Objective To evaluate the safety and efficacy of a self-developed micro-normothermic machine perfusion (NMP) system (micro-perfusion device) for preserving isolated porcine limbs. Methods Five healthy Landrace pigs were selected, and their left and right forelimbs were randomly divided into the NMP group and static cold storage (SCS) group. The NMP group was perfused with the self-developed micro-perfusion device and polymerized hemoglobin perfusate for 32 hours at normothermia, while the SCS group was preserved at 4 ℃. Hemodynamic parameters such as perfusion pressure and flow were monitored. The pH value, partial pressure of oxygen (PO₂), lactic acid (Lac), creatine kinase (CK) and lactate dehydrogenase (LDH) in the perfusate were measured. Hematoxylin-eosin staining was used to assess the muscle tissue structure, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling was employed to evaluate muscle cell apoptosis, and immunohistochemistry staining was applied to detect the expressions of tumor necrosis factor (TNF)-α and interleukin (IL)-6. A mixed-effects model was used to analyze the effects of time and treatment methods on tissue structure, cell apoptosis and inflammatory factors. Results The device could stably maintain a perfusion pressure of (69±15) mmHg and a flow rate of (117±42) mL/min. The pH value and electrolytes of the perfusate were generally stable, with PO₂ maintained at a high level. Lac was maintained at 5.38(3.81, 6.45) mmol/L, while CK and LDH increased over time. After 32 hours of perfusion in the NMP group, both the myocyte spacing and apoptosis rate were better than those in the SCS group. Mixed-effects model analysis showed that there were statistically significant differences in the effects of NMP treatment and SCS treatment on myocyte spacing and apoptosis rate per unit time (both P < 0.05). There were no statistically significant differences in TNF-α and IL-6 between the two groups, and mixed-effects model analysis showed no statistically significant differences in the effects of NMP treatment and SCS treatment on TNF-α and IL-6 per unit time (both P > 0.05). Conclusions The micro-perfusion device used in this study may achieve 32-hour normothermic preservation in a porcine limb amputation model, maintain basic metabolism and ionic homeostasis, reduce muscle structural damage and cell apoptosis without inducing additional inflammatory responses. This technology is expected to significantly extend the time window for replantation of amputated limbs in disaster rescue and long-distance transportation, providing an important technical basis for clinical translation and subsequent replantation research.

Objective To explore the dynamic changes of gut microbiota metabolites in septic patients following admission, as well as the correlations between these metabolites, the gut microbiota, and the prognosis of septic patients. Methods A total of 119 fecal samples were collected from 23 septic patients, 16 non-septic patients admitted to the Emergency Intensive Care Unit (ICU), and 20 healthy controls at Zhongshan Hospital, Fudan University, from January to August 2019. The 16S rRNA gene sequencing technology was applied to analyze the microbiome, while ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used for metabolomics research. The R software was used to analyze the gut microbiota and metabolite data. Based on 180-day survival status after admission, the sepsis group was divided into the survival group (n＝15) and the death group (n＝8) to analyze differential metabolites between the two groups. Spearman correlation coefficients were used to assess correlations between gut microbiota and metabolites. Results In the first week of ICU stay, gut microbiota metabolites such as nicotinic acid, methylsuccinic acid, and glutaric acid were significantly lower in septic patients than in healthy controls (P＜0.05), whereas tryptophan, histidine, valine, and pyroglutamic acid were higher in septic patients (P＜0.05). The methylsuccinic acid and phenylacetic acid levels in the first week were lower in the death group than those in the survival group (P＜0.05), and the levels of methylsuccinic acid, phenylacetic acid, and glutaric acid were lower in the third week (P＜0.05). Further analysis indicated that methylsuccinic acid was closely associated with sepsis prognosis. These differential metabolites involved in metabolic pathways such as phenylalanine metabolism and β-alanine metabolism. Most differential amino acids were positively correlated with opportunistic pathogens but negatively correlated with normal gut microbiota. Conversely, metabolites such as nicotinic acid, phenylacetic acid, methylsuccinic acid, and glutaric acid were negatively correlated with opportunistic pathogens and positively correlated with normal gut microbiota. Conclusions Significant dynamic changes occur in gut microbiota metabolites in septic patients, with methylsuccinic acid, phenylacetic acid, and glutaric acid potentially playing important roles in determining patient prognosis.

BACKGROUND: Temozolomide (TMZ) resistance is a significant challenge in treating glioblastoma (GBM). Collagen remodeling has been shown to be a critical factor for therapy resistance in other cancers. This study aimed to investigate the mechanism of TMZ chemoresistance by GBM cells reprogramming collagens. METHODS: Key extracellular matrix components, including collagens, were examined in paired primary and recurrent GBM samples as well as in TMZ-treated spontaneous and grafted GBM murine models. Human GBM cell lines (U251, TS667) and mouse primary GBM cells were used for in vitro studies. RNA-sequencing analysis, chromatin immunoprecipitation, immunoprecipitation-mass spectrometry, and co-immunoprecipitation assays were conducted to explore the mechanisms involved in collagen accumulation. A series of in vitro and in vivo experiments were designed to assess the role of the collagen regulators prolyl 4-hydroxylase subunit alpha 1 (P4HA1) and yes-associated protein (YAP) in sensitizing GBM cells to TMZ. RESULTS: This study revealed that TMZ exposure significantly elevated collagen type I (COL I) expression in both GBM patients and murine models. Collagen accumulation sustained GBM cell survival under TMZ-induced stress, contributing to enhanced TMZ resistance. Mechanistically, P4HA1 directly binded to and hydroxylated YAP, preventing ubiquitination-mediated YAP degradation. Stabilized YAP robustly drove collagen type I alpha 1 ( COL1A1) transcription, leading to increased collagen deposition. Disruption of the P4HA1-YAP axis effectively reduced COL I deposition, sensitized GBM cells to TMZ, and significantly improved mouse survival. CONCLUSION P4HA1 maintained YAP-mediated COL1A1 transcription, leading to collagen accumulation and promoting chemoresistance in GBM.
Temozolomide ; Humans ; Glioblastoma/drug therapy* ; Animals ; Mice ; Cell Line, Tumor ; Drug Resistance, Neoplasm/genetics* ; YAP-Signaling Proteins ; Hydroxylation ; Dacarbazine/pharmacology* ; Adaptor Proteins, Signal Transducing/metabolism* ; Transcription Factors/metabolism* ; Collagen/biosynthesis* ; Collagen Type I/metabolism* ; Prolyl Hydroxylases/metabolism* ; Antineoplastic Agents, Alkylating/therapeutic use*

OBJECTIVE: To prepare decellularized nerve grafts from alpha-1, 3-galactosyltransferase (GGTA1) gene-edited pigs and explore their biocompatibility for xenotransplantation. METHODS: The sciatic nerves from wild-type pigs and GGTA1 gene-edited pigs were obtained and underwent decellularization. The alpha-galactosidase (α-gal) content in the sciatic nerves of GGTA1 gene-edited pigs was detected by using IB4 fluorescence staining and ELISA method to verify the knockout status of the GGTA1 gene, and using human sciatic nerve as a control. HE staining and scanning electron microscopy observation were used to observe the structure of the nerve samples. Immunofluorescence staining and DNA content determination were used to evaluate the degree of decellularization of the nerve samples. Fourteen nude mice were taken, and subcutaneous capsules were prepared on both sides of the spine. Decellularized nerve samples of wild-type pigs ( n=7) and GGTA1 gene-edited pigs ( n=7) were randomly implanted in the subcutaneous capsules. Blood was drawn at 1, 3, 5, and 7 days after implantation to detect neutrophil counting. RESULTS: IB4 fluorescence staining and ELISA detection showed that GGTA1 gene was successfully knocked out in the nerves of GGTA1 gene-edited pigs. HE staining showed that the structure of the decellularized nerve from GGTA1 gene-edited pigs was well preserved; the nerve basement membrane tube structure was visible under scanning electron microscopy; no cell nuclei was observed, and the extracellular matrix components was retained in the nerve grafts by immunofluorescence staining; and the DNA content was significantly reduced when compared with the normal nerves ( P<0.05). In vivo experiments showed that the number of neutrophils in the two groups were similar at 1, 3, and 7 days after implantation, with no significant difference ( P>0.05); only at 5 days, the number of neutrophils was significantly lower in the GGTA1 gene-edited pigs than in the wild-type pigs ( P<0.05). CONCLUSION The decellularized nerve grafts from GGTA1 gene-edited pigs have well-preserved nerve structure, complete decellularization, retain the natural nerve basement membrane tube structure and components, and low immune response after xenotransplantation through in vitro experiments.
Animals ; Transplantation, Heterologous ; Galactosyltransferases/genetics* ; Sciatic Nerve/immunology* ; Swine ; Tissue Engineering/methods* ; Humans ; Graft Rejection/prevention & control* ; Gene Editing ; Mice ; Mice, Nude ; Heterografts/immunology* ; Animals, Genetically Modified ; Tissue Scaffolds ; Decellularized Extracellular Matrix

Glioma represents the most prevalent malignant tumor of the central nervous system, with chemotherapy serving as an essential adjunctive treatment. However, most chemotherapeutic agents exhibit limited ability to penetrate the blood-brain barrier (BBB). This study introduced a novel dual-targeting strategy for glioma therapy by modulating the formation of nanobody-driven protein coronas to enhance the brain and tumor-targeting efficiency of hydrophobic cisplatin prodrug-loaded lipid nanoparticles (C8Pt-Ls). Specifically, nanobodies (Nbs) with fibrinogen-binding capabilities were conjugated to the surface of C8Pt-Ls, resulting in the generation of Nb-C8Pt-Ls. Within the bloodstream, Nb-C8Pt-Ls could bound more fibrinogen, forming the protein corona that specifically interacted with LRP-1, a receptor highly expressed on the BBB. This interaction enabled a "Hitchhiking Effect" mechanism, facilitating efficient trans-BBB transport and promoting effective brain targeting. Additionally, the protein corona interacted with LRP-1, which is also overexpressed in glioma cells, achieving precise tumor targeting. Computational simulations and SPR detection clarified the molecular interaction mechanism of the Nb-fibrinogen-(LRP-1) complex, confirming its binding specificity and stability. Our results demonstrated that this strategy significantly enhanced C8Pt accumulation in brain tissues and tumors, induced apoptosis in glioma cells, and improved therapeutic efficacy. This study provides a novel framework for glioma therapy and underscores the potential of protein corona modulation-based dual-targeting strategies in advancing treatments for brain tumors.

Cardiac fibrosis is characterized by an elevated amount of extracellular matrix (ECM) within the heart. However, the persistence of cardiac fibrosis ultimately diminishes contractility and precipitates cardiac dysfunction. Circular RNAs (circRNAs) are emerging as important regulators of cardiac fibrosis. Here, we elucidate the functional role of a specific circular RNA CELF1 in cardiac fibrosis and delineate a novel feedback loop mechanism. Functionally, circ-CELF1 was involved in enhancing fibrosis-related markers' expression and promoting the proliferation of cardiac fibroblasts (CFs), thereby exacerbating cardiac fibrosis. Mechanistically, circ-CELF1 reduced the ubiquitination-degradation rate of BRPF3, leading to an elevation of BRPF3 protein levels. Additionally, BRPF3 acted as a modular scaffold for the recruitment of histone acetyltransferase KAT7 to facilitate the induction of H3K14 acetylation within the promoters of the Celf1 gene. Thus, the transcription of Celf1 was dramatically activated, thereby inhibiting the subsequent response of their downstream target gene Smad7 expression to promote cardiac fibrosis. Moreover, Celf1 further promoted Celf1 pre-mRNA transcription and back-splicing, thereby establishing a feedback loop for circ-CELF1 production. Consequently, a novel feedback loop involving CELF1/circ-CELF1/BRPF3/KAT7 was established, suggesting that circ-CELF1 may serve as a potential novel therapeutic target for cardiac fibrosis.

Objective:To compare the protective effects of the static cold storage (SCS) and normothermic machine perfusion (NMP) on the skeletal muscle of the amputated limbs of pigs.Methods:Four Landrace pigs were selected, from which eight limbs were amputated and divided into SCS group ( n=5) and NMP group ( n=3) according to the random number table method. After blood collection from the carotid artery, an amputated limb model was established by amputating the limbs at the scapulohumeral joints. The limbs in the SCS group were wrapped in sterile cloth and stored at 4 ℃ for 24 hours. In the NMP group, the limbs were mechanically perfused with a red blood cell-containing perfusion fluid at 37 ℃ for 24 hours, with 70% of the perfusion fluid replaced every 6 hours. Before the experiment, cross-matching tests with the saline medium were conducted between donor and recipient pigs to evaluate blood coagulation and blood safety in the NMP group. An allogeneic red blood cell perfusion fluid was prepared and the levels of pH, Na +, K +, Cl -, Ca 2+, glucose (Glu), hematocrit (Hct), lactic acid (Lac) and osmotic pressure of the perfusion fluid were measured. At 0, 6, 12, 18, and 24 hours after perfusion, the skin temperature and oxyhemoglobin saturation (SaO 2) levels in the NMP group were monitored and the levels of pH, Glu, creatine kinase (Ck), K +, Ca 2+, and Na +levels of the perfusion fluid were analyzed to evaluate the metabolism of the skeletal muscle in the amputated limbs. The mean intercellular distance and apoptosis index of the myocytes were quantitatively analyzed and histopathological changes were observed by performing HE staining and TUNEL staining on the skeletal muscle of the amputated limbs in both groups at 0 and 24 hours after perfusion. After perfusion was ended, the weight gain rate and swelling degree of the amputated limbs were compared between the two groups and the overall state of the amputated limbs was evaluated. Results:The result of the cross-matching test between donor and recipient pig blood was negative. The parameters in the prepared red blood cell-containing perfusion fluid generally maintained within a normal range: pH 7.38±0.04, Na + concentration (138.30±4.48)mmol/L, K + concentration (3.50±0.26)mmol/L, Glu concentration (6.11±2.08)mmol/L, and osmotic pressure (305.67±3.79)mmol/L. However, slightly higher Cl - and Ca 2+ concentrations [(118.34±12.00)mmol/L and (2.00±0.15)mmol/L] and lower Hct and lactate concentrations [0.30±0.03 and (1.54±0.38)mmol/L] were detected when compared with the reference range. During the perfusion, the average skin temperature of the amputated limbs in the NMP group was (36.13±0.98)℃, with the skin temperatures at 6, 12, 18, and 24 hours after perfusion being significantly higher than that at 0 hour ( P<0.01), while no significant difference among the skin temperatures at 6, 12, 18, and 24 hours after perfusion was observed ( P>0.05). The SaO 2 levels in the skin of the amputated limbs in the NMP group averaged over 95%, which showed no significant difference at 0, 12, 18, and 24 hours after perfusion ( P>0.05), while a significant elevation was observed at 6 hours compared with that at 0 hour ( P<0.05). There were no significant differences in pH, Glu, Na +, and Ca 2+ levels in the NMP group at 0, 6, 12, 18, and 24 hours after perfusion ( P>0.05), while the Ck levels at 18 and 24 hours were both significantly higher than that at 6 hours after perfusion ( P<0.05), and the Ck levels at 6, 12, 18, and 24 hours were all significantly higher than that at 0 hour ( P<0.05). The K + level progressively increased with the perfusion time, with significant elevations at 18 and 24 hours after perfusion compared with that at 0 hour ( P<0.05). HE staining revealed well-preserved muscle fiber continuity and regular arrangement in the NMP group and the SCS group at 0 hour, with an intercellular distance of (8.95±0.60)μm. At 24 hours, the NMP group exhibited slight skeletal muscle fiber rupture and swelling, with a slightly increased intercellular distance of (14.75±0.90)μm, significantly greater than that at 0 hour ( P<0.01). At 24 hours, the SCS group showed marked skeletal muscle fiber rupture and swelling, with a significantly increased intercellular distance of (23.51±1.49)μm, significantly larger than those at 0 hour in the same group and at 24 hours in the NMP group ( P<0.01). TUNEL immunofluorescence staining indicated a tiny amount of apoptotic cells in the skeletal muscle in both groups at 0 hour, with an apoptotic index of (4.26±1.62)%. There was a small number of apoptotic cells in the skeletal muscle in the NMP group at 24 hours, with an apoptotic index of (25.94±2.69)%, significantly larger than that in the same group at 0 hour ( P<0.01). The SCS group exhibited a large number of apoptotic cells at 24 hours, with an apoptotic index of (62.97±3.22)%, significantly larger than those at 0 hour in the same group and at 24 hours in the NMP group ( P<0.01). In comparison with the SCS group at 24 hours, the amputated limbs in the NMP group showed red color in the appearance, no symptoms of ischemic muscle contracture and good joint movement despite slight edema in the subcutaneous layer. At 24 hours, the weight gain rate of the amputated limbs was (15.82±0.89)% in the NMP group, significantly higher than (0.97±0.28)% in the SCS group ( P<0.01). Conclusion:Compared with SCS, NMP with the red blood cell-containing perfusion fluid prepared with the allogeneic blood for the amputated limbs of pigs can alleviate the ischemic injury of the muscle fibers and inhibit the apoptosis of the muscle cells by sustaining stable energy and oxygen supply and balancing ion homeostasis and pH of the perfusion fluid.

Objective:To investigate the neuroprotective effects of ginsenoside Rb1 in neonatal mice with Hypoxic Ischemia(HI)and analyze its potential molecular mechanisms.Methods:Seven-day-old C57BL/6 neonatal mice were randomly assigned to three groups:Sham group,hypoxic-ischemic(HI)model group,and HI model+ginsenoside Rb1 intervention group(HI+Rb1),with 10 mice per group.The modified Rice-Vannucci method was used to establish the HI model,and ginsenoside Rb1(20 mg/kg)was administered via intraperitoneal injection for 7 consecutive days post-surgery(once per day).Brain damage was assessed on days 7 and 14 post-surgery by evaluating cortical neurons and glial cell numbers,as well as the activation status of the ERK signaling pathway.Additionally,in utero electroporation(IUE)was used to overexpress the ERK signaling pathway in the cortical neurons,and the impact of ERK activation on glial cell development was observed.Further,IUE was used to overexpress ERK in the cortex of P0 neonatal mice,fol-lowed by the HI model on day 7 to analyze the effects of enhanced ERK signaling on oligodendrocyte development and myelin regeneration.Results:Compared to the HI group,the HI+Rb1 intervention group showed significant improve-ment in motor ability,reduction in brain injury area,less mature neuron loss,and increased newborn neurons.Addi-tionally,the number of oligodendrocytes in the cortex was increased,and the activation of the ERK signaling pathway was enhanced.In mice with overexpression of the ERK signaling pathway in the cortex,there was a significant increase in oligodendrocytes.In the HI model with ERK overexpression,an increased number of oligodendrocyte precursor cells were found around the brain injury area,consistent with the results of ginsenoside Rb1 intervention.Conclusion:Gin-senoside Rb1 exerts neuroprotective effects in neonatal mice with hypoxic-ischemic brain injury,potentially through the enhancement of ERK signaling,promoting oligodendrocyte proliferation and myelin regeneration.

Objective To explore the protective effects of genetically modified porcine erythrocyte suspension as a subnormothermic normoxic mechanical perfusate on hypoxic-ischemic brain injury in cynomolgus monkeys caused by traumatic hemorrhage.Methods Cynomolgus monkeys were randomly divided into positive and negative control groups(a total of 3 monkeys,with 3 left cerebral hemispheres as the positive control group and 3 right cerebral hemispheres as the negative control group)and the subnormothermic perfusion group(n=3).The positive control group was directly sampled 1 hour after circulatory arrest,while the negative control group was placed at subnormothermic conditions for 6 hours after circulatory arrest.The subnormothermic perfusion group underwent 6 hours of subnormothermic normoxic mechanical perfusion of the bilateral common carotid arteries of the cynomolgus monkey hypoxic-ischemic brain injury model using genetically modified porcine erythrocyte suspension 1 hour after circulatory arrest.Before perfusion,cross-matching experiments were conducted between the six genetically modified pig and the cynomolgus monkeys.After the start of perfusion,the levels of routine blood indicators in the perfusate were detected at 0,1,2,3,4,5 and 6 hours.Blood oxygen saturation was recorded,and the levels of Na+,K+,Ca2+,glucose and blood pH in the perfusate were measured,as well as the levels of IgG and IgM in the perfusate.After 6 hours of perfusion,the water content of the brain tissue was measured.Nissl staining was performed on the frontal cortex and hippocampal regions,and immunofluorescence staining was used to detect the expression of glial fibrillary acidic protein(GFAP),ionized calcium-binding adapter molecule 1(Iba1)and neuronal nuclear antigen(NEUN).Results The cross-matching results between the six genetically modified pig and the cynomolgus monkeys were negative.The number of red blood cells in the perfusate decreased significantly at 3 hours of perfusion,and the hemoglobin level showed a downward trend at 1,3,5 and 6 hours.The number of white blood cells and platelets decreased at all time points.The blood oxygen saturation in the subnormothermic perfusion group remained stable at 95%-98%,and the levels of blood oxygen saturation,Na+,Ca2+,glucose and pH were stable,while the K+level first increased and then decreased.There was no significant difference in the levels of IgG and IgM before and after perfusion.The water content of brain tissue at the end of perfusion in the subnormothermic perfusion group was significantly higher than that in the positive control group(P<0.001).Nissl staining results showed that compared with the positive control group,the pyramidal neurons in the prefrontal cortex of the subnormothermic perfusion group maintained better morphological integrity,with no significant increase in enlarged and deformed cells.In the hippocampal CA1 region,there was a slight increase in enlarged and deformed cells,and a few cells with undamaged structures showed reduced cell size.In the hippocampal dentate gyrus,fewer granule neurons had compromised structural integrity,with increased cell edema.NEUN immunofluorescence staining showed that compared with the positive control group,the pyramidal neurons in the prefrontal cortex and hippocampal CA1 region of the subnormothermic perfusion group had better morphological states,with clear axons.The granule cells in the hippocampal dentate gyrus were well preserved,but the nuclei were less well protected.GFAP immunofluorescence staining showed that compared with the positive control group,the subnormothermic perfusion group had sparser protrusions that were more tightly associated with neurons.Iba1 immunofluorescence staining showed that compared with the positive control group,the subnormothermic perfusion group had thicker and fewer protrusions.Conclusions Compared with the positive control group,subnormothermic normoxic mechanical perfusion with genetically modified porcine erythrocyte perfusate increases brain tissue edema in cynomolgus monkeys,but better preserves the morphological integrity of neurons and glial cells.The protective effects may be related to the continuous oxygen and energy supply,maintenance of ion homeostasis and perfusate pH,reduced rejection,and low metabolic state of the whole brain.

Objective:To explore the effects of medication interval on the quality of split-dose bowel preparation and analyze the independent risk factors affecting the quality of bowel preparation.Methods:This pilot study involved two centers. Adult outpatients who underwent screening, surveillance, and diagnostic colonoscopy in the First Affiliated Hospital of Naval Medical University ( n=46) and the Fifth Hospital of Zhangjiakou ( n=20) between April and June 2023 were enrolled. Bowel preparation was conducted based on the guideline. Patients were divided into the short-interval group (4-<10 hours, n=45) and the long-interval group (10-16 hours, n=21) based on the time between the two administrations of polyethylene glycol during bowel preparation. Differences in terms of patient-reported outcome measurements (patient-reported willingness to repeat the bowel preparation regimen, satisfaction with bowel preparation, satisfaction with sleep), defecation frequency, Boston bowel preparation scale scores, bowel preparation bubble scores, bowel preparation qualified rates, polyp detection rates and incidence of adverse events were compared. Relevant factors influencing bowel preparation quality were analyzed by univariate logistic regression. Results:There were no significant differences in patient-reported willingness to repeat the bowel preparation regimen [88.9% (40/45) VS 85.7% (18/21), χ2<0.001, P>0.999], the satisfaction with bowel preparation [65.9% (29/45) VS 57.1% (12/21), χ2=0.469, P=0.493], or the satisfaction with sleep quality [35.6% (16/45) VS 28.6% (6/21), χ2=0.314, P=0.575] between the short-interval and long-interval groups. Similarly, no significant differences were observed between the groups in defecation frequency (11.3±4.8 VS 10.2±4.4, t=0.861, P=0.395), Boston bowel preparation scale scores (8.2±1.4 scores VS 7.9±1.2 scores, t=1.024, P=0.311), bowel preparation bubble scores (8.6±1.0 scores VS 8.4±1.5 scores, t=0.672, P=0.506), bowel preparation qualified rates [88.9% (40/45) VS 90.5% (19/21), χ2<0.001, P>0.999], polyp detection rates [33.3% (15/45) VS 47.6% (10/21), χ2=1.242, P=0.265], or incidence of adverse events [24.4% (11/45) VS 14.3% (3/21), χ2=0.381, P=0.537]. Univariate logistic analysis suggested that a low-fiber diet ( OR=8.100, 95% CI:1.400-46.849, P=0.019) was an influencing factor for qualified bowel preparation. Conclusion:Medication interval of the two doses of polyethylene glycol in a split-dose bowel preparation regimen for colonoscopy has no significant impact on bowel preparation quality. Notably, preoperative low-fiber diet emerges as an independent protective factor for qualified bowel preparation.