Rheumatoid arthritis (RA) is a common autoimmune disease linked to chronic inflammation. Dysbiosis of the gut microbiota has been proposed to contribute to the risk of RA, and a large number of researchers have investigated the gut-joint axis hypothesis using the collagen-induced arthritis (CIA) rats. However, previous studies mainly involved short-term experiments; very few used the CIA model to investigate changes in gut microbiota over time. Moreover, previous research failed to use the CIA model to carry out detailed investigations of the effects of drug treatments upon inflammation in the joints, hyperplasia of the synovium, imbalance in the ratios of Th1/Th2 and Th17/Treg cells, intestinal cytokines and the gut microbiota following long-term intervention. In the present study, we carried out a 16-week experiment to investigate changes in the gut microbiota of CIA rats, and evaluated the modulatory effect of total glucosides of paeony (TGP), an immunomodulatory agent widely used in the treatment of RA, after 12 weeks of administration. We found that taxonomic differences developed in the microbial structure between the CIA group and the Control group. Furthermore, the administration of TGP was able to correct 78% of these taxonomic differences, while also increase the relative abundance of certain forms of beneficial symbiotic bacteria. By the end of the experiment, TGP had reduced body weight, thymus index and inflammatory cell infiltration in the ankle joint of CIA rats. Furthermore, the administration of TGP had down-regulated the synovial content of VEGF and the levels of Th1 cells and Th17 cells in CIA rats, and up-regulated the levels of Th2 cells and Treg cells. The administration of TGP also inhibited the levels of intestinal cytokines, secretory immunoglobulin A (SIgA) and Interferon-γ (IFN-γ). In conclusion, the influence of TGP on dynamic changes in gut microbiota, along with the observed improvement of indicators related to CIA symptoms during 12 weeks of administration, supported the hypothesis that the microbiome may play a role in TGP-mediated therapeutic effects in CIA rats. The present study also indicated that the mechanism underlying these effects may be related to the regulation of intestinal mucosal immunity remains unknown and deserves further research attention.

Shaoyao-Gancao Tang (SGT) is a traditional Chinese medicine formulation. It has been used to treat kinds of pain and to alleviate asthma in clinic. However, the mechanism of action is not known. To investigate the anti-asthma effect of SGT involving modulation of the T-helper type 1 (Th1) Th1/Th2 ratio in the gut-lung axis and alteration of the gut microbiota (GM) in rats with ovalbumin (OVA)-induced asthma. The main constituents of SGT were analyzed by high-performance liquid chromatography (HPLC). A model of asthma was established in rats by OVA-induced allergen challenge. Rats suffering from asthma (RSAs) were treated with SGT (2.5, 5.0 and 10.0 g/kg), dexamethasone (1 mg/kg) or physiologic saline for 4 weeks. The level of immunoglobulin (Ig)E in bronchoalveolar lavage fluid (BALF) and serum was determined by enzyme-linked immunosorbent assay. Histology of lung and colon tissues was investigated using staining (hematoxylin and eosin and periodic acid-Schiff). The Th1/Th2 ratio and levels of cytokines (interferon (IFN)-γ and interleukin (IL)-4) in the lung and colon were detected by immunohistochemistry. The GM in fresh feces was analyzed by 16 S rRNA gene sequencing. Twelve main constituents (gallic acid, albiflorin, paeoniflorin, liquiritin apioside, liquiritin, benzoic acid, isoliquiritin apioside, isoliquiritin, liquiritigenin, glycyrrhizic acid, isoliquiritigenin and glycyrrhetinic acid) of SGT were simultaneously determined by HPLC. SGT treatment (5.0 and 10.0 g/kg) was found to reduce the IgE level (a vital marker of hyper-responsiveness) in BALF and serum, improve typical morphological changes (inflammatory-cell infiltration and goblet cell metaplasia) in the lung and colon, alleviate airway remodeling (including bronchiostenosis and basement membrane-thickening) in the lung, significantly decrease the IL-4 level and increase the IFN-γ level in the lung and colon, which led to restoration of the IFN-γ/IL-4 ratio. The dysbiosis and dysfunction of GM in RSAs were modulated by SGT. The abundance of bacteria of the genera Ethanoligenens and Harryflintia was increased in RSAs and was decreased upon SGT treatment. The abundance of Family_XIII_AD3011_group was decreased in RSAs and increased upon SGT treatment. Moreover, SGT therapy increased the abundance of bacteria of the genera Ruminococcaceae_UCG-005 and Candidatus_Sacchrimonas, and decreased that of Ruminococcus_2 and Alistipes. SGT ameliorated rats with OVA-induced asthma via regulation of the Th1/Th2 ratio in the lung and gut, and modulated the GM.

In order to enhance oral bioavailability and liver targeting delivery of silybin, two amphiphilic hyaluronic acid derivatives, hyaluronic acid-deoxycholic acid (HA-adh-DOCA) and hyaluronic acid-glycyrrhetinic acid (HA-adh-GA) conjugates, were designed and synthesized. Silybin was successfully loaded in HA-adh-DOCA and HA-adh-GA micelles with high drug-loading capacities (20.3% ± 0.5% and 20.6% ± 0.6%, respectively). The silybin-loaded micelles were spherical in shape with the average size around 130 nm. In vitro release study showed that two silybin-loaded micelles displayed similar steady continued-release pattern in simulated gastrointestinal fluids and PBS. Single-pass intestinal perfusion studies indicated that silybin-loaded micelles were absorbed in the whole intestine and transported via a passive diffusion mechanism. Compared with suspension formulation, silybin-loaded HA-adh-DOCA and HA-adh-GA micelles achieved significantly higher AUC and C_max level. Moreover, liver targeting drug delivery of micelles was confirmed by in vivo imaging analysis. In comparison between the two micellar formulations, HA-adh-GA micelles possessed higher targeting capacity than HA-adh-DOCA micelles, owing to the active hepatic targeting properties of glycyrrhetinic acid. In the treatment of acute liver injury induced by CCl₄, silybin-loaded HA-adh-GA micelles displayed better effects over suspension control and silybin-loaded HA-adh-DOCA micelles. Overall, pharmaceutical and pharmacological indicators suggested that the HA-adh-GA conjugates can be successfully utilized for liver targeting of orally administered therapeutics.

Chronic migraine (CM) is a highly disabling and burdensome disease. Wuzhuyu decoction (WZYD), a clinical used formula to treat and prevent episodic migraine and CM, has been reported to relieve the hyperalgesia of CM and increase brainstem and blood serotonin (5-hydroxytryptamine, 5-HT) in migraine model rats in previous studies; yet the mechanism is unclear. This study aimed to observe the hyperalgesia relief effect of WZYD and investigate the mechanistic association with the regulation on central and peripheral 5-HT. WZYD with different doses (3.372, 1.686 and 0.843 g/kg∙d) and the positive drug - sumatriptan (5.83 mg/kg∙3 d) were intragastrically administered in inflammatory soup (IS)-induced CM model rats, respectively. Hyperalgesia was assessed by facial mechanical withdrawal threshold and tail-flick latency. 5-HT was determined by ELISA. Western blot analysis, immunohistochemistry and immunofluorescence determination, and 16S rRNA gene sequencing were performed. WZYD significantly relieved the hyperalgesia by elevating the facial mechanical withdrawal threshold and tail-flick latency. In WZYD groups, increased 5-HT and decreased calcitonin gene-related peptide in both the brainstem and plasma, downregulated TNF-α, IL-1β, and c-fos expression in the brainstem were observed in dose-dependent manner. Interestingly, 5-HT in colon tissues were also observed, which is associated with upregulating tryptophan hydroxylase, serotonin transporter and Piezo1 expression and increasing 5-HT and chromogranin A in enterochromaffin cells. Disorder of the microbiota, function and metabolism was correlated with 5-HT synthesis. WZYD could regulate the abundance of Anaerostipes and Acidifaciens. WZYD has the pharmacological effect on relieving hyperalgesia in CM model rats, possibly by affecting central and peripheral 5-HT.