RESUMO
Obesity, associated with the intake of a high-fat diet (HFD), and anxiety are common among those living in modern urban societies. Recent studies suggest a role of microbiome-gut-brain axis signaling, including a role for brain serotonergic systems in the relationship between HFD and anxiety. Evidence suggests the gut microbiome and the serotonergic brain system together may play an important role in this response. Here we conducted a nine-week HFD protocol in male rats, followed by an analysis of the gut microbiome diversity and community composition, brainstem serotonergic gene expression (tph2, htr1a, and slc6a4), and anxiety-related defensive behavioral responses. We show that HFD intake decreased alpha diversity and altered the community composition of the gut microbiome in association with obesity, increased brainstem tph2, htr1a and slc6a4 mRNA expression, including in the caudal part of the dorsomedial dorsal raphe nucleus (cDRD), a subregion previously associated with stress- and anxiety-related behavioral responses, and, finally, increased anxiety-related defensive behavioral responses. The HFD increased the Firmicutes/Bacteroidetes ratio relative to control diet, as well as higher relative abundances of Blautia, and decreases in Prevotella. We found that tph2, htr1a and slc6a4 mRNA expression were increased in subregions of the dorsal raphe nucleus in the HFD, relative to control diet. Specific bacterial taxa were associated with increased serotonergic gene expression in the cDRD. Thus, we propose that HFD-induced obesity is associated with altered microbiome-gut-serotonergic brain axis signaling, leading to increased anxiety-related defensive behavioral responses in rats.
Assuntos
Ansiedade , Eixo Encéfalo-Intestino , Dieta Hiperlipídica , Microbioma Gastrointestinal , Animais , Masculino , Dieta Hiperlipídica/efeitos adversos , Microbioma Gastrointestinal/fisiologia , Ansiedade/microbiologia , Eixo Encéfalo-Intestino/fisiologia , Ratos , Ratos Sprague-Dawley , Obesidade/microbiologia , Obesidade/psicologia , Obesidade/metabolismo , Transdução de Sinais/fisiologia , Comportamento Animal/fisiologiaRESUMO
Obesity, associated with the intake of a high-fat diet (HFD), and anxiety are common among those living in modern urban societies. Recent studies suggest a role of microbiome-gut-brain axis signaling, including a role for brain serotonergic systems in the relationship between HFD and anxiety. Evidence suggests the gut microbiome and the serotonergic brain system together may play an important role in this response. Here we conducted a nine-week HFD protocol in male rats, followed by an analysis of the gut microbiome diversity and community composition, brainstem serotonergic gene expression (tph2, htr1a, and slc6a4), and anxiety-related defensive behavioral responses. We show that HFD intake decreased alpha diversity and altered the community composition of the gut microbiome in association with obesity, increased brainstem tph2, htr1a and slc6a4 mRNA expression, including in the caudal part of the dorsomedial dorsal raphe nucleus (cDRD), a subregion previously associated with stress- and anxiety-related behavioral responses, and, finally, increased anxiety-related defensive behavioral responses. The HFD increased the Firmicutes/Bacteroidetes ratio relative to control diet, as well as higher relative abundances of Blautia, and decreases in Prevotella. We found that tph2, htr1a and slc6a4 mRNA expression were increased in subregions of the dorsal raphe nucleus in the HFD, relative to control diet. Specific bacterial taxa were associated with increased serotonergic gene expression in the cDRD. Thus, we propose that HFD-induced obesity is associated with altered microbiome-gut-serotonergic brain axis signaling, leading to increased anxiety-related defensive behavioral responses in rats.
RESUMO
PURPOSE: To describe the shape of a biplanar thumb metacarpal (MC) head and identify how it differs morphologically from previously described flat and round MC heads. METHODS: Lateral radiographs of the thumb were collected retrospectively from our patient database. Patients were included in the study if they had an appropriate lateral radiograph, met the age criteria (range; 18-75 years), and did not have severe metacarpophalangeal (MCP) joint arthritis. Metacarpal heads were categorized as flat or round by dividing the distance measured from the volar to the dorsal edge of the articular surface by the radius of curvature of the articular surface. A ratio of 1.7 or greater indicated a round MC head, whereas a ratio of less than 1.7 indicated a flat MC head. RESULTS: Among the 210 study participants, 110 were female and the average age was 47.3 years. During the measurement and classification process, it was determined by a board-certified hand surgeon that a subset of MCs did not meet the criteria for being categorized as either flat or round because of the inability to appropriately measure the radius of curvature of the MCP joint. Of the participants 113, 79, and 18, were classified as having either round, flat, or biplanar MC head shapes, respectively. CONCLUSIONS: We have identified a third, biplanar MC head shape. The biplanar head shape is more triangular and has two distinct planes on the articular surface that converge into an apex. CLINICAL RELEVANCE: The shape of the MC head has been shown to influence the range of motion of the MCP joint which may have an influence on the types of injuries that occur at the MCP joint. Further studies are required to understand how shape classification of MC heads may be useful and relevant to range of motion and risk of injury.