Expression of early growth responsive gene-1 in the visual cortex of monocular form deprivation amblyopic kittens

Abstract

Purpose The present study compared the expression of early growth responsive gene-1 (Egr-1) in visual cortex between amblyopia kittens and normal kittens, and to explore the role of Egr-1 in the pathogenesis of amblyopia. Methods A total of 20 healthy kittens were randomly divided into deprivation group and control group with 10 kittens in each group. Raised in natural light, and covered the right eye of the deprived kittens with a black opaque covering cloth. Pattern visual evoked potentials (PVEP) were measured before and at the 1st, 3rd and 5th week after covering in all kittens. After the last PVEP test, all kittens were killed. The expression of Egr-1 in the visual cortex of the two groups was compared by immunohistochemistry and in situ hybridization. Results PVEP detection showed that at the age of 6 and 8 weeks, the P100 wave latency in the right eye of deprivation group was higher than that in the left eye of deprivation group (P < 0.05) and the right eye of control group (P < 0.05), while the amplitude decreased (P < 0.05). The number of positive cells (P < 0.05) and mean optical density (P < 0.05) of Egr-1 protein expression in visual cortex of 8-week-old deprivation group were lower than those of normal group, as well as the number (P < 0.05) and mean optical density of Egr-1 mRNA-positive cells (P < 0.05). Conclusions Monocular form deprivation amblyopia can lead to the decrease of Egr-1 protein and mRNA expression in visual cortex, and then promote the occurrence and development of amblyopia.

Expression of early growth responsive gene-1 in the lateral geniculate body of kittens with amblyopia caused by monocular form deprivation

“…23,24 In this study, in order to increase the credibility of successful modelling of amblyopia model, we measured the left eye of form deprivation group in the PVEP test as a self-control. After 3 weeks of form deprivatization of kittens, the P100 wave amplitude of the deprivated eye (right eye) decreased substantially but the latency was prolonged, which was consistent with the findings of the previous studies, 22,[24][25][26] demonstrating successful development of the form deprivation amblyopia model. Immediate-early genes (IEGs) 27 are an important class of proto oncogenes that can encode several structural proteins, signal molecules and transfer factors, and their expression have been closely related to the maintenance of both synaptic plasticity and cognitive process (especially learning and memory).…”

“…23,24 In this study, in order to increase the credibility of successful modelling of amblyopia model, we measured the left eye of form deprivation group in the PVEP test as a self-control. After 3 weeks of form deprivatization of kittens, the P100 wave amplitude of the deprivated eye (right eye) decreased substantially but the latency was prolonged, which was consistent with the findings of the previous studies, 22,24–26 demonstrating successful development of the form deprivation amblyopia model.…”

“…18,19 A number of previous studies have demonstrated that the sensitive period of visual development of felines is generally 4–16 weeks old, whereas the peak of the critical period of visual development plasticity is at 4 weeks of age and extends until 12 weeks old, and after 12 weeks, the visual plasticity can decrease significantly, or even disappear completely. 20,21 Hence, monocular form deprivation was applied on three-week-old kittens by employing the loop covering method 16,22 to establish an amblyopia model. The loop covering method has been developed on the basis of traditional eyelid suture.…”

ARC/Arg3.1 expression in the lateral geniculate body of monocular form deprivation amblyopic kittens

“…Place the kitten 40 cm away from the vertical line in the center of the display screen, and adjust the head position so that its visual axis is perpendicular to the screen. Set the program of Reti-Port/Scan 21B (Roland Consult Stasche Finger Gmbh), select the chessboard flip mode, the time–frequency 1 Hz, 0.3 cpd mode, a contrast of 97%, superimposed 64 times and sampling time of 300 ms [ 15 ]. The test was repeated 3 times for each eye of each kitten and the average value was obtained.…”