Effects of Tuina targeting different body parts on the behaviors and gut microflora of autistic spectrum disorder rat models

Abstract

Objective

To investigate the effects of Tuina targeting different body parts on the behaviors and gut microflora of rat models with valproic acid (VPA)-induced autistic spectrum disorder (ASD).

Methods

Twenty female Sprague Dawley (SD) rats with 12.5 d of pregnancy were randomly divided into VPA model group [intraperitoneal injection of VPA (600 mg/kg), n = 15] and saline group (intraperitoneal injection of equal amount of normal saline, n = 5). The offspring male rats injected with saline were secleted as control group. The offspring male rats injected with VPA were randomly divided into VPA, dorsal, and abdominal groups (n = 7 in each group). On the 21st day after birth, three-chamber social test, open field test, and marble-burying test were carried out to observe the social abilities, anxiety behaviors, and stereotypical behaviors of rats in the four groups. Rats in dorsal and abdominal groups underwent Tuina for 14 d, twice a day. On the 35th day, behavioral tests were conducted again, and intestinal contents were taken for species composition and structural analysis, as well as marker and differential species analysis.

Results

(i) According to behavioral observations, compared with VPA group, the social and movement time in the central open field of rats in dorsal group increased significantly (P < 0.05), and the number of buried marbles decreased markedly (P < 0.01), indicating improvement on their social abilities, anxiety behaviors, and stereotypical behaviors as consequences of dorsal Tuina; and the number of buried marbles was reduced as well in abdominal group when compared with VPA group (P < 0.05), suggesting the improvement on their stereotypical behaviors following abdominal Tuina. In the marble-burying test, the number of marbles buried in dorsal group was less than in abdominal group, and the stereotypical behaviors were improved more significantly (P < 0.05), and there were no significant differences in the three-chamber social and open field tests between the two groups (P >0.05). (ii) In accordance with intestinal microflora detection results, compared with VPA group, both dorsal and abdominal groups showed increased richness (P < 0.05) and elevated diversity (P < 0.05 in dorsal group and P < 0.01 in abdominal group) in intestinal microflora. The results of differential analysis indicated that at the phylum level, compared with VPA group, the relative abundance of Firmicutes in rats in abdominal group showed a significant reduction trend (P < 0.05); at the genus level, compared with VPA group, the relative abundance of Lactobacillus in rats in dorsal and abdominal groups decreased significantly (P < 0.05). Dorsal group also showed significant increase in the genus Blautia in the analysis of marker species compared with VPA group (P < 0.05).

Conclusion

Tuina impacted the behavior and gut microflora structure of ASD model rats. Dorsal intervention had a significant effect on social abilities, anxiety behaviors, and stereotypical behaviors of ASD model rats, while abdominal intervention only had an obvious effect on stereotypical behaviors. Both dorsal and abdominal interventions increased the richness and diversity of gut microflora of ASD model rats, with abdominal intervention improving the intestinal microbial diversity more significantly and resulting in a more uniform species distribution.