Both cathartic colon （CC） and cathartic-dependent constipation （CDC） are caused by the abuse of stimulant laxatives， while their concepts are not completely the same.Starting from the disease name of CC， this article traced the origin and evolution of the concept of CC， summarizes and compared the similarities and differences between CC， CDC， and slow transit constipation （STC）， and called for strict differentiation among the three.Furthermore， this article explored the specific contents of Western medicine clinical subtypes and traditional Chinese medicine （TCM） syndrome differentiation of CDC and delved into the TCM pathogenesis of CDC according to both literature and clinical practice.The relationship between clinical subtypes and TCM syndromes was established， and the syndrome characteristics of CDC of different clinical subtypes and TCM syndromes were summarized.The recommended prescriptions for corresponding syndromes were listed.A systematic CDC diagnosis and treatment approach of "clinical subtypes-syndrome differentiation-syndrome characteristics-recommended prescriptions" was thus formed.Additionally， the paper provides an overview of current research on CDC in both Western medicine and TCM contexts， identifies future research directions， and suggests research pathways for refining and advancing CDC studies.

ObjectiveTo observe the clinical efficacy of the Yiqi Yangyin Huoxue prescription （YYHP） in the treatment of cathartic colon （CC） and its effects on fecal short-chain fatty acids （SCFAs）， and to explore the correlations among CC severity indicators and between these indicators and patient history. MethodsAccording to the inclusion and exclusion criteria， 98 patients meeting the diagnostic criteria of both traditional Chinese and Western medicine for CC with the syndrome of Qi-Yin deficiency complicated by blood stasis were randomly assigned to an observation group and a control group. The observation group received YYHP granules， while the control group received lactulose. Both medications were administered twice daily， one sachet each time， half an hour after breakfast and dinner， with a treatment course of 8 weeks. The primary constipation symptom score， Patient Assessment of Constipation Quality of Life （PAC-QOL） score， and TCM syndrome score were assessed before and after treatment and at the 8^th week after the end of treatment. The overall clinical effective rate， as well as the efficacy attenuation index and degree， were evaluated. Fecal SCFA levels were measured using gas chromatography-mass spectrometry （GC-MS）. Spearman correlation analysis was performed to explore the correlations among CC severity indicators and between these indicators and patient history. ResultsThe overall clinical effective rate in the observation group （95.83%） was higher than that in the control group （78.72%） （P<0.05）. After treatment， the total scores for primary constipation symptoms， PAC-QOL， and TCM syndromes decreased in both groups （P<0.05）， with more significant reductions in the observation group （P<0.05）. The severity of all primary constipation symptoms was alleviated in both groups （P<0.05）. In terms of "excessive straining and difficult defecation"， "anal heaviness， incomplete evacuation， and bloating sensation"， "abdominal distension"， and "defecation frequency"， the observation group showed better efficacy than the control group （P<0.05）. Scores of the four PAC-QOL dimensions and the scores and severity of primary and secondary TCM symptoms were reduced in both groups （P<0.05）， with more significant reductions in the observation group （P<0.05）. After treatment， acetic acid， propionic acid， butyric acid， and total SCFAs in the observation group increased significantly （P<0.05）. The efficacy attenuation index and degree in the observation group were lower than those in the control group （P<0.05）. No severe adverse reactions occurred in either group， and there was no statistically significant difference in the incidence of adverse reactions between the two groups. Positive correlations of varying degrees were observed among the total scores of primary constipation symptoms， PAC-QOL， and TCM syndromes， as well as between these scores and the history of stimulant laxative use， disease duration， and age. ConclusionYYHP can effectively alleviate the primary constipation symptoms in CC patients， improve quality of life， and ameliorate TCM syndromes， with good safety. It also has the advantage of a lower rebound degree after drug withdrawal， and its mechanism may be related to increasing fecal SCFA levels. Long-term abuse of stimulant laxatives may aggravate the severity of CC and prolong the disease course.

ObjectiveTo evaluate and analyze the syndrome characteristics of Qi and Yin deficiency accompanied by Qi stagnation and blood stasis in a rhein-induced cathartic colon （CC） rat model. MethodsTwenty-four rats were divided into a normal group and a model group （CC group）. The rats were administered equal volumes of physiological saline or 2% rhein suspension by gavage to establish the model over three cycles （approximately 118 days）. The first cycle lasted 46 days， with a dosage of 12 mL·kg^-1·d^-1， administered every other day. The second cycle lasted 37 days， with a dosage of 12 mL·kg^-1·d^-1， administered for 5 consecutive days followed by 2 days of cessation. The third cycle lasted 35 days， with a dosage of 16 mL·kg^-1·d^-1， also administered for 5 consecutive days followed by 2 days of cessation. Each cycle ended when 80% of the rats no longer exhibited loose stools. Body mass， 24 h food intake， coat condition， and coat red （R）， green （G）， and blue （B） values were recorded. The open field test （OFT） was used to measure the total distance traveled to evaluate Qi deficiency. The body mass coefficient and 24 h water intake were recorded to assess Yin deficiency. The sucrose preference test （SPT） was used to determine the sucrose preference rate （SPR）， and the average speed in OFT was measured to evaluate depressive status （liver depression and Qi stagnation）. Tongue images and their R， G， and B values were recorded. Whole blood viscosity （WBV） and plasma viscosity （PV） were measured using an automatic hemorheological analyzer to evaluate blood stasis. A carbon ink propulsion test was performed to determine the intestinal transit rate （ITR） for disease model evaluation. Hematoxylin-eosin （HE） staining was used to observe histopathological changes in the colon. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression of transient receptor potential ankyrin 1 （TRPA1） and tryptophan hydroxylase 1 （TPH1） in colon tissue. Western blot was used to detect the protein expression of TRPA1 and TPH1. ResultsIn terms of syndrome indicators， compared with the normal group， the body mass of the CC group decreased （P<0.05）， while 24 h food intake increased （P<0.01）. The coats of the CC group appeared withered， disheveled， and dull， and the R， G， and B values of the coat decreased （P<0.01）. The total distance traveled in OFT decreased （P<0.01）. The body mass coefficient decreased （P<0.01）， while 24 h water intake increased （P<0.05， P<0.01）. The SPR decreased （P<0.01）， and the average speed in OFT slowed （P<0.01）. The tongue appeared dark red， and the R， G， and B values of tongue images decreased （P<0.01）. WBV and PV increased （P<0.01）. Regarding disease indicators， compared with the normal group， the ITR decreased in the CC group （P<0.01）. Pathologically， HE staining showed necrosis and shedding of colonic mucosal epithelial cells， disruption of mucosal continuity， and infiltration of inflammatory cells in the lamina propria in the CC group. Semi-quantitative analysis showed increased HAI scores （P<0.05） and increased inflammatory cell counts and area proportion （P<0.05）. In terms of molecular biological indicators， compared with the normal group， the mRNA and protein expression levels of TRPA1 and TPH1 in colon tissue decreased in the CC group （P<0.05， P<0.01）. ConclusionThe rhein-induced CC rat model conforms to the traditional Chinese medicine syndrome characteristics of Qi and Yin deficiency accompanied by Qi stagnation and blood stasis.

Functional constipation （FC） is a clinically common functional bowel disorder characterized by a protracted course and associations with various chronic disorders and psychological abnormalities. Although not life-threatening， FC significantly impairs patients' quality of life. FC subtypes include slow-transit constipation （STC）， defecatory disorder （DD）， and normal-transit constipation （NTC）. The pathological mechanisms underlying FC have not been fully elucidated， and overall clinical efficacy remains unsatisfactory. Animal models of FC serve as essential tools for the study of disease mechanisms and the development of novel therapeutics. This article systematically reviews the current state of research on the animal models of FC and identifies that rodents， particularly rats and mice， are the most commonly used species. Dogs and pigs are also employed in complex intervention studies due to their physiological similarities to humans， though their use is limited by housing challenges and ethical considerations. Induction methods vary across different FC subtypes. STC models are primarily established with chemical agents such as loperamide or compound diphenoxylate. DD modeling often involves low-fiber diets combined with methylene blue injection or rectal narrowing. NTC modeling mainly relies on low-fiber dietary interventions. In addition， disease-syndrome combination models based on traditional Chinese medicine （TCM） theory have been developed， encompassing excess patterns such as heat accumulation， cold accumulation， and Qi stagnation， as well as deficiency patterns including Qi deficiency， blood deficiency， Yin deficiency， and Yang deficiency. These are achieved through an approach of disease model + syndrome induction， enabling the integration of mechanisms from both Western and TCM perspectives. Models are evaluated from two aspects： disease and syndrome manifestations （e.g.， colonic transit， secretory function， and TCM syndrome indicators such as mental state and body weight） and disease mechanisms （e.g.， enteric nervous system， interstitial cells of Cajal， smooth muscle cells， gut microbiota， and metabolites）. However， current research still faces challenges such as poor consistency in some models， non-specific interference in mechanism interpretation， insufficient studies on NTC， and lack of TCM tongue and pulse diagnosis in evaluation. Future efforts should focus on optimizing model stability and specificity to provide a more reliable experimental basis for investigating the pathological mechanisms of FC and developing therapeutic agents.

Objective To investigate the impact of eccentric placement for various types of artificial aortic valves on downstream flow dynamics.Methods A physiological pulsatile circulation simulation system was employed and particle image velocimetry(PIV)was utilized to analyze the downstream flow field variations for bioprosthetic and mechanical valves under two placement conditions:centralized placement(0 mm)and eccentric placement(1 mm).Hemodynamic parameters such as velocity,vorticity,and viscous shear stress were assessed to evaluate the flow field characteristics.Results By analyzing the flow field variations at four characteristic time points,namely,early systole,acceleration phase,peak systole,and deceleration phase,a significant difference in flow field distribution between bioprosthetic and mechanical valves was observed.The bioprosthetic valve exhibited a centrally symmetric jet with a higher flow velocity,whereas the mechanical valve displayed a three-jet structure with a lower central flow velocity.Under eccentric placement,the blood flow in the aortic sinus region was sluggish,with a reduction in average velocity,hindering the formation and maintenance of vortices.During the peak systolic phase,the maximum viscous shear stresses in the sinus region for the bioprosthetic and mechanical valves were 0.45 and 0.67 Pa,respectively,approaching the threshold for endothelial cell damage.Conclusions Eccentric placement of both mechanical and bioprosthetic valves resulted in reduced sinus blood flow velocity and diminished viscous shear stress,creating favorable conditions for thrombus formation.In clinical practice,careful attention should be given to the placement of valve replacement to prevent eccentric placement.

In order to delve into the molecular mechanism underlying the increased pathogenicity of the recombinant Muscovy duck parvovirus(rMDPV)towards Muscovy ducklings,two sub-genom-ic fragments of the rMDPV strain ZW were cloned into the plasmid pBluescript Ⅱ(SK)to gener-ate the recombinant plasmid pZW.A single nucleotide mutation was engineered in the VP3 gene of pZW to discriminate from the parental strain ZW.pZW plasmid-lipid complex was transfected into the chorioallantoic membrane of 11-day-old embryonated Muscovy duck embryos,resulting in res-cue of infectious virus,rZW,carrying the genetic marker.The rescued virus was passaged in 12-day-old embryonated Muscovy duck embryos and exhibited the similar medium embryo lethal dose(ELD50)value and growth curve compared to the parental strain ZW.Both rZW and strain ZW led to 100％mortality in the infection tests performed with 3-day-old Muscovy duckling.Postmortem necropsy revealed a characteristic intestine embolism formed in the rZW-infected ducklings.Taken together,the generation of the infectious clone pZW lays a solid foundation for deciphering the pathogenesis of rMDPV.

In recent decades, the prevalence of hyperuricemia and gout has increased dramatically due to lifestyle changes. The drugs currently recommended for hyperuricemia are associated with adverse reactions that limit their clinical use. In this study, we report that berberine (BBR) is an effective drug candidate for the treatment of hyperuricemia, with its mechanism potentially involving the modulation of gut microbiota and its metabolite, succinic acid. BBR has demonstrated good therapeutic effects in both acute and chronic animal models of hyperuricemia. In a clinical trial, oral administration of BBR for 6 months reduced blood uric acid levels in 22 participants by modulating the gut microbiota, which led to an increase in the abundance of Bacteroides and a decrease in Clostridium sensu stricto_1. Furthermore, Bacteroides fragilis was transplanted into ICR mice, and the results showed that Bacteroides fragilis exerted a therapeutic effect on uric acid similar to that of BBR. Notably, succinic acid, a metabolite of Bacteroides, significantly reduced uric acid levels. Subsequent cell and animal experiments revealed that the intestinal metabolite, succinic acid, regulated the upstream uric acid synthesis pathway in the liver by inhibiting adenosine monophosphate deaminase 2 (AMPD2), an enzyme responsible for converting adenosine monophosphate (AMP) to inosine monophosphate (IMP). This inhibition resulted in a decrease in IMP levels and an increase in phosphate levels. The reduction in IMP led to a decreased downstream production of hypoxanthine, xanthine, and uric acid. BBR also demonstrated excellent renoprotective effects, improving nephropathy associated with hyperuricemia. In summary, BBR has the potential to be an effective treatment for hyperuricemia through the gut-liver axis.

Objective To investigate the impact of eccentric placement for various types of artificial aortic valves on downstream flow dynamics.Methods A physiological pulsatile circulation simulation system was employed and particle image velocimetry(PIV)was utilized to analyze the downstream flow field variations for bioprosthetic and mechanical valves under two placement conditions:centralized placement(0 mm)and eccentric placement(1 mm).Hemodynamic parameters such as velocity,vorticity,and viscous shear stress were assessed to evaluate the flow field characteristics.Results By analyzing the flow field variations at four characteristic time points,namely,early systole,acceleration phase,peak systole,and deceleration phase,a significant difference in flow field distribution between bioprosthetic and mechanical valves was observed.The bioprosthetic valve exhibited a centrally symmetric jet with a higher flow velocity,whereas the mechanical valve displayed a three-jet structure with a lower central flow velocity.Under eccentric placement,the blood flow in the aortic sinus region was sluggish,with a reduction in average velocity,hindering the formation and maintenance of vortices.During the peak systolic phase,the maximum viscous shear stresses in the sinus region for the bioprosthetic and mechanical valves were 0.45 and 0.67 Pa,respectively,approaching the threshold for endothelial cell damage.Conclusions Eccentric placement of both mechanical and bioprosthetic valves resulted in reduced sinus blood flow velocity and diminished viscous shear stress,creating favorable conditions for thrombus formation.In clinical practice,careful attention should be given to the placement of valve replacement to prevent eccentric placement.

In order to delve into the molecular mechanism underlying the increased pathogenicity of the recombinant Muscovy duck parvovirus(rMDPV)towards Muscovy ducklings,two sub-genom-ic fragments of the rMDPV strain ZW were cloned into the plasmid pBluescript Ⅱ(SK)to gener-ate the recombinant plasmid pZW.A single nucleotide mutation was engineered in the VP3 gene of pZW to discriminate from the parental strain ZW.pZW plasmid-lipid complex was transfected into the chorioallantoic membrane of 11-day-old embryonated Muscovy duck embryos,resulting in res-cue of infectious virus,rZW,carrying the genetic marker.The rescued virus was passaged in 12-day-old embryonated Muscovy duck embryos and exhibited the similar medium embryo lethal dose(ELD50)value and growth curve compared to the parental strain ZW.Both rZW and strain ZW led to 100％mortality in the infection tests performed with 3-day-old Muscovy duckling.Postmortem necropsy revealed a characteristic intestine embolism formed in the rZW-infected ducklings.Taken together,the generation of the infectious clone pZW lays a solid foundation for deciphering the pathogenesis of rMDPV.

Diarrhea-irritable bowel syndrome （IBS-D） is one of the common functional bowel diseases in clinical practice. Since it pathogenesis is complex and has not been fully elucidated， effective treatment methods remains to be developed for this disease. Establishing the animal models of IBS-D in accordance with the clinical characteristics of traditional Chinese medicine （TCM） and Western medicine helps to reveal the pathogenesis of this disease and improve the treatment plan. The fitting degree of an animal model with clinical characteristics is an indicator to evaluate the effectiveness of the animal model in simulating the disease characteristics of Western medicine and the syndromes of TCM based on the latest diagnostic standards. By reviewing the relevant articles about the animal models of IBS-D， we discovered that rats were the preferred animals for modeling， and the models were mainly induced by single factors， double factors， or the combination of multiple factors. The established animal models mainly present symptoms or signs associated with visceral hypersensitivity or/and gastrointestinal motility abnormalities. The single factor-induced rat models of IBS-D had high fitting degrees with the clinical characteristics of Western medicine but low fitting degrees with the TCM syndromes. The animal models induced by two or more factors had high but varied fitting degrees with the clinical characteristics of Western medicine. In addition， the animal models of IBS-D considering TCM syndromes mainly focuses on the syndrome of liver depression and spleen deficiency， and few models were established for the syndromes of spleen-kidney Yang deficiency， spleen-stomach dampness-heat， spleen deficiency and dampness excess， and cold and heat in complexity. Therefore， it is essential to improve the existing or develop new animal models of IBS-D in the future， so as to provide more tools for deciphering the mechanisms of TCM and Western medicine and developing treatment methods for this disease.