Anxiety and Depression Assessments in a Mouse Model of Congenital Blindness

Abstract

Previous studies have reported that visual impairment can affect the quality of life leading to mental health disorders. This study aimed to investigate associations between vision impairment, depression and anxiety using a mouse model of congenital blindness. We phenotyped 15 anophthalmic and 17 sighted adult mice in a battery of tests for anxiety and depression-like behaviors: open field test, elevated plus maze, coated test, splash test, and forced swim test. We found that: (1) Anxiety levels of the anophthalmic mice were significantly lower when compared with sighted mice, (2) Anophthalmic mice displayed more exploratory behaviors in a new environment than the sighted one, and (3) Depression levels between those groups were similar. In conclusion, this behavioral study showed that early visual deprivation lowers anxiety levels, associated with heightened exploratory activity, but does not induce depressive symptoms in a mouse model of congenital blindness, underlying several behavioral adaptations.

Keywords: anxiety; congenital blindness; depression; exploration; mice.

Figure 1

Anophthalmic and sighted mice assayed to depression-like behavioral tests, such as the Splash Test (A) : Mean (± SE) of (a) time spent (s) Grooming, (b) Latency (s) before the first grooming, (c) Grooming Frequency, (d) Distance traveled (cm) in the device for a 10 min-test; and the Forced Swim Test (B): (a) Immobility Time (s), (b) Distance traveled (cm), (c) Time spent climbing in the tank for a 6-min test, and the Suspension Tail test (C): Immobility Time (s) for a 6-min test (N = 15 and 17 mice/group, respectively ^***p < 0.001).

Figure 2

Anxiety-like behavioral tests. Anophthalmic and sighted mice assayed to the open-field test (A): (a) Mean (± SE) time spent (s) of grooming, (b) Latency before the first grooming (s), (c) Frequency of grooming, (d) Distance (cm) traveled in the device for a 5 min-test (N = 15 and 17 mice/group, respectively). Anophthalmic and sighted mice assayed to the Elevated-Plus Maze (B): (a) Mean (± SE) time spent (s) in open and closed arms, (b) Frequency in open and closed arms, (c) Distance (cm) traveled in the whole device for a 5 min-test (N = 15 and 17 mice/group, respectively; *p < 0.05; ***p < 0.001).