Objective To investigate the effects of Toxoplasma gondii type Iand IIrhoptry protein 16 (ROP16) on the polarization and inflammatory response of mouse alveolar macrophages, so as to provide the scientific evidence for unveiling the immunoregulatory mechanisms following T. gondii infection in host cells and the clinical diagnosis and treatment of pulmonary toxoplasmosis. MethodsMouse alveolar macrophages served as blank controls, and mouse alveolar macrophages transfected with the empty lentiviral expression vector served as negative controls, and mouse alveolar macrophages transfected with lentiviral vectors overexpressing T. gondii type I and II ROP16 served as the type I and II ROP16 overexpression groups. Following puromycin selection, stably transfected cells that overexpressed type Iand IIROP16 were generated, observed for green fluorescence expression under a fluorescence microscope and verified using PCR, Western blotting and real-time quantitative reverse transcription PCR (RT-qPCR) assays. The expression of ROP16, inducible nitric oxide synthase (iNOS), arginase (Arg)-1, mannose receptor (CD206), cluster of differentiation 86 (CD86), NOD-like receptor thermal protein domain associated protein 3 (NLRP3), caspase-1, apoptosis-associated speck-like protein containing a CARD (ASC), and interleukin (IL)-1β proteins was determined in mouse alveolar macrophages using Western blotting assay, and the mRNA levels of ROP16, iNOS, IL-1β, IL-4, IL-12, IL-18, Arg-1, IL-10, IL-6, tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-β were detected in mouse alveolar macrophages using RT-qPCR assay. Results Fluorescence microscopy showed 90% of mouse alveolar macrophages producing green fluorescent signals in the type Iand II ROP16 overexpression groups and the negative control group. The relative ROP16 protein expression was 1.000 ± 0.000, 1.003 ± 0.020, 1.349 ± 0.055, and 1.376 ± 0.080 in mouse alveolar macrophages in the blank control group, negative control group, and type Iand IIROP16 overexpression groups (F = 35.30, P < 0.01), and the relative ROP16 mRNA expression was 1.007 ± 0.172, 2.030 ± 0.356, 1 409.579 ± 75.960, and 1 413.581 ± 27.712 in the blank control group, negative control group, and type Iand II ROP16 overexpression groups (F = 811.00, P < 0.01). The ROP16 expression was significantly higher in the type Iand IIROP16 overexpression groups than in the blank control group at both protein and mRNA levels (all P value < 0.01). Western blotting assay detected significant differences among the four groups in terms of iNOS, Arg-1, CD86, CD206, NLRP3, caspase-1, ASC, and IL-1β protein expression (F = 124.70, 82.40, 79.82, 919.40, 84.74, 39.85, 2 354.00 and 65.96, all P values < 0.05), and the expression of Arg-1, CD206, NLRP3, caspase-1, ASC, and IL-1β proteins was significantly higher in the type I ROP16 overexpression group than in the blank control group (all P values < 0.001), while the expression of iNOS, CD86, NLRP3, caspase-1, ASC, and IL-1β proteins was significantly higher in the type II ROP16 overexpression group than in the blank control group (all P values < 0.01). RT-qPCR assay detected significant differences among the four groups in terms of iNOS, IL-1β, IL-4, IL-12, IL-18, Arg-1, IL-10, IL-6, TNF-α, and TGF-β mRNA expression (F = 407.00, 1 528.00, 833.10, 267.90, 989.80, 161.80, 461.10, 5 529.00, 849.60 and 8 836.00, all P values < 0.05), and the Arg-1, IL-4, IL-10, and TGF-β mRNA expression was significantly higher in the type I ROP16 overexpression group than in the blank control group (all P values < 0.001), while the iNOS, IL-1β, IL-12, IL-18, IL-6, and TNF-α mRNA expression was significantly higher in the type II ROP16 overexpression group than in the blank control group (all P values < 0.001). Conclusions T. gondii type IROP16 may induce M2-dominant phenotypes of mouse alveolar macrophages, and type II ROP16 may induce M1-dominant phenotypes of mouse alveolar macrophages. Both T. gondii type I and II ROP16 may activate NLRP3, and mediate the activation of ASC, caspase-1 and IL-1β to promote inflammatory responses.

ObjectiveTo explore the effects of the Tai Chi training on bone density， bone turnover markers， and heart rate variability for people with high-risk osteoporosis， and to provide evidence for the prevention of osteoporosis at early stage. MethodsSixty-six cases of people with high risk of osteoporosis were included， and they were divided into 33 cases each in the intervention group and the control group using the random number table method. The control group received osteoporosis health education three times a week， and the intervention group received Tai Chi training under the guidance of a trainer three times a week for 40 mins each time on the basis of the control group， and both groups were intervened for 12 weeks. Dual-energy X-ray absorptiometry was used to measure the bone density of L₁~L₄ vertebrae， bilateral femoral necks and bilateral total hips in the two groups before and after the intervention； enzyme-linked immunosorbent assay was used to determine bone turnover markers before and after the intervention， including pro-collagen type Ⅰ pro-amino-terminal prepropyl peptide （P1NP） and β-collagen type Ⅰ cross-linking carboxy-terminal peptide （β-CTX）. Seven cases with good compliance in the intervention group were selected. After wearing the heart rate sensor， they successively performed Tai Chi training and walking activities recommended by the guideline for 20 mins each， and the heart rate variability （HRV） during exercise was collected， including time-domain indexes such as standard deviation of normal sinus intervals （SDNN）， root-mean-square of the difference between adjacent RR intervals （RMSSD）， frequency-domain metrics such as low-frequency power （LF）， high-frequency power （HF）， and low-frequency/high-frequency power ratio （LF/HF）， as well as nonlinear metrics such as approximate entropy （ApEn）， sample entropy （SampEn）. ResultsFinally， 63 cases were included in the outcome analysis， including 30 cases in the intervention group and 33 cases in the control group. After the intervention， the differences of L₁~L₄ vertebrae， bone density of bilateral femoral neck and bilateral total hip in the intervention group were not statistically significant when compared with those before intervention （P＞0.05）， while the bone density of all parts of the control group decreased significantly compared with that before intervention （P＜0.05）， and the difference in the bone density of the L₁~L₄ vertebrae， bilateral femoral neck， and the right total hip before and after the intervention of the intervention group was smaller than that of the control group （P＜0.05）. The differences in P1NP and β-CTX between groups before and after intervention was not statistically significant （P＞0.05）. Compared with walking exercise， LF decreased， HF increased and LF/HF decreased during Tai Chi exercise （P＜0.05）； the time domain indexes and non-linear indexes between groups had no statistically significant difference （P＞0.05）. ConclusionTai Chi exercise can maintain lumbar， hip， and femoral bone density and improve sympathetic/parasympathetic balance in people at high risk for osteoporosis， but cannot significantly improve bone turnover markers.

Objective:To investigate the incidence of postoperative complications in Chinese patients with gastric or colorectal cancer, and to evaluate the risk factors for postoperative complications.Methods:This was a national, multicenter, prospective, registry-based, cohort study of data obtained from the database of the Prevalence of Abdominal Complications After Gastro- enterological Surgery (PACAGE) study sponsored by the China Gastrointestinal Cancer Surgical Union. The PACAGE database prospectively collected general demographic characteristics, protocols for perioperative treatment, and variables associated with postoperative complications in patients treated for gastric or colorectal cancer in 20 medical centers from December 2018 to December 2020. The patients were grouped according to the presence or absence of postoperative complications. Postoperative complications were categorized and graded in accordance with the expert consensus on postoperative complications in gastrointestinal oncology surgery and Clavien-Dindo grading criteria. The incidence of postoperative complications of different grades are presented as bar charts. Independent risk factors for occurrence of postoperative complications were identified by multifactorial unconditional logistic regression.Results:The study cohort comprised 3926 patients with gastric or colorectal cancer, 657 (16.7%) of whom had a total of 876 postoperative complications. Serious complications (Grade III and above) occurred in 4.0% of patients (156/3926). The rate of Grade V complications was 0.2% (7/3926). The cohort included 2271 patients with gastric cancer with a postoperative complication rate of 18.1% (412/2271) and serious complication rate of 4.7% (106/2271); and 1655 with colorectal cancer, with a postoperative complication rate of 14.8% (245/1655) and serious complication rate of 3.0% (50/1655). The incidences of anastomotic leakage in patients with gastric and colorectal cancer were 3.3% (74/2271) and 3.4% (56/1655), respectively. Abdominal infection was the most frequently occurring complication, accounting for 28.7% (164/572) and 39.5% (120/304) of postoperative complications in patients with gastric and colorectal cancer, respectively. The most frequently occurring grade of postoperative complication was Grade II, accounting for 65.4% (374/572) and 56.6% (172/304) of complications in patients with gastric and colorectal cancers, respectively. Multifactorial analysis identified (1) the following independent risk factors for postoperative complications in patients in the gastric cancer group: preoperative comorbidities (OR=2.54, 95%CI: 1.51-4.28, P<0.001), neoadjuvant therapy (OR=1.42, 95%CI:1.06-1.89, P=0.020), high American Society of Anesthesiologists (ASA) scores (ASA score 2 points:OR=1.60, 95% CI: 1.23-2.07, P<0.001, ASA score ≥3 points:OR=0.43, 95% CI: 0.25-0.73, P=0.002), operative time >180 minutes (OR=1.81, 95% CI: 1.42-2.31, P<0.001), intraoperative bleeding >50 mL (OR=1.29,95%CI: 1.01-1.63, P=0.038), and distal gastrectomy compared with total gastrectomy (OR=0.65,95%CI: 0.51-0.83, P<0.001); and (2) the following independent risk factors for postoperative complications in patients in the colorectal cancer group: female (OR=0.60, 95%CI: 0.44-0.80, P<0.001), preoperative comorbidities (OR=2.73, 95%CI: 1.25-5.99, P=0.030), neoadjuvant therapy (OR=1.83, 95%CI:1.23-2.72, P=0.008), laparoscopic surgery (OR=0.47, 95%CI: 0.30-0.72, P=0.022), and abdominoperineal resection compared with low anterior resection (OR=2.74, 95%CI: 1.71-4.41, P<0.001). Conclusion:Postoperative complications associated with various types of infection were the most frequent complications in patients with gastric or colorectal cancer. Although the risk factors for postoperative complications differed between patients with gastric cancer and those with colorectal cancer, the presence of preoperative comorbidities, administration of neoadjuvant therapy, and extent of surgical resection, were the commonest factors associated with postoperative complications in patients of both categories.

Objective:To investigate the incidence of postoperative complications in Chinese patients with gastric or colorectal cancer, and to evaluate the risk factors for postoperative complications.Methods:This was a national, multicenter, prospective, registry-based, cohort study of data obtained from the database of the Prevalence of Abdominal Complications After Gastro- enterological Surgery (PACAGE) study sponsored by the China Gastrointestinal Cancer Surgical Union. The PACAGE database prospectively collected general demographic characteristics, protocols for perioperative treatment, and variables associated with postoperative complications in patients treated for gastric or colorectal cancer in 20 medical centers from December 2018 to December 2020. The patients were grouped according to the presence or absence of postoperative complications. Postoperative complications were categorized and graded in accordance with the expert consensus on postoperative complications in gastrointestinal oncology surgery and Clavien-Dindo grading criteria. The incidence of postoperative complications of different grades are presented as bar charts. Independent risk factors for occurrence of postoperative complications were identified by multifactorial unconditional logistic regression.Results:The study cohort comprised 3926 patients with gastric or colorectal cancer, 657 (16.7%) of whom had a total of 876 postoperative complications. Serious complications (Grade III and above) occurred in 4.0% of patients (156/3926). The rate of Grade V complications was 0.2% (7/3926). The cohort included 2271 patients with gastric cancer with a postoperative complication rate of 18.1% (412/2271) and serious complication rate of 4.7% (106/2271); and 1655 with colorectal cancer, with a postoperative complication rate of 14.8% (245/1655) and serious complication rate of 3.0% (50/1655). The incidences of anastomotic leakage in patients with gastric and colorectal cancer were 3.3% (74/2271) and 3.4% (56/1655), respectively. Abdominal infection was the most frequently occurring complication, accounting for 28.7% (164/572) and 39.5% (120/304) of postoperative complications in patients with gastric and colorectal cancer, respectively. The most frequently occurring grade of postoperative complication was Grade II, accounting for 65.4% (374/572) and 56.6% (172/304) of complications in patients with gastric and colorectal cancers, respectively. Multifactorial analysis identified (1) the following independent risk factors for postoperative complications in patients in the gastric cancer group: preoperative comorbidities (OR=2.54, 95%CI: 1.51-4.28, P<0.001), neoadjuvant therapy (OR=1.42, 95%CI:1.06-1.89, P=0.020), high American Society of Anesthesiologists (ASA) scores (ASA score 2 points:OR=1.60, 95% CI: 1.23-2.07, P<0.001, ASA score ≥3 points:OR=0.43, 95% CI: 0.25-0.73, P=0.002), operative time >180 minutes (OR=1.81, 95% CI: 1.42-2.31, P<0.001), intraoperative bleeding >50 mL (OR=1.29,95%CI: 1.01-1.63, P=0.038), and distal gastrectomy compared with total gastrectomy (OR=0.65,95%CI: 0.51-0.83, P<0.001); and (2) the following independent risk factors for postoperative complications in patients in the colorectal cancer group: female (OR=0.60, 95%CI: 0.44-0.80, P<0.001), preoperative comorbidities (OR=2.73, 95%CI: 1.25-5.99, P=0.030), neoadjuvant therapy (OR=1.83, 95%CI:1.23-2.72, P=0.008), laparoscopic surgery (OR=0.47, 95%CI: 0.30-0.72, P=0.022), and abdominoperineal resection compared with low anterior resection (OR=2.74, 95%CI: 1.71-4.41, P<0.001). Conclusion:Postoperative complications associated with various types of infection were the most frequent complications in patients with gastric or colorectal cancer. Although the risk factors for postoperative complications differed between patients with gastric cancer and those with colorectal cancer, the presence of preoperative comorbidities, administration of neoadjuvant therapy, and extent of surgical resection, were the commonest factors associated with postoperative complications in patients of both categories.

Objective:To investigate blood glucose management in elderly diabetic patients and the factors that affected achieving high rates of achieving it.Methods:The quality of blood glucose control by elderly diabetic patients who visited five community health service centers in Beijing in June 2022 was surveyed retrospectively using a questionnaire.Participants were divided into the high-quality group and not high-quality groups by the criteria of glycosylated hemoglobin(HbA 1C)<7% without hypoglycemia and weight gain.Single factor analysis and multiple-stepwise Logistic regression analysis were used to identify the relative risk of factors affecting the achievement of good glucose management. Results:A total of 287 valid questionnaires were collected, including 80 cases(27.9%)in the high-quality group and 207 cases(72.1%)in the not high-quality group.There were significant differences in sex, course of disease, occurrence of hypoglycemia, number of chronic complications, medication, alcohol consumption, dietary changes, missed medication doses, prolonged outpatient visit intervals, and depressive mood between the two groups( P<0.05).Multivariate stepwise logistic regression analysis showed that insulin use, missed medication ≥ 1 time/week, and prolonged outpatient visit intervals were independent risk factors for good control( P<0.05). Conclusions:The percentage of elderly diabetes patients with good blood glucose control was low.Factors affecting the rate included insulin use, medication compliance, and prolonged outpatient visit intervals.

Objective:To analyze the clinical manifestations, genetic and hematological test results of patients with sitosteronism (STSL) complicated with cardiovascular and cerebrovascular events.Methods:Clinical data were collected from 11 STSL patients at the outpatient department of Ruijin Hospital affiliated to Shanghai Jiaotong University School of Medicine between November 2020 to June 2023. The whole exome sequencing technology was used to detect gene mutations associated with lipid metabolism, the serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were tested by the enzyme endpoint method; serum phytosterol levels by high-performance liquid chromatography; serum concentration of C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor (TNF-α) by enzyme-linked immunosorbent assay, concentration of fibrinogen, the activity of protein C and coagulation factor Ⅷ (FⅧ) by the coagulation method; the antigen and activity of von Willebrand factor (vWF) by immunoturbidimetric assay; and the activity of antithrombin Ⅲ (ATⅢ) by chromogenic substrate assay.Results:There were 3 cases of coronary heart disease, 6 cases of cerebral infarction, 2 cases of coronary heart disease combined with cerebral infarction, 4 cases of eyelid melasma, and 2 cases of arthritis. Gene mutation was as follows: ABCG5 gene mutation including exon9: c G1166A: p R389H, exon9: c T1195C: p F399L, exon12: c.1762+1G>A, and ABCG8 gene mutation including exon 11 c.1720G>A: p.Gly574Arg, exon4:c.445_453del:p.A149_V151del, exon13 c.1949T>G: p.Leu650Arg. The percent of stomatocytes in the peripheral blood swears was (11.3±8.6)%. The concentrations of TC, LDL-C and sitosterol was (6.8±2.4), (4.4±2.0) mmol/L and 40.0 (22.0, 203.7) μmol/L. The level of CRP, interleukin IL-6, and TNF-α was 15.5 (7.2, 29.6)mg/L, (4.2±2.0) pg/ml and (6.7±1.5) pg/ml, respectively.The activity of PC, FⅧ and ATⅢ was (114±51)%, (110±41)% and (83±33)%. The values of FIB was (3.2±1.4)g/L.vWF antigen and vWF activity was (305±168)% and (275±112)%.Conclusions:STSL patients combined with cardiovascular and cerebrovascular events not only had complex dysfunctional lipid metabolism related gene defects, but also had significantly increased hematological indicators such as inflammatory mediator CRP, coagulation parameter vWF.

Age-dependent loss of skeletal muscle mass and function is a feature of sarcopenia, and increases the risk of many aging-related metabolic diseases. Here, we report phenotypic and single-nucleus transcriptomic analyses of non-human primate skeletal muscle aging. A higher transcriptional fluctuation was observed in myonuclei relative to other interstitial cell types, indicating a higher susceptibility of skeletal muscle fiber to aging. We found a downregulation of FOXO3 in aged primate skeletal muscle, and identified FOXO3 as a hub transcription factor maintaining skeletal muscle homeostasis. Through the establishment of a complementary experimental pipeline based on a human pluripotent stem cell-derived myotube model, we revealed that silence of FOXO3 accelerates human myotube senescence, whereas genetic activation of endogenous FOXO3 alleviates human myotube aging. Altogether, based on a combination of monkey skeletal muscle and human myotube aging research models, we unraveled the pivotal role of the FOXO3 in safeguarding primate skeletal muscle from aging, providing a comprehensive resource for the development of clinical diagnosis and targeted therapeutic interventions against human skeletal muscle aging and the onset of sarcopenia along with aging-related disorders.
Animals ; Humans ; Sarcopenia/metabolism* ; Forkhead Box Protein O3/metabolism* ; Muscle, Skeletal/metabolism* ; Aging/metabolism* ; Primates/metabolism*

Objective:To investigate changes in the self-management ability of chronic diseases in elderly diabetic patients during the novel coronavirus pneumonia pandemic.Methods:A multi-stage cluster sampling method was used to retrospectively collect diabetes management information from elderly diabetic patients treated in five community health service centers in Beijing in June 2022, including 295 elderly diabetic patients, and changes in management of their self-care practices such as diet, exercise, medical treatment and medication, blood glucose monitoring, complication management, and psychological states before and after the outbreak(2019-2022)were analyzed.Results:In 295 elderly diabetic patients, increased glycated hemoglobin( P<0.05)and body mass index(BMI)( P<0.05)were observed during the pandemic.Among 115 patients with underlying diabetic complications, 75.7%(87)of patients had worsening symptoms of chronic complications of diabetes and a shortened weekly exercise time[124(60, 300)min vs.140(60, 300)min, Z=6.00, P<0.05].The number of weekly blood glucose tests was reduced(5.6±4.2 vs.5.8±4.3, t=3.17, P<0.05).The weekly time spent interacting with family members increased( P<0.05).There were no significant differences in body weight, sleep time, and number of times of forgetting to take medication per week before and after the outbreak( P>0.05).21.0% of patients had a decrease in the number of hospital visits, and 72.2% of patients experienced low mood and increased adverse psychological emotions during the pandemic. Conclusions:The pandemic has had a negative impact on the management of chronic diseases in elderly diabetic patients, mainly reflected in the reduction of exercise time and blood glucose monitoring.It also affected regular hospital visits of patients, resulting in negative psychological emotions, poor blood glucose control, increased BMI, and aggravated symptoms of chronic complications, compared with their pre-pandemic conditions.

Objective:To investigate the impact of achievement goals on the academic achievement of medical students.Methods:In May to June of 2019, an online questionnaire survey was performed for data collection, and the stratified sampling method was used for sampling. Demographic factors, Achievement Goal Scale, and Academic Achievement Scale were used in this study, and descriptive statistics, the Pearson correlation analysis, and the multivariate linear hierarchical regression analysis were performed to analyze the impact of achievement goals on the academic achievement of medical students.Results:For these medical students, the mean value of achievement-near to the goal orientation was (3.45±0.77), the mean value of achievement-dodge the goal orientation was (3.43±0.80), and the mean value of mastery goal orientation was (3.85±0.66). Achievement-near to the goal orientation had a significant positive impact on academic achievement ( β=0.336, P<0.01), and mastery goal orientation also had a significant positive impact on academic achievement ( β=0.540, P<0.01). Conclusion:The achievement goals dominated by mastery goal orientation is the most beneficial dimension for the development of medical students.

Objective:To investigate the influencing factors of recurrence after radical resection of middle and low rectal cancer, and to establish a prediction model based on magnetic resonance imaging (MRI) measurement of perirectal fat content and investigate its application value.Methods:The retrospective cohort study was constructed. The clinicopathological data of 254 patients with middle and low rectal cancer who were admitted to Tianjin Union Medical Center from December 2016 to December 2021 were collected. There were 188 males and 66 females, aged (61±9)years. All patients underwent radical resection of rectal cancer and routine pelvic MRI examina-tion. Observation indicators: (1) follow-up and quantitative measurement of perirectal fat content; (2) factors influencing tumor recurrence after radical resection of middle and low rectal cancer; (3) construction and evaluation of the nomogram prediction model of tumor recurrence after radical resection of middle and low rectal cancer. Measurement data with normal distribution were represented as Mean± SD, and measurement data with skewed distribution were represented as M(rang) and M( Q1, Q2). Count data were described as absolute numbers. Univariate and multivariate analyses were conducted using the COX regression model. The rms software package (4.1.3 version) was used to construct the nomogram and calibration curve. The survival software package (4.1.3 version) was used to calculate the C-index. The ggDCA software package (4.1.3 version) was used for decision curve analysis. Results:(1) Follow-up and quantitative measurement of perirectal fat content. All 254 patients were followed up for 41.0(range, 1.0?59.0)months after surgery. During the follow-up period, there were 81 patients undergoing tumor recurrence with the time to tumor recurrence as 15.0(range, 1.0?43.0)months, and there were 173 patients without tumor recurrence. The preoperative rectal mesangial fascia envelope volume, preoperative rectal mesangial fat area, preoperative rectal posterior mesangial thickness were 159.1(68.6,266.5)cm3, 17.0(5.1,34.4)cm2, 1.2(0.4,3.2)cm in the 81 patients with tumor recurrence, and 178.5(100.1,310.1)cm3, 19.8(5.3,40.2)cm2 and 1.6(0.3,3.7)cm in the 173 patients without tumor recurrence. (2) Factors influencing tumor recurrence after radical resection of middle and low rectal cancer. Results of multivariate analysis showed that poorly differentiated tumor, tumor pathological N staging as N1?N2 stage, rectal posterior mesangial thickness ≤1.43 cm, magnetic resonance extra mural vascular invasion, tumor invasion surrounding structures were independent risk factors of tumor recurrence after radical resection of middle and low rectal cancer ( hazard ratio=1.64, 2.20, 3.19, 1.69, 4.20, 95% confidence interval as 1.03?2.61, 1.29?3.74, 1.78?5.71, 1.02?2.81, 2.05?8.63, P<0.05). (3) Construction and evaluation of the nomogram prediction model of tumor recurrence after radical resection of middle and low rectal cancer. Based on the results of multivariate analysis, the tumor differentiation, tumor pathological N staging, rectal posterior mesangial thickness, magnetic resonance extra mural vascular invasion, tumor invasion surrounding structures were included to construct the nomogram predic-tion model of tumor recurrence after radical resection of middle and low rectal cancer. The total score of these index in the nomogram prediction model corresponded to the probability of post-operative tumor recurrence. The C-index of the nomogram was 0.80, indicating that the prediction model with good prediction accuracy. Results of calibration curve showed that the nomogram prediction model with good prediction ability. Results of decision curve showed that the prediction probability threshold range was wide when the nomogram prediction model had obvious net benefit rate, and the model had good clinical practicability. Conclusions:Poorly differentiated tumor, tumor pathological N staging as N1?N2 stage, rectal posterior mesangial thickness ≤1.43 cm, magnetic resonance extra mural vascular invasion, tumor invasion surrounding structures are independent risk factors of tumor recurrence after radical resection of middle and low rectal cancer. Nomogram prediction model based on MRI measurement of perirectal fat content can effectively predict the probability of postoperative tumor recurrence.