Agouti yellow mice simulating type 2 diabetes demonstrated depressive-like behavior, as well as changes in the brain that are not found in another well-studied line of laboratory mice with the same disease, which means that other pathways can be investigated in them the formation and course of the disease. An article about this was published in the journal Behavioral Brain Research .
The scientists evaluated Agouti yellow ‘s behavior using Porsolt’s classic forced swim test . In this experiment, the mouse is placed in a small deep tank of water. At first, the animal tries to get out, but after a while it feels that it cannot be done and freezes, saving strength. Periods of inactivity and activity alternate. Prolonged immobility of the animal in this test is believed to indicate depressive-like behavior, since most antidepressants increase the time of active resistance and decrease the time the animal does not move.
“In respect of mice is more correct to speak about depressive-like behavior, rather than depression, – says one of the authors of the article, researcher at the Institute of Cytology and Genetics of SB RAS, Doctor of Biological Sciences Nikita Hotskin . – Depression is a complex syndrome made up of a range of symptoms, most of which are likely unique to humans. In addition to physiological manifestations, it is characterized by such things as, for example, the lack of a sense of self-importance and thoughts of suicide. The mechanism of the formation of depressive behavior in animals is close to the mechanism of learned helplessness, when a person does not feel the connection between effort and result. “
In Agouti yellow mice, mobility in the Porsolt test was reduced in comparison with the control group. These animals also resist less in another test for depressive-like behavior, the tail hanging test. However, Agouti yellow performs well on cognitive testing, in contrast to the conventional line of obesity mice in a type 2 diabetes model lacking the leptin receptor.
“As it turned out, these lines have significant differences at the level of physiology,” says the scientist. – Agouti yellow mice have a reduced volume of the cerebral cortex, and the line with the absence of the leptin receptor has disturbances in a completely different region, in the hippocampus. It turns out that different internal mechanisms lead to the same external manifestations of the disease. As you know, you need to treat the cause of the disease, not the symptom, so it is very important to study different scenarios for the formation of depressive-like behavior. And in this regard, we have high hopes for the Agouti yellow line . ”