Soluble Dietary Fiber of Hawthorn Relieves Constipation Induced by Loperamide Hydrochloride by Improving Intestinal Flora and Inflammation, Thereby Regulating the Aquaporin Ion Pathway in Mice

Dietary fiber can be fermented and utilized by gut microbiota to reshape the gut microbiota, thereby alleviating constipation. This experiment mainly studied the physicochemical functions of hawthorn soluble dietary fiber (HSDF)and its effect and mechanism in alleviating constipation in mice. Forty-five mice were divided into blank control group C, model group M, positive control HS group, low-dose LHSDF group (1 g/kg/bw), and high-dose HHSDF group (2 g/kg/bw). The mice were modeled at a dose of 10 mg/kg/bw of loperamide hydrochloride for 7 days, while the remaining groups were orally administered an equal amount of distilled water and test samples. After continuous gavage for 45 days we performed a bowel movement test, and then continued gavage for 7 days and performed a small intestine propulsion test and indicator testing. The results showed that HSDF is mainly composed of galacturonic acid, belonging to the type I crystal structure, with a loose surface resembling a snowflake, a small molecular weight, and strong water-holding and antioxidant abilities. Animal experiments showed that compared with group M, HSDF significantly upregulated AQP3 and AQP8 by 52.67% and 164.54%, respectively, and downregulated AQP9 protein expression by 45.88%, thereby promoting intestinal peristalsis. It can also alleviate constipation by increasing the levels of excitatory hormones such as MTL, GAS, and SP in the gastrointestinal tract, and reducing the levels of inhibitory hormones such as SS, NO, and MDA. In addition, HSDF can reduce the levels of inflammatory factors such as IL-6 and PL-1 &beta:, increase the content of various short-chain fatty acids, alleviate intestinal inflammation, maintain intestinal integrity, and promote defecation. It can also promote the growth of probiotics such as Bacteroides, inhibit the growth of harmful bacteria such as Bifidobacterium and Lactobacillus, and alter the diversity of gut microbiota.