Joyce Chen ’23
Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects 1% of individuals worldwide. Although there has been extensive research done on ASD, its primary cause remains unknown. Scientists believe that it is the result of a wide variety of heritable and environmental factors. However, recent research has indicated that an altered gut microbiome caused by a poor diet can lead to neurodevelopmental abnormalities and changes in behavior. Dr. Kazi Afroz of Texas Tech University and a group of researchers investigated the underlying mechanisms governing autism-like behavior using mice models.
The researchers noted that a high salt diet (HSD) is typically the main cause of various health problems, including those that affect the gut microbiome. They hypothesized that HSD in the mother would directly affect the growing infant’s gut microbiome and ultimately lead to abnormal behaviors. For the study, male and female mice were mated and were split into two groups. One group was fed a high salt diet, while the control group was fed a natural diet. After the female mice gave birth, the researchers collected fecal samples from both the mothers and their offspring. These samples were inspected to see if any changes occurred in the gut microbiome. There were identical changes in the bacterial composition within the gut microbiomes of both mothers and their offspring, which indicated the transfer of these changes from parent to offspring. As the offspring mice developed, noticeable changes in locomotion began to occur in the male mice. In a marble burying test, the offspring had to bury marbles as the researchers analyzed repetitive behaviors. The offspring from the HSD-fed group buried a noticeably higher percentage of marbles compared to the offspring from the control group. To measure sociability, the researchers used a container with three chambers. One mouse was placed in one chamber, known as the social (S) chamber, while the non-social (NonS) chamber was kept empty. A mouse was placed in the middle of all three chambers while the team measured the amount of time it interacted with the S chamber. Offspring from the HSD-fed group showed little to no interest in the S chamber, while the control group offspring interacted with the S chamber for a longer period of time.
Dr. Afroz and her team’s study highlights the importance of diet and its impact on neurodevelopmental patterns in offspring. The study shows how the offspring from HSD-fed parents had hyperactive, compulsive, and antisocial behavior, which mirrors signs of ASD. Future studies will need to be done to determine the correlation between the gut bacteria and behavioral patterns.
 K. Afroz, et al., Altered gut microbiome and autism like behavior are associated with parental high salt diet in male mice. Sci Rep 11, 8364 (2021). Doi: 10.1038/s41598-021-87678-x