Objective To investigate the effects of aerobic exercise and different exercise habits on skeletal muscle function and the possible molecular mechanisms in colorectal cancer-loaded mice.Methods Thirty-five 5-week-old BABL/c male mice were acclimatized to feeding for 1 week and then divided randomly into the following groups:control(D),tumor(M),exercise preconditioning(QAM),lifetime exercise(AM),and exercise(HAM)groups(n=7 mice per group).Mice in the QAM and AM groups underwent aerobic exercise regimen 1 from weeks 2～6.At week 7,mice in the experimental groups received 0.2 mL of CT26 colon cancer cell suspension subcutaneously in the dorsal aspect of the left hind limb,while control mice received 0.2 mL of saline at the corresponding site.Mice in the AM and HAM groups were subjected to aerobic exercise regimen 2 for weeks 7～9.The general status and skeletal muscle mass and function were monitored in all mice throughout the experiments.After completion of the experiment,samples were collected and the cross-sectional area of gastrocnemius muscle fibers(CSA)was measured by hematoxylin and eosin staining and expression levels of proteins related to synthesis and catabolism of the gastrocnemius muscle were analyzed by Western Blot.Results(1)The weight ratio of the gastrocnemius muscle was significantly lower in mice in the M,QAM,and HAM groups compared with group D,and was significantly higher in AM mice compared with M,QAM,and HAM mice.(2)Grip strength,endurance,skeletal muscle circumference,and CSA were significantly lower in group D mice compared with the other groups,and was most enhanced in group HAM.Endurance and CSA were consistently enhanced in groups QAM,AM,and HAM.(3)Muscle RING-finger protein-1(MuRF1)expression levels were significantly lower in groups M,QAM,AM,and HAM than in group D,significantly lower in groups AM and HAM than in group M,and significantly lower in group HAM than in group QAM.(4)Fibronectin type Ⅲ domain-containing protein 5(FNDC5)expression levels were significantly lower in group M than in groups D and QAM.(5)Peroxisome proliferator-activated receptor gamma coactivator 1-alpha expression levels were significantly lower in the QAM and HAM groups compared with group M.(6)Expression levels of phospho(p)-AMP-activated protein kinase(AMPK)/AMPK and p-AMPK were significantly higher in group QAM than in groups D and M,p-AMPK expression significantly lower in groups AM and HAM was than in group QAM,and AMPK expression was significantly lower in groups QAM,AM,and HAM than in group D.Conclusions Exercise preconditioning and continuous aerobic exercise can improve skeletal muscle mass and function in CT26 colon cancer-loaded mice by activating AMPK phosphorylation to stimulate skeletal muscle secretion of FNDC5,thereby regulating the expression of MuRF1 protein.

Objective:To evaluate the effects of two dressing methods on wound healing and patient satisfaction after cosmetic suturing for pediatric facial trauma.Methods:A prospective randomized controlled trial was conducted at Dongying People′s Hospital from October 2022 to October 2023. A total of 180 pediatric patients [105 males, 75 females, aged 3-7 (3.9±1.4) years] with facial trauma requiring cosmetic suturing were enrolled in this study. Participants were randomly divided into the study group ( n=91) and control group ( n=89) using a random number table. During the first postoperative dressing change at 24 hours, the study group received saline cleaning followed by erythromycin ointment coverage, while the control group underwent iodine disinfection with gauze coverage. Pain intensity during the second dressing change was assessed using the Chinese version of the Children′s Hospital of Eastern Ontario pain scale (CHEOPS). Wound healing at 6-7 days post-suturing was evaluated using the Chinese version of the redness, edema, ecchymosis, discharge, and approximation (REEDA) scale. Scar appearance at 14 days was measured via the Stony Brook scar evaluation scale (SBSES). Complication rates (infection, dehiscence) and satisfaction rates were statistically analyzed. Results:During the second dressing change, the CHEOPS score was significantly lower in the study group (6.27±1.32) than that in the control group (6.89±1.21) ( P=0.001). At 6-7 days, the REEDA score in the study group (2.26±1.91) was significantly lower than that in the control group (3.07±2.13) ( P=0.008). At 14 days, the SBSES score was significantly lower in the study group [2.60±1.42) vs (3.89±1.50), P<0.001]. The infection rate was 1.09% (1/91) in the study group and 1.12% (1/89) in the control group, with two cases of epidermal dehiscence observed in the control group. The satisfaction rate in the study group was 93.41% (85/91), which was higher than that in the control group [85.49% (76/89), P=0.020]. Conclusion:Saline cleaning combined with erythromycin ointment coverage reduces pain during wound dressing change, facilitates early wound healing, and improves patient′s satisfaction.

Objective To investigate the effect of aerobic exercise preconditioning on cardiac function in mice bearing subcutaneous transplantable tumors and explore the potential molecular mechanisms.Methods Twenty-four 6-week-old male BALB/c mice were selected.After an acclimation period,they were randomly assigned to a control group(C),a tumor group(M)and an exercise-preconditioning plus tumor group(EM),each of eight.The EM group underwent a 4-week aerobic exercise interven-tion.Meanwhile,the C group received 0.2 ml of physiological saline injected subcutaneously on the dorsum of the proximal left hind limb,while the M and EM groups were inoculated at the same site with 0.2 ml of a CT26.WT colon carcinoma cell suspension.Three weeks after inoculation,cardiac function was assessed by transthoracic echocardiography.Hearts were then harvested for hematoxylin-eo-sin staining to evaluate cardiomyocyte cross-sectional area(CSA),while Western blot was performed to determine the expression of proteins related to myocardial protein synthesis and degradation.Results(1)Compared with group C,group M exhibited significantly lower body weight and heart weight(P<0.05),and reduced left ventricular ejection fraction(LVEF),fractional shortening(FS)and stroke vol-ume(SV)(P<0.05),as well as cardiomyocyte CSA(P<0.01)and total mTOR(P<0.01),phosphory-lated mTOR(p-mTOR)(P<0.01)and the p-mTOR/mTOR ratio(P<0.05),but a significant increase in the expression of the muscle ring finger 1(MuRF-1)and the muscle atrophy F-box(MAFbx/Atrog-in-1)(P<0.01 and P<0.05,respectively).(2)Compared with group M,group EM showed significant-ly greater heart weight(P<0.05);increased left ventricular posterior wall thickness at end-diastole(LVPWd),LVEF,FS and SV(P<0.05),as well as the larger cardiomyocyte CSA and total mTOR,p-mTOR and the p-mTOR/mTOR ratio(P<0.05),but reduced MuRF-1 and Atrogin-1 expression(P<0.05).Conclusion Four weeks of aerobic exercise preconditioning ameliorated myocardial atrophy and improved systolic cardiac function in mice bearing subcutaneously transplanted CT26 tumors.Such beneficial effects may be associated with exercise-induced down regulation of the protein degradation mediators MuRF-1 and Atrogin-1 and up regulation of total mTOR and p-mTOR.

Objective To explore the effect of aerobic exercise on sarcopenia in CT26 tumor mice through the gut microbiota-skeletal muscle axis and its potential mechanism.Methods Forty-eight SPF BALB/c male mice aged 8 weeks were randomly divided into a normal control group(group NC,n=12),a normal control+aerobic exercise group(group NA,n=12),a CT26 tumor-associated sarco-penia group(group TS,n=12)and a CT26 tumor-associated sarcopenia+aerobic exercise group(group TSA,n=12).After a 2-week adaptive exercise period,CT26 cell suspension(0.2 mL,1×107 cells/mL)was subcutaneously injected into the dorsal region of mice in group TS and group TSA,while group NC and group NA were inoculated with 0.2 mL normal saline.One day later,group NA and group TSA underwent a 4-week aerobic treadmill running intervention(14 m/min,60 min/day,6 days/week).If a mouse failed to complete the target intensity on a given day,its running speed was reduced by 20%the following day.Moreover,group NA and group TSA received no exercise interven-tion.General health status of all groups was monitored throughout the study.The forelimb gripping force,rotarod walking time and the cross-sectional area of gastrocnemius muscle fibers were measured.Moreover,the ultrastructural changes of gastrocnemius were observed by transmission electron micro-scope,while the cecum contents were observed by 16S rRNA sequencing.Meanwhile,the pathological morphological changes of small intestine wall were observed using HE,while the contents of tumor ne-crosis factor-α(TNF-α),interleukin-6(IL-6),interleukin-1β(IL-1β)and lipopoly saccharide(LPS)of serum and gastrocnemius muscle were determined by using ELISA.Moreover,small intestine zonula occludens-1(ZO-1),Occludin and muscle ring finger 1(MuRF1),muscle atrophy F-box(MAF-bx),Toll-like receptor 4(TLR4)/myeloid differentiation factor 8(MyD88)/nuclear transcription factor-κB(NF-κB)signal pathway related proteins expression levels of gastrocnemius muscle,as well as muscle ring finger 1(MuRF1)and muscle atrophy F-box(MAF-bx)were detected using Western blot.Results(1)Subcutaneous tumors were prominent in group TS.The forelimb gripforce,wet weight and cross-sectional area of gastrocnemius,and rotarod walking time in group TS at the 5th and 6th weekends were significantly lower than group NC(P<0.01),while the relative expression levels of MuRF1 and MAF-bx proteins in the gastrocnemius muscle in group TS were significantly higher than the latter group(P<0.05,P<0.01).Moreover,transmission electron microscopy revealed sparse and dis-organized muscle fiber arrangement in group TS,with visible Z-lines but indistinct M-lines,as well as shortened,poorly defined,and thin sarcomeres.(2)The group TSA exhibited significantly higher α-diversity indices(Shannon,Chao1,and Observed species)in gut microbiota compared to group TS(P<0.05,P<0.01,P<0.05),while the β-diversity differed to some extent between the two groups.At phylum level,the F/B ratio was lower in group NA than that group NC,with that of group TSA low-er than group TS.At genus level,the relative abundances of Muribaculaceae,Bacteroides,Roseburia,and Alistipes in group NA were higher than group NC,and those of Alloprevotellaand Helicobacter were significantly lower,while those of Muribaculaceae,Lachnospiraceae_NK4A136_group,Roseburia,Bacteroides,Lachnospiraceae_UCG-001 of group TSA were significantly higher than group TS.Nota-bly,Roseburia and Alistipes were the most significantly enriched genera in group TSA and group TS(LDA score>4 for both).(3)The inflammatory cells of the small intestine wall in group TSA signifi-cantly reduced than those in group TS(P<0.05).Moreover,the expression level of ZO-1 proteins in the small intestine wall were significantly higher in group NA than group NC,and that of ZO-1 and Occludin proteins in the small intestine wall was significantly higher in group TSA than those in group TS(P<0.05).(4)The group NA exhibited significantly lower LPS concentrations in the gastrocne-mius muscle compared to group NC(P<0.05).Similarly,the group TSA showed reduced LPS levels in both serum and gastrocnemius compared to group TS(P<0.05).The relative protein expression of p-IκBα and p-NF-κB p65 significantly decreased in group TSA compared to group TS(P<0.05).The group TS displayed elevated concentrations of pro-inflammatory cytokines(TNF-α,IL-1β)in serum and gastrocnemius compared to group NC(P<0.01,P<0.05).The group TSA demonstrated significantly lower levels of TNF-α and IL-6 in these tissues in comparison with group TS(P<0.05,P<0.01).Conclusion Aerobic exercise can improve gut microbiota α diversity,adjusting its composition,improv-ing intestinal mucosal barrier function,reducing the LPS-induced pro-inflammatory response,and delay-ing skeletal muscle atrophy.The underlying mechanism may involve down regulation of TLR4/MyD88/NF-κB signaling in skeletal muscle,which has a positive effect on Gut-Muscle Axis.

Objective To investigate the effect of aerobic exercise preconditioning on cardiac function in mice bearing subcutaneous transplantable tumors and explore the potential molecular mechanisms.Methods Twenty-four 6-week-old male BALB/c mice were selected.After an acclimation period,they were randomly assigned to a control group(C),a tumor group(M)and an exercise-preconditioning plus tumor group(EM),each of eight.The EM group underwent a 4-week aerobic exercise interven-tion.Meanwhile,the C group received 0.2 ml of physiological saline injected subcutaneously on the dorsum of the proximal left hind limb,while the M and EM groups were inoculated at the same site with 0.2 ml of a CT26.WT colon carcinoma cell suspension.Three weeks after inoculation,cardiac function was assessed by transthoracic echocardiography.Hearts were then harvested for hematoxylin-eo-sin staining to evaluate cardiomyocyte cross-sectional area(CSA),while Western blot was performed to determine the expression of proteins related to myocardial protein synthesis and degradation.Results(1)Compared with group C,group M exhibited significantly lower body weight and heart weight(P<0.05),and reduced left ventricular ejection fraction(LVEF),fractional shortening(FS)and stroke vol-ume(SV)(P<0.05),as well as cardiomyocyte CSA(P<0.01)and total mTOR(P<0.01),phosphory-lated mTOR(p-mTOR)(P<0.01)and the p-mTOR/mTOR ratio(P<0.05),but a significant increase in the expression of the muscle ring finger 1(MuRF-1)and the muscle atrophy F-box(MAFbx/Atrog-in-1)(P<0.01 and P<0.05,respectively).(2)Compared with group M,group EM showed significant-ly greater heart weight(P<0.05);increased left ventricular posterior wall thickness at end-diastole(LVPWd),LVEF,FS and SV(P<0.05),as well as the larger cardiomyocyte CSA and total mTOR,p-mTOR and the p-mTOR/mTOR ratio(P<0.05),but reduced MuRF-1 and Atrogin-1 expression(P<0.05).Conclusion Four weeks of aerobic exercise preconditioning ameliorated myocardial atrophy and improved systolic cardiac function in mice bearing subcutaneously transplanted CT26 tumors.Such beneficial effects may be associated with exercise-induced down regulation of the protein degradation mediators MuRF-1 and Atrogin-1 and up regulation of total mTOR and p-mTOR.

Objective To investigate the effects of aerobic exercise and different exercise habits on skeletal muscle function and the possible molecular mechanisms in colorectal cancer-loaded mice.Methods Thirty-five 5-week-old BABL/c male mice were acclimatized to feeding for 1 week and then divided randomly into the following groups:control(D),tumor(M),exercise preconditioning(QAM),lifetime exercise(AM),and exercise(HAM)groups(n=7 mice per group).Mice in the QAM and AM groups underwent aerobic exercise regimen 1 from weeks 2～6.At week 7,mice in the experimental groups received 0.2 mL of CT26 colon cancer cell suspension subcutaneously in the dorsal aspect of the left hind limb,while control mice received 0.2 mL of saline at the corresponding site.Mice in the AM and HAM groups were subjected to aerobic exercise regimen 2 for weeks 7～9.The general status and skeletal muscle mass and function were monitored in all mice throughout the experiments.After completion of the experiment,samples were collected and the cross-sectional area of gastrocnemius muscle fibers(CSA)was measured by hematoxylin and eosin staining and expression levels of proteins related to synthesis and catabolism of the gastrocnemius muscle were analyzed by Western Blot.Results(1)The weight ratio of the gastrocnemius muscle was significantly lower in mice in the M,QAM,and HAM groups compared with group D,and was significantly higher in AM mice compared with M,QAM,and HAM mice.(2)Grip strength,endurance,skeletal muscle circumference,and CSA were significantly lower in group D mice compared with the other groups,and was most enhanced in group HAM.Endurance and CSA were consistently enhanced in groups QAM,AM,and HAM.(3)Muscle RING-finger protein-1(MuRF1)expression levels were significantly lower in groups M,QAM,AM,and HAM than in group D,significantly lower in groups AM and HAM than in group M,and significantly lower in group HAM than in group QAM.(4)Fibronectin type Ⅲ domain-containing protein 5(FNDC5)expression levels were significantly lower in group M than in groups D and QAM.(5)Peroxisome proliferator-activated receptor gamma coactivator 1-alpha expression levels were significantly lower in the QAM and HAM groups compared with group M.(6)Expression levels of phospho(p)-AMP-activated protein kinase(AMPK)/AMPK and p-AMPK were significantly higher in group QAM than in groups D and M,p-AMPK expression significantly lower in groups AM and HAM was than in group QAM,and AMPK expression was significantly lower in groups QAM,AM,and HAM than in group D.Conclusions Exercise preconditioning and continuous aerobic exercise can improve skeletal muscle mass and function in CT26 colon cancer-loaded mice by activating AMPK phosphorylation to stimulate skeletal muscle secretion of FNDC5,thereby regulating the expression of MuRF1 protein.

Objective To explore the effect of aerobic exercise on sarcopenia in CT26 tumor mice through the gut microbiota-skeletal muscle axis and its potential mechanism.Methods Forty-eight SPF BALB/c male mice aged 8 weeks were randomly divided into a normal control group(group NC,n=12),a normal control+aerobic exercise group(group NA,n=12),a CT26 tumor-associated sarco-penia group(group TS,n=12)and a CT26 tumor-associated sarcopenia+aerobic exercise group(group TSA,n=12).After a 2-week adaptive exercise period,CT26 cell suspension(0.2 mL,1×107 cells/mL)was subcutaneously injected into the dorsal region of mice in group TS and group TSA,while group NC and group NA were inoculated with 0.2 mL normal saline.One day later,group NA and group TSA underwent a 4-week aerobic treadmill running intervention(14 m/min,60 min/day,6 days/week).If a mouse failed to complete the target intensity on a given day,its running speed was reduced by 20%the following day.Moreover,group NA and group TSA received no exercise interven-tion.General health status of all groups was monitored throughout the study.The forelimb gripping force,rotarod walking time and the cross-sectional area of gastrocnemius muscle fibers were measured.Moreover,the ultrastructural changes of gastrocnemius were observed by transmission electron micro-scope,while the cecum contents were observed by 16S rRNA sequencing.Meanwhile,the pathological morphological changes of small intestine wall were observed using HE,while the contents of tumor ne-crosis factor-α(TNF-α),interleukin-6(IL-6),interleukin-1β(IL-1β)and lipopoly saccharide(LPS)of serum and gastrocnemius muscle were determined by using ELISA.Moreover,small intestine zonula occludens-1(ZO-1),Occludin and muscle ring finger 1(MuRF1),muscle atrophy F-box(MAF-bx),Toll-like receptor 4(TLR4)/myeloid differentiation factor 8(MyD88)/nuclear transcription factor-κB(NF-κB)signal pathway related proteins expression levels of gastrocnemius muscle,as well as muscle ring finger 1(MuRF1)and muscle atrophy F-box(MAF-bx)were detected using Western blot.Results(1)Subcutaneous tumors were prominent in group TS.The forelimb gripforce,wet weight and cross-sectional area of gastrocnemius,and rotarod walking time in group TS at the 5th and 6th weekends were significantly lower than group NC(P<0.01),while the relative expression levels of MuRF1 and MAF-bx proteins in the gastrocnemius muscle in group TS were significantly higher than the latter group(P<0.05,P<0.01).Moreover,transmission electron microscopy revealed sparse and dis-organized muscle fiber arrangement in group TS,with visible Z-lines but indistinct M-lines,as well as shortened,poorly defined,and thin sarcomeres.(2)The group TSA exhibited significantly higher α-diversity indices(Shannon,Chao1,and Observed species)in gut microbiota compared to group TS(P<0.05,P<0.01,P<0.05),while the β-diversity differed to some extent between the two groups.At phylum level,the F/B ratio was lower in group NA than that group NC,with that of group TSA low-er than group TS.At genus level,the relative abundances of Muribaculaceae,Bacteroides,Roseburia,and Alistipes in group NA were higher than group NC,and those of Alloprevotellaand Helicobacter were significantly lower,while those of Muribaculaceae,Lachnospiraceae_NK4A136_group,Roseburia,Bacteroides,Lachnospiraceae_UCG-001 of group TSA were significantly higher than group TS.Nota-bly,Roseburia and Alistipes were the most significantly enriched genera in group TSA and group TS(LDA score>4 for both).(3)The inflammatory cells of the small intestine wall in group TSA signifi-cantly reduced than those in group TS(P<0.05).Moreover,the expression level of ZO-1 proteins in the small intestine wall were significantly higher in group NA than group NC,and that of ZO-1 and Occludin proteins in the small intestine wall was significantly higher in group TSA than those in group TS(P<0.05).(4)The group NA exhibited significantly lower LPS concentrations in the gastrocne-mius muscle compared to group NC(P<0.05).Similarly,the group TSA showed reduced LPS levels in both serum and gastrocnemius compared to group TS(P<0.05).The relative protein expression of p-IκBα and p-NF-κB p65 significantly decreased in group TSA compared to group TS(P<0.05).The group TS displayed elevated concentrations of pro-inflammatory cytokines(TNF-α,IL-1β)in serum and gastrocnemius compared to group NC(P<0.01,P<0.05).The group TSA demonstrated significantly lower levels of TNF-α and IL-6 in these tissues in comparison with group TS(P<0.05,P<0.01).Conclusion Aerobic exercise can improve gut microbiota α diversity,adjusting its composition,improv-ing intestinal mucosal barrier function,reducing the LPS-induced pro-inflammatory response,and delay-ing skeletal muscle atrophy.The underlying mechanism may involve down regulation of TLR4/MyD88/NF-κB signaling in skeletal muscle,which has a positive effect on Gut-Muscle Axis.

Objective:To evaluate the effects of two dressing methods on wound healing and patient satisfaction after cosmetic suturing for pediatric facial trauma.Methods:A prospective randomized controlled trial was conducted at Dongying People′s Hospital from October 2022 to October 2023. A total of 180 pediatric patients [105 males, 75 females, aged 3-7 (3.9±1.4) years] with facial trauma requiring cosmetic suturing were enrolled in this study. Participants were randomly divided into the study group ( n=91) and control group ( n=89) using a random number table. During the first postoperative dressing change at 24 hours, the study group received saline cleaning followed by erythromycin ointment coverage, while the control group underwent iodine disinfection with gauze coverage. Pain intensity during the second dressing change was assessed using the Chinese version of the Children′s Hospital of Eastern Ontario pain scale (CHEOPS). Wound healing at 6-7 days post-suturing was evaluated using the Chinese version of the redness, edema, ecchymosis, discharge, and approximation (REEDA) scale. Scar appearance at 14 days was measured via the Stony Brook scar evaluation scale (SBSES). Complication rates (infection, dehiscence) and satisfaction rates were statistically analyzed. Results:During the second dressing change, the CHEOPS score was significantly lower in the study group (6.27±1.32) than that in the control group (6.89±1.21) ( P=0.001). At 6-7 days, the REEDA score in the study group (2.26±1.91) was significantly lower than that in the control group (3.07±2.13) ( P=0.008). At 14 days, the SBSES score was significantly lower in the study group [2.60±1.42) vs (3.89±1.50), P<0.001]. The infection rate was 1.09% (1/91) in the study group and 1.12% (1/89) in the control group, with two cases of epidermal dehiscence observed in the control group. The satisfaction rate in the study group was 93.41% (85/91), which was higher than that in the control group [85.49% (76/89), P=0.020]. Conclusion:Saline cleaning combined with erythromycin ointment coverage reduces pain during wound dressing change, facilitates early wound healing, and improves patient′s satisfaction.

Objective To explore the characteristics of vaginal microecology and vaginitis distribution of female patients in Xi'an,so as to provide reliable reference for clinical treatment.Methods A total of 102 124 women in Shaanxi Provincial People's Hospital from January 2018 to August 2023 were selected as the research objects.Vaginal secretions were collected from patients,and the vaginal microecology was detected and analyzed.Results Among 102 124 female patients,99.87%had vaginal microecological imbalance.The main disease types were vulvovaginal candidiasis(VVC),accounting for 16.03%,bacterial vaginitis(BV),accounting for 9.61%and trichomonal vaginitis(TV),accounting for 1.34%.Statistical analysis showed that the age of VVC,BV and TV patients was mainly 21～30 years old.The prevalence of VVC and BV in summer and autumn was higher than that in other seasons,while the prevalence of TV was relatively high in summer.In addition,there were 27 552 cases of simple vaginitis(26.98%)and 1 443 cases of mixed vaginitis(1.41%)in 101 995 female patients with vaginal microecology imbalance.In patients with mixed vaginitis,the BV+VVC combination accounted for the vast majority(79.00%),and the age group was mainly between 21 and 40 years old.Among the 28 995 patients with vaginitis,4 308 patients(14.86%)had recurrence,and the recurrence rate of simple vaginitis(11.44%,3 152/27 552)was much lower than that of mixed vaginitis(80.11%,1 156/1 443).Conclusion The main type of female simple vaginitis in Xi'an is VVC,which has a high prevalence in summer and autumn.The main type of mixed vaginitis is BV+VVC,Compared with simple vaginitis,patients with mixed infection are more likely to relapse.

Objective To investigate the effects of oral probiotics on gut microbiota diversity,colony structure,and intergroup differences in mice with subcutaneous colon cancer tumors,based on 16S rRNA sequencing technology.Methods Twenty-four 6-week-old male BALB/c mice were divided randomly into normal control group(NC group,n = 8),model group(M group,n = 8),and probiotic + model group(PM group,n = 8)after adaptive feeding for 1 week.Mice in the PM group were given 200 μL probiotic mixed solution(Bifidobacterium longum and Lactobacillus delbrueckii subsp.bulgaricus mixed lyophilized powder,2×108 colony-forming units)by gavage three times/week for 7 weeks,while the M group and PM group received 200 μL normal saline.At 10 weeks old,0.2 mL CT26.WT cell suspension(1×107/mL)was inoculated subcutaneously into the left hind limbs of M group and PM group,while NC group were inoculated with 0.2 mL normal saline.The general state of mice was observed,the growth of subcutaneous tumor was monitored,and the changes of intestinal flora structure were detected by 16S rRNA sequencing.Results The subcutaneous tumors of the M group were prominent,and the subcutaneous tumor volume and weight of the PM group were significantly reduced(P<0.05).Compared with NC group,Alpha diversity index was lower in the M group,and a significant difference of Beta diversity inter groups(P<0.01).And supplementation of probiotics had a certain effect on gut microbiota diversity in the M group.Compared with M group,the relative abundance of Bacteroidetes,Proteobacteria,Muribaculaceae,Bacteroides were higher in the PM group,while the relative abundance of Firmicutes,Desulfobacterota,Lachnospiraceae_NK4A136_group,Alistipes were lower in the PM group.LEfSe analysis showed that Muribaculaceae and Bacteroides in the PM group were different species with high abundance(LDA values>4).Conclusions Oral probiotics may improve the gut microbiota by increasing the relative abundance of beneficial Muribaculaceae and Bacteroides in subcutaneous tumors in mice with colon cancer.