Avaliação do potencial psicobiótico de Bifidobacterium longum subsp. longum 51A e Lacticaseibacillus rhamnosus (64) em modelo experimental de depressão induzida por lipopolissacarídeo

• Ano de defesa: 2025
• Autor(a) principal: Natsumi Mizogami Santana
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ICB - DEPARTAMENTO DE MICROBIOLOGIA; Curso de Especialização em Microbiologia; UFMG
• Palavras-chave em Português: C57BL/6; LPS; Eixo microbiota-intestino-cérebro; Depressão; Ansiedade; Probiótico; Microbiologia; Depressão Ansiedade; Microbioma Gastrointestinal; Probióticos; Lipopolissacarídeos
• Link de acesso: http://hdl.handle.net/1843/82980

Depression is one of the most prevalent psychiatric disorders in the world. Despite numerous studies, there are still gaps in the knowledge of its pathophysiology. The pharmacological treatment faces challenges such as the delay in therapeutic effect accompanied by the rapid manifestation of side effects. Furthermore, a significant portion of patients does not respond to currently available drugs. In Brazil, it is estimated that the prevalence of depression is about 15.5%, reaching 20% among women. Considering the high prevalence and difficulties in treatment, there is a need for new therapeutic approaches. Changes in the microbiota have been suggested as a possible factor associated with depression, with an emphasis on microbiota modulation as a potential strategy for the development of new therapies. From this perspective, psychobiotics, which can be defined as probiotic capable of providing benefits to mental health, may contribute to safer and more effective treatments. Bifidobacterium longum subsp. longum 51A (B51A) and Lacticaseibacillus rhamnosus (64) (L64) are bacteria isolated from feces and breast milk, respectively, both having positive effects on cognition in preclinical trials. Considering this, the aim of this study was to evaluate the psychobiotic potential of B51A and L64 using C57BL/6 mice with depressive-like behavior induced by intraperitoneal (i.p.) administration of Escherichia coli O111:B4 lipopolysaccharide (LPS). In addition to behavioral tests to evaluate locomotion, cognition, depressive-like behavior, and anxiety-like behavior, immunological parameters in the spleen, liver, small intestine, and colon, measurement of brain-derived neurotrophic factor (BDNF) level in serum and brain, quantification of short-chain fatty acids (SCFAs) in cecal content, and secretory IgA in small intestine fluid were conducted. Moreover, the body weight, food intake, and clinical score were monitored. Female mice exhibited depressive-like behavior seven days after a single dose of 1.5 mg/Kg of LPS, without changes in the total distance traveled in the open field test. However, administration of either B51A or L64 was not effective in reducing immobility time in the forced swim test. This indicates that, despite the experimental model successfully induced depressive-like behavior, these strains did not show the expected therapeutic effects in this specific assay. Nevertheless, both strains increased hippocampal BDNF levels, suggesting a neuroprotective effect. In addition, the administration of L64 accelerated the recovery of animals exposed to LPS. These results indicate the need for further investigation into the therapeutic potential of these strains, possibly in different experimental models or with alternative administration protocols.