Establishment and evaluation of a stress depression model induced by light and dampness on mice / 中华行为医学与脑科学杂志

ABSTRACT

Objective@#To establish a novel stress-induced depression model by changing the lighting conditions and continuously damping cushion (L-D).@*Methods@#The L-D stress depression animal model was established in C57BL / 6 mice with body weight of 18-22 g. Seventy-five mice with the horizontal and vertical scores higher than 30 and less than 120 in open field test were employed.In the research of model construction, mice were randomly divided into three groups control group (n=9), chronic unpredictable mild stress(CUMS) model group (n=10) and L-D model group (n=9). In the drug intervention experiments, mice were randomly divided into five groups control group (n=9), chronic unpredictable mild stress(CUMS) model group (n=10), L-D model group (n=9), CUMS+ fluoxetine group (n=10) and L-D model+ fluoxetine group (n=9). Open field test, forced swimming test and sucrose preference test were used to evaluate the degree of depression in animals.@*Results@#(1) In the open field test, the horizontal score of CUMS model group (67.20±5.81) and the L-D model group (52.56±19.05) were significantly lower than that of the control group (76.44±9.22) (t=2.645, t=3.387, both P<0.05). And horizontal score of the L-D model was significantly lower than that of the CUMS model (t=2.321, both P<0.05). In forced swimming experiment, compared with the control group ((39.67±21.12)s), the immobility time of the CUMS model group ((60.90±10.34)s) and the L-D model group ((74.89±16.10)s) were significantly prolonged (t=2.831, 3.979, both P<0.05). The immobility time of the L-D model group was also significantly higher than that of the CUMS model group (t=2.278, P<0.05). In the sucrose preference experiment, the percentage of sucrose preference in CUMS model group ((72±7)%) and L-D model group ((65±5)%) was lower than that in the control group ((81±12)%) (t=2.195, 3.875, both P<0.05). The percentage of sucrose preference of L-D model group was significantly higher than that of CUMS model group (t=2.286, P<0.05). (2) After intervention with antidepressants, the horizontal scores of the CUMS model group (65.60±6.43) and the L-D model group (54.33±14.67) were significantly lower than that of the control group (75.78±8.27) in open field test (t=3.011, t=3.861, both P<0.05), and the score of L-D group was lower than that of CUMS group(t=2.235, P<0.05). The vertical score of the L-D model group (33.44±4.54) was significantly lower than that of the control group (39.22±5.56) (t=2.553, P<0.05). There was significant increase in the level score and vertical score of CUMS model and L-D model after fluoxetine intervention (t=3.090, t=2.692, both P<0.05), and significant twist in the vertical score of CUMS model and L-D model (t=2.681, t=2.354; both P<0.05). In the forced swimming experiment, the immobility time of the L-D model((64.11±13.06)s) was significantly longer than that of the control group ((42.00±13.77)s) (t=3.494, P<0.05). The immobility time of CUMS model and L-D model mice was significantly longer than that of non-intervention group (t=2.137, 2.940, both P<0.05). After the intervention of fluoxetine, there was no significant difference between the CUMS group, L-D group, the control group(all P>0.05).@*Conclusion@#Changing the lighting conditions and continuously damping cushion is a new method to establish mice model with depression behavior.Shorter modeling duration and simple operation are the main advantages of this model.