study aims to characterize the physical changes that occur as a result of systemic intake of monosodium glutamate (MSG). As MSG has also been suggested to play a part in myopia, its effect on form‐deprived eyes was also investigated. Form‐deprivation myopia (FDM) was induced by placing a black goggle over one eye of each chick. Neonatal chicks were injected with daily MSG (0.1, 1 and 10 mg/day) or saline control for 14 days intraperitoncally (n = 6–7 in all cases). The results show that MSG significantly reduced the eye weight (EW), ocular length (OL), and equatorial diameter (ED) of the normal (i.e. with MSG treatment but not form‐deprived) ocular growth (mean ± s.e.m, MSG dose in parenthesis): EW, 0.90 ± 0.02 vs. 0.81 ± 0.05 (0.1), 0.78 ± 0.04 (1), 0.83 ± 0.04 (10); OL, 1.02 ± 0.03 vs. 0.94 ± 0.03 (0.1), 0.95 ± 0.01 (1), 0.97 ± 0.02 (10); ED, 1.36 ± 0.01 vs. 1.30 ± 0.02 (0.1), 1.28 ± 0.02 (1), 1.33 ± 0.03 (10). As a result of FDM, these me...