Gut Pathophysiology in Mouse Models of Social Behavior Deficits

• Main Author: Scott, Kyla
• Format: Others
• Published: Digital Commons @ East Tennessee State University 2020
• Subjects: Microbiome; Autism; Gut; Pathophysiology; Intestine; Short chain fatty acid; Anatomy; Bacterial Infections and Mycoses; Digestive System; Digestive System Diseases; Immune System Diseases; Medical Anatomy; Medical Biochemistry; Medical Microbiology; Medical Pathology; Microbiology; Tissues; Virus Diseases
• Online Access: https://dc.etsu.edu/honors/544; https://dc.etsu.edu/cgi/viewcontent.cgi?article=1681&context=honors

Autism spectrum disorders (ASD) encompass neurodevelopment disorders characterized by atypical patterns of development that impact multiple areas of functioning beginning in early childhood. The etiology of ASD is unknown and there are currently no preventative treatment options. Gastrointestinal symptoms are commonly associated comorbidities. The microbiota-gut-brain axis is a multidirectional communication chain that connects the central and enteric nervous system that relates brain function to peripheral intestinal functions. Changes within this axis have been postulated in ASD. For example, the “leaky gut theory” proposes that chronic inflammation is linked to alterations in the bacterial profiles of the gut microbiome and subsequent shifts in the amount and type of short-chain fatty acids produced can affect downstream neuronal development. Short-chain fatty acids are signaling molecules produced by bacteria that can trigger nerve afferents in the gut. Dysbiosis causes altered signaling patterns that can be identified by altered intestinal morphology. In this study, C57BL/6J control mice and three mouse models of social behavioral deficits were used to investigate markers of intestinal pathophysiology. Fecal and intestinal samples were collected from adult wild type control mice and the social deficit groups of BTBR genetic knockout mice, C57BL/6J mice injected with valproic acid, and C57BL/6J mice injected with polyinosinic–polycytidylic acid. Short-chain fatty acid profiles that included acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids were obtained from fecal samples to determine differences between the models and control mice. The profiles of the BTBR genetic knockout and valproic acid models were found to be significantly different from control mice. Additionally, postmortem intestinal ileum samples underwent hematoxylin and eosin identification procedures to determine the thickness of the tunica muscularis and tunica mucosa. The thickness of the tunica muscularis was reduced in the valproic acid group compared to the wild type control mice in early stages of development (p=0.0279). This research may illuminate developmental cues that attribute to autism spectrum disorders and may provide markers to assess future therapeutic treatments.