Allergic diseases is a major worldwide health problem.The abnormal structure of intestinal microbiota is closely related to the occurrence and development of allergic diseases.The formation of intestinal microbiota in early life is influenced by many factors,such as the mode of delivery,feeding methods,the addition of probiotics or prebiotics,heredity and so on.The abnormal structure of intestinal microbiota in early life is an important factor influencing the occurrence of allergic diseases in the later life.In this paper, we will discuss the relationship between the abnormal structure of intestinal microbiota in early life and allergic diseases with the latest literature.

Objective:To explore the effects of Huatan Tongluo Decoction （HTTLD） on the morphology and function of brain tissues and intestine in rats with cerebral ischemia/reperfusion based on the gut-brain axis. Method:Sixty SPF male rats were randomly divided into a sham operation group， a model group， high- （28.66 g·kg^-1）， medium- （14.33 g·kg^-1）， and low-dose （7.16 g·kg^-1） HTTLD groups， and an edaravone （4 g·kg^-1）+Clostridium butyricum （5.0×10⁸ cfu·mL^-1） group. The model was established by focal cerebral ischemia/reperfusion in rats. The drugs were administered by gavage. The brain tissue injury was determined by neurological deficit score and 2，3，5-triphenyl tetrazolium chloride （TTC） staining. The effect of cerebral ischemia/reperfusion on intestinal motility was assessed by the propulsion rate of small intestine. The intestinal mucosal cell damage was evaluated by the pathomorphological examination of the duodenal mucosa. Enzyme-linked immunosorbent assay （ELISA） was used to determine the content of D-lactate （D-LAC）， diamine oxidase （DAO）， and bacterial endotoxin （lipopolysaccharide， LPS） in serum. Western blot was used to detect the expression of Occludin， Claudin-5， and zonula occludens 1 （ZO-1） in the duodenum. Result:After cerebral ischemia/reperfusion， rats developed neurological deficit symptoms. The neurological deficit score in the model group was higher than that in the sham operation group （P<0.01）. Compared with the model group， the high- and medium-dose HTTLD groups could relieve the symptoms of neurological deficits and lower neurological deficit scores （P<0.01）. The results of TTC staining showed that the model group presented obvious infarcts in brain tissues compared with the sham operation group （P<0.01）. The cerebral infarction volumes of HTTLD groups were reduced compared with that in the model group （P<0.01）， especially the high-dose HTTLD group， and the effect was dose-dependent. Furthermore， the propulsion rate of small intestine in the model group was significantly reduced compared with that in the sham operation group （P<0.01）. Compared with the model group， HTTLD groups could increase propulsion rates of small intestine （P<0.01）， especially the high-dose HTTLD group， and the effect was dose-dependent. After cerebral ischemia/reperfusion， obvious duodenal mucosal damage could be observed， which was relieved after the administration of HTTLD. Western blot results showed that the protein expression of ZO-1， Occludin， and Claudin-5 in the model group was reduced compared with that in the sham operation group （P<0.01）. Compared with the model group， the HTTLD groups could up-regulate the expression of ZO-1， Occludin， and Claudin-5 to varying degrees （P<0.05， P<0.01）， especially the high-dose HTTLD group. ELISA showed that the serum D-LAC， DAO， and LPS of the model group were elevated compared with those in the sham operation group （P<0.01）. Compared with the model group， the HTTLD groups showed reduced D-LAC and DAO （P<0.05， P<0.01）， and the medium- and high-dose HTTLD groups showed reduced LPS （P<0.05， P<0.01）， especially the high-dose HTTLD group. Conclusion:After cerebral ischemia/reperfusion， the rats showed damaged brain tissues， neurological dysfunction， intestinal mucosal injury， weakened intestinal motility， and destroyed the intestinal mucosal barrier. HTTLD can protect against brain-gut axis injury after cerebral ischemia/reperfusion by reducing the damage on brain tissues and gastrointestinal mucosa， relieving the symptoms of neurological deficits， promoting gastrointestinal motility， improving intestinal barrier function， and reducing the release of intestinal bacterial metabolites or poisons.