Effects of long-term social isolation on central, behavioural and metabolic parameters in middle-aged mice

Author(s)

Benfato, Izabelle Dias ^[1] ; Silvares Quintanilha, Ana Carolina ^[1] ; Henrique, Jessica Salles ^[2] ; Souza, Melyssa Alves ^[1] ; Rosario, Barbara dos Anjos ^[1] ; Araujo Beserra Filho, Jose Ivo ^[3] ; Oliveira Santos, Robson Luiz ^[4] ; Ribeiro, Alessandra Mussi ^[5] ; Maluf, Luciana Le Sueur ^[5] ; Machado de Oliveira, Camila Aparecida ^[5]

Affiliation

^[1] Fed Univ Sao Paulo UNIFESP, Interdisciplinary Grad Program Hlth Sci, Sao Paulo - Brazil

^[2] Fed Univ Sao Paulo UNIFESP, Neurol Neurosci Grad Program, Sao Paulo - Brazil

^[3] Fed Univ Sao Paulo UNIFESP, Pharmacol Grad Program, Sao Paulo - Brazil

^[4] Fed Univ Sao Paulo UNIFESP, Undergrad Phys Educ, Sao Paulo - Brazil

^[5] Fed Univ Sao Paulo UNIFESP, Inst Hlth & Soc, Dept Biosci, Sao Paulo - Brazil

• Document type: Journal article
• Source: Behavioural Brain Research; v. 417, JAN 24 2022.
• Web of Science Citations: 1

Abstract

Social isolation gained discussion momentum due to the COVID-19 pandemic. Whereas many studies address the effects of long-term social isolation in post-weaning and adolescence and for periods ranging from 4 to 12 weeks, little is known about the repercussions of adult long-term social isolation in middle age. Thus, our aim was to investigate how long-term social isolation can influence metabolic, behavioural, and central nervous systemrelated areas in middle-aged mice. Adult male C57Bl/6 mice (4 months-old) were randomly divided into Social (2 cages, n = 5/cage) and Isolated (10 cages, n = 1/cage) housing groups, totalizing 30 weeks of social isolation, which ended concomitantly with the onset of middle age of mice. At the end of the trial, metabolic parameters, short-term memory, anxiety-like behaviour, and physical activity were assessed. Immunohistochemistry in the hippocampus (AFosB, BDNF, and 8OHDG) and hypothalamus (AFosB) was also performed. The Isolated group showed impaired memory along with a decrease in hippocampal AFosB at dentate gyrus and in BDNF at CA3. Food intake was also affected, but the direction depended on how it was measured in the Social group (individually or in the group) with no alteration in AFosB at the hypothalamus. Physical activity parameters increased with chronic isolation, but in the light cycle (inactive phase), with some evidence of anxietylike behaviour. Future studies should better explore the timepoint at which the alterations found begin. In conclusion, long-term social isolation in adult mice contributes to alterations in feeding, physical activity pattern, and anxiety-like behaviour. Moreover, short-term memory deficit was associated with lower levels of hippocampal AFosB and BDNF in middle age. (AU)

• FAPESP's process: 17/26075-8 - Central control of spontaneous physical activity in mice submitted or not to caloric restriction during aging process
• Grantee: Izabelle Dias Benfato
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 17/04528-0 - Evaluation of spontaneous physical activity and compensatory behavior in experimental model and obese individuals engaged in an interdisciplinary program for obesity treatment
• Grantee: Camila Aparecida Machado de Oliveira
• Support type: Regular Research Grants
• FAPESP's process: 11/05932-3 - Molecular mechanisms involved in the modulation of spontaneous physical activity and development of obesity
• Grantee: Camila Aparecida Machado de Oliveira
• Support type: Research Grants - Young Investigators Grants