OBJECTIVE To explore the changes of serum Toll-like receptor(TLR)2,TLR4 and 25 hydroxyvitamin D[25(OH)D]in the general anesthesia orthopedic surgery patients with postoperative pulmonary infections and analyze the distribution and drug resistance of pathogens.METHODS A total of 59 general anesthesia orthopedic surgery patients with postoperative pulmonary infections who were treated in Tianjin Fifth Central Hospital from Jul.2019 to Jul.2024 were chosen as the infection group,meanwhile,65 patients who underwent the same surger-y but did not have postoperative pulmonary infection or other acute and chronic infections were chosen as the non-infection group.The etiological characteristics of the postoperative pulmonary infections and the drug re-sistance rates were analyzed.The clinical data and the levels of serum TLR2,TLR4 and 25(OH)D were observed and compared between the two groups of patients.The values of the above indicators in diagnosis of the postopera-tive pulmonary infections in the general anesthesia orthopedic surgery were analyzed.RESULTS Totally 63 strains of pathogens were isolated from the 59 general anesthesia orthopedic surgery patients with postoperative pulmona-ry infections,36(57.14％)of which were gram-negative bacteria.3 of 15 Pseudomonas aeruginosa strains were resistant to meropenem;4 of 12 Klebsiella pneumoniae strians were resistant to meropenem;all of the 11 Staph-ylococcus aureus strains were methicilin-resistant S.aureus.The proportions of patients with age,hypoproteine-mia and diabetes mellitus,the serum TLR2 and TLR4 levels were higher in the infection group than in the non-infection group(P＜0.05),while the 25(OH)D level of the infection group was lower than that of the no in-fection group(P＜0.05).The area under the curves(AUCs)of serum TLR2,TLR4,25(OH)D and the joint de-tection of the above indicators were respectively 0.817,0.801,0.787 and 0.917 in diagnosis of postoperative pul-monary infections in the general anesthesia orthopedic surgery patients,and the AUC of the joint detection of the indicators was greater than that of the single detection(P＜0.05).CONCLUSIONS The general anesthesia or-thopedic surgery patients with postoperative pulmonary infections show high expressions of serum TLR2 and TLR4 and the low expression of 25(OH)D.The joint detection of the above indexes has higher diagnostic value.The gram-negative bacteria are dominant among the pathogens causing the infections.The pathogens vary in the drug resistance.

Objective:To understand the awareness of influenza and influenza vaccine, influenza incidence, influenza vaccination status and intention and related factors in primary and secondary school teachers.Methods:Cross-sectional study design and stratified random sampling method were used to select 5 teachers from each of 51 primary schools and 40 middle schools in a district of Beijing from April 17 to 21, 2024. A questionnaire survey was conducted in the selected teachers with an estimated sample size of 1 040. The survey collected the information about their demographic characteristics, awareness of influenza and influenza vaccine, influenza incidence, influenza vaccination status and intention. Multivariate logistic regression model was used to analyze the factors related to influenza vaccination status and intention.Results:In the 975 primary and secondary school teachers, the awareness of susceptibility and severity of influenza and the benefits of influenza vaccination were high. In terms of safety of influenza vaccine, 48.00% (468/975) of the teachers believed that adverse reaction would occur after the vaccination. Influenza like illness occurred in 41.13% (401/975) of the teachers during 2023-2024, and in these teachers, 40.15% (161/401) asked for leave from work due to illness, 40.90% (164/401) sought medical care and 32.93% (54/164) were influenza virus positive. In the 975 teachers, 13.95% (136/975) were vaccinated against influenza during 2023-2024 and 34.46% (336/975) were willing to be vaccinated against influenza during 2024-2025. Multivariate logistic regression analysis showed that being teacher in charge of a class (a OR=1.58, 95% CI: 1.06-2.35), believing that influenza vaccination could effectively prevent influenza (a OR=1.99, 95% CI: 1.05-3.80), believing that teachers' vaccination could improve students' willingness to be vaccinated (a OR=1.98, 95% CI: 1.12-3.50) were the positive factors for teachers' vaccination, and worrying about adverse reactions after the vaccination (a OR=0.52, 95% CI: 0.34-0.80) was the negative factor. Doctors' recommendation (a OR=2.62, 95% CI: 1.41-4.86) and free influenza vaccination (a OR=10.26, 95% CI: 5.17-20.39) were positively correlated with teachers' intention to influenza vaccination. Conclusions:Primary and secondary school teachers in a district of Beijing had high awareness of influenza and influenza vaccine, but their awareness of influenza vaccine safety should be improved. The incidence of influenza-related infection was high in the primary and secondary school teachers. The influenza vaccination rate was low and the willingness to receive influenza vaccination in following year was not strong. For the better prevention and control of influenza in schools, it is necessary to strengthen the health education in primary and secondary school teachers to improve their awareness of influenza vaccine safety and vaccination rate.

Objective:To compare knowledge graphs (KGs) constructed from standardized clinical pathways and actual examination records within 24 hours of emergency care for acute gastrointestinal hemorrhage (AGH), acute myocardial infarction (AMI), and intracerebral hemorrhage (ICH), and to visually analyze discrepancies between guideline recommendations and real-world practice, thereby exploring a novel methodology for clinical pathway optimization.Methods:KGs were developed using clinical pathway standards and actual examination data collected within the first 24 hours of emergency treatment for AGH, AMI, and ICH. Entity attributes were weighted to visually represent the frequency and extent of examination usage through variable node sizes in the KG. The constructed KGs were used to compare and analyze the differences in type and frequency of examinations performed relative to pathway standards.Results:The proportion of examination items with >50% adherence to clinical pathway standards within 24 hours was 76.92% for AGH, 44.44% for AMI, and 78.57% for ICH. Items from the clinical pathways that were not performed in over 50% of patients accounted for 15.38%, 27.78%, and 21.43% of cases, respectively. Non-pathway examinations increased by 9, 7, and 4 items for each condition, of which 17 items (85%) were performed at least once in more than half of the patients. Visualization via KGs revealed a reduction in redundant examinations by 38.64% between AGH and AMI, 35.00% between AGH and ICH, and 37.50% between AMI and ICH. Overall, a 54.84% reduction in redundant examinations was achieved across all three critical conditions.Conclusions:The visual KG approach effectively integrates both guideline-recommended and experience-driven examinations, serving as a correlational analysis tool to assess deviations between actual clinical practice and standardized pathways. It provides a quantitative foundation for optimizing clinical pathways, with potential for greater efficiency gains as more critical conditions are incorporated into the graph.

Objective:To investigate the impact of donor age on early postoperative liver function recovery in liver transplant recipients, as well as the incidence and risk factors for arterial complications following liver transplantation.Methods:A total of 518 patients who underwent liver transplantation at the Organ Transplantation Center of the Affiliated Hospital of Qingdao University between January 2021 and January 2024 were included in the study. Based on donor age, patients were classified into the elderly donor group (≥70 years, n=28) and the non-elderly donor group (<70 years, n=490). Liver function indicators—including aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TBIL), and direct bilirubin (DBIL)—were measured on postoperative days 1, 3, 7, and 14. The incidence of arterial complications, including hepatic artery thrombosis and hepatic artery stenosis, was recorded. Recipients were further categorized into the arterial complication group (n=26) and the non-arterial complication group (n=492) based on postoperative outcomes, and clinical characteristics of donors and recipients were compared. Binary logistic regression analysis was conducted to identify risk factors for arterial complications.Rusults:No significant differences were observed in baseline characteristics between the elderly and non-elderly donor groups ( P>0.05). However, the elderly donor group exhibited significantly higher AST, ALT, TBIL, and DBIL levels at all postoperative time points compared to the non-elderly donor group (all P<0.05). Specifically, on postoperative day 1, AST and ALT levels were (1,024.57±256.49) U/L and (756.24±145.89) U/L in the elderly donor group, compared to (895.23±225.19) U/L and (614.85±126.51) U/L in the non-elderly donor group. On day 3, AST and ALT levels were (402.46±71.61) U/L and (423.31±87.44) U/L versus (226.37±66.54) U/L and (256.79±70.25) U/L, respectively. On day 7, AST and ALT levels were (91.78±21.84) U/L and (92.36±21.62) U/L versus (68.41±18.38) U/L and (77.47±18.16) U/L. By day 14, AST and ALT levels were (67.52±10.35) U/L and (72.17±16.28) U/L versus (35.32±9.27) U/L and (48.56±14.10) U/L, respectively ( P<0.05 for all comparisons). For bilirubin indicators, TBIL and DBIL levels in the elderly donor group were also consistently higher than in the non-elderly donor group. On day 1, TBIL and DBIL were (95.76±21.93) μmol/L and (64.22±15.07) μmol/L, compared to (77.59±20.48) μmol/L and (51.18±12.96) μmol/L. By day 14, TBIL and DBIL levels had decreased to (41.26±8.30) μmol/L and (32.45±6.21) μmol/L, compared to (28.39±7.15) μmol/L and (20.58±5.04) μmol/L in the non-elderly donor group ( P<0.05 for all comparisons). The incidence of hepatic artery complications was 10.71% (3/28) in the elderly donor group and 4.69% (23/490) in the non-elderly donor group, with no statistically significant difference between the two groups ( P>0.05). Statistical analysis employing independent t-tests and χ2 tests demonstrated significant differences between the arterial complication group and non-arterial complication group in donor quality ratio ( P<0.05) and incidence of hepatic arterial hypoperfusion ( P<0.05). Multivariate binary logistic regression analysis, after adjusting for confounding factors (e.g., recipient gender, age, body mass index [BMI], primary disease, and donor-recipient blood type compatibility), identified recipient-to-donor mass ratio ( OR=1.352, P<0.05) and insufficient hepatic arterial blood flow ( OR=1.497, P<0.05) as independent risk factors for arterial complications following liver transplantation. Conclusion:Elderly liver donors can have a certain impact on early postoperative liver function recovery in liver transplant recipients, but have no significant impact on the occurrence of arterial complications after liver transplantation. The mass ratio of recipients to donors and insufficient hepatic arterial blood flow are independent risk factors for arterial complications after liver transplantation.

Objective:To explore the effect of Pegylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) with chemotherapy on breast cancer patients who got agranulocytosis of 3 to 4 degree, agranulocytosis with fever (FN) and the influential factors of relative dose intensity (RDI) chemotherapy scheme. Meantime, the value of CD34 + and CD45 in peripheral blood on predicting agranulocytosis of 3-4 degree were investigated.Methods:A total of 104 women with breast cancer were treated at Huzhou Maternal and Child Health Hospital and Cancer Hospital of Zhejiang Province from Jan. 2022 to Sep. 2023. All subjects received primary prevention with PEG-rhG-CSF during chemotherapy. The clinical risk factors of agranulocytosis, FN and RDI were analyzed. The levels of CD34 + and CD45 in peripheral blood samples were analyzed by flow cytometry. Then the predictive value of the receiver characteristic curve (ROC) for Grade 3 to 4 agranulocytosis after primary prophylaxis with PEG-rhG-CSF for breast cancer chemotherapy was evaluated.Results:Among 104 breast cancer patients who received primary prevention of PEG-rhG-CSF during chemotherapy, 28 patients had agranulocytosis of 3 to 4 grade, 10 patients got FN, and 12 patients developed RDI<85%. The results of single factor analysis showed that CD34 +, CD45 and chemotherapy scheme were the influential factors of agranulocytosis of 3 to 4 degree, and low RDI of chemotherapy scheme ( OR=0.584, OR=0.999, OR=2.299, OR=0.100, OR=0.999, OR=3.088, P<0.05) . It also showed that CD34 + and chemotherapy scheme were the influential factors of FN ( OR=0.099, OR=2.667, P<0.05) . Multivariate Logistic regression analysis showed that CD34 +, CD45 and intensive chemotherapy were the independent risk factors of agranulocytosis of 3 to 4 degree after primary prevention with PEG-rhG-CSF ( OR=0.602, OR=0.999, OR=20.174, P<0.05) . CD34 + and intensive chemotherapy scheme were the independent influential factors of FN and RDI of chemotherapy scheme after primary prevention with PEG-RHG-CSF ( OR=0.072, OR=33.934, OR=0.086, OR=54.788, P<0.05) . The area under the curve (AUC) of CD34 + were 0.767 (95% CI:0.659-0.876) , AUC of CD45 were 0.743 (95% CI:0.644-0.842) , and the AUC of combined two indexes was 0.825 (95% CI:0.730-0.920) , which was higher than that of single index. So AUC of CD34 + and CD45 can be used for predicting agranulocytosis of grade 3 to 4 in breast cancer patients receiving primary prophylaxis with PEG-rhG-CSF. Conclusions:The levels of CD34 + and CD45 in peripheral blood of breast cancer patients with agranulocytosis of grade 3 to 4 receiving primary prevention with PEG-rhG-CSF during chemotherapy are lower. Combined detection of CD34 + and CD45 in peripheral blood can predict the occurrence of agranulocytosis of grade 3 to 4 in breast cancer patients after primary prevention with PEG-rhG-CSF. Also it can provide a reliable basis for assessing the risk of grade 3 to 4 agranulocytosis.

Objective:To explore the effect of Pegylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) with chemotherapy on breast cancer patients who got agranulocytosis of 3 to 4 degree, agranulocytosis with fever (FN) and the influential factors of relative dose intensity (RDI) chemotherapy scheme. Meantime, the value of CD34 + and CD45 in peripheral blood on predicting agranulocytosis of 3-4 degree were investigated.Methods:A total of 104 women with breast cancer were treated at Huzhou Maternal and Child Health Hospital and Cancer Hospital of Zhejiang Province from Jan. 2022 to Sep. 2023. All subjects received primary prevention with PEG-rhG-CSF during chemotherapy. The clinical risk factors of agranulocytosis, FN and RDI were analyzed. The levels of CD34 + and CD45 in peripheral blood samples were analyzed by flow cytometry. Then the predictive value of the receiver characteristic curve (ROC) for Grade 3 to 4 agranulocytosis after primary prophylaxis with PEG-rhG-CSF for breast cancer chemotherapy was evaluated.Results:Among 104 breast cancer patients who received primary prevention of PEG-rhG-CSF during chemotherapy, 28 patients had agranulocytosis of 3 to 4 grade, 10 patients got FN, and 12 patients developed RDI<85%. The results of single factor analysis showed that CD34 +, CD45 and chemotherapy scheme were the influential factors of agranulocytosis of 3 to 4 degree, and low RDI of chemotherapy scheme ( OR=0.584, OR=0.999, OR=2.299, OR=0.100, OR=0.999, OR=3.088, P<0.05) . It also showed that CD34 + and chemotherapy scheme were the influential factors of FN ( OR=0.099, OR=2.667, P<0.05) . Multivariate Logistic regression analysis showed that CD34 +, CD45 and intensive chemotherapy were the independent risk factors of agranulocytosis of 3 to 4 degree after primary prevention with PEG-rhG-CSF ( OR=0.602, OR=0.999, OR=20.174, P<0.05) . CD34 + and intensive chemotherapy scheme were the independent influential factors of FN and RDI of chemotherapy scheme after primary prevention with PEG-RHG-CSF ( OR=0.072, OR=33.934, OR=0.086, OR=54.788, P<0.05) . The area under the curve (AUC) of CD34 + were 0.767 (95% CI:0.659-0.876) , AUC of CD45 were 0.743 (95% CI:0.644-0.842) , and the AUC of combined two indexes was 0.825 (95% CI:0.730-0.920) , which was higher than that of single index. So AUC of CD34 + and CD45 can be used for predicting agranulocytosis of grade 3 to 4 in breast cancer patients receiving primary prophylaxis with PEG-rhG-CSF. Conclusions:The levels of CD34 + and CD45 in peripheral blood of breast cancer patients with agranulocytosis of grade 3 to 4 receiving primary prevention with PEG-rhG-CSF during chemotherapy are lower. Combined detection of CD34 + and CD45 in peripheral blood can predict the occurrence of agranulocytosis of grade 3 to 4 in breast cancer patients after primary prevention with PEG-rhG-CSF. Also it can provide a reliable basis for assessing the risk of grade 3 to 4 agranulocytosis.

Objective:To understand the awareness of influenza and influenza vaccine, influenza incidence, influenza vaccination status and intention and related factors in primary and secondary school teachers.Methods:Cross-sectional study design and stratified random sampling method were used to select 5 teachers from each of 51 primary schools and 40 middle schools in a district of Beijing from April 17 to 21, 2024. A questionnaire survey was conducted in the selected teachers with an estimated sample size of 1 040. The survey collected the information about their demographic characteristics, awareness of influenza and influenza vaccine, influenza incidence, influenza vaccination status and intention. Multivariate logistic regression model was used to analyze the factors related to influenza vaccination status and intention.Results:In the 975 primary and secondary school teachers, the awareness of susceptibility and severity of influenza and the benefits of influenza vaccination were high. In terms of safety of influenza vaccine, 48.00% (468/975) of the teachers believed that adverse reaction would occur after the vaccination. Influenza like illness occurred in 41.13% (401/975) of the teachers during 2023-2024, and in these teachers, 40.15% (161/401) asked for leave from work due to illness, 40.90% (164/401) sought medical care and 32.93% (54/164) were influenza virus positive. In the 975 teachers, 13.95% (136/975) were vaccinated against influenza during 2023-2024 and 34.46% (336/975) were willing to be vaccinated against influenza during 2024-2025. Multivariate logistic regression analysis showed that being teacher in charge of a class (a OR=1.58, 95% CI: 1.06-2.35), believing that influenza vaccination could effectively prevent influenza (a OR=1.99, 95% CI: 1.05-3.80), believing that teachers' vaccination could improve students' willingness to be vaccinated (a OR=1.98, 95% CI: 1.12-3.50) were the positive factors for teachers' vaccination, and worrying about adverse reactions after the vaccination (a OR=0.52, 95% CI: 0.34-0.80) was the negative factor. Doctors' recommendation (a OR=2.62, 95% CI: 1.41-4.86) and free influenza vaccination (a OR=10.26, 95% CI: 5.17-20.39) were positively correlated with teachers' intention to influenza vaccination. Conclusions:Primary and secondary school teachers in a district of Beijing had high awareness of influenza and influenza vaccine, but their awareness of influenza vaccine safety should be improved. The incidence of influenza-related infection was high in the primary and secondary school teachers. The influenza vaccination rate was low and the willingness to receive influenza vaccination in following year was not strong. For the better prevention and control of influenza in schools, it is necessary to strengthen the health education in primary and secondary school teachers to improve their awareness of influenza vaccine safety and vaccination rate.

OBJECTIVE To explore the changes of serum Toll-like receptor(TLR)2,TLR4 and 25 hydroxyvitamin D[25(OH)D]in the general anesthesia orthopedic surgery patients with postoperative pulmonary infections and analyze the distribution and drug resistance of pathogens.METHODS A total of 59 general anesthesia orthopedic surgery patients with postoperative pulmonary infections who were treated in Tianjin Fifth Central Hospital from Jul.2019 to Jul.2024 were chosen as the infection group,meanwhile,65 patients who underwent the same surger-y but did not have postoperative pulmonary infection or other acute and chronic infections were chosen as the non-infection group.The etiological characteristics of the postoperative pulmonary infections and the drug re-sistance rates were analyzed.The clinical data and the levels of serum TLR2,TLR4 and 25(OH)D were observed and compared between the two groups of patients.The values of the above indicators in diagnosis of the postopera-tive pulmonary infections in the general anesthesia orthopedic surgery were analyzed.RESULTS Totally 63 strains of pathogens were isolated from the 59 general anesthesia orthopedic surgery patients with postoperative pulmona-ry infections,36(57.14％)of which were gram-negative bacteria.3 of 15 Pseudomonas aeruginosa strains were resistant to meropenem;4 of 12 Klebsiella pneumoniae strians were resistant to meropenem;all of the 11 Staph-ylococcus aureus strains were methicilin-resistant S.aureus.The proportions of patients with age,hypoproteine-mia and diabetes mellitus,the serum TLR2 and TLR4 levels were higher in the infection group than in the non-infection group(P＜0.05),while the 25(OH)D level of the infection group was lower than that of the no in-fection group(P＜0.05).The area under the curves(AUCs)of serum TLR2,TLR4,25(OH)D and the joint de-tection of the above indicators were respectively 0.817,0.801,0.787 and 0.917 in diagnosis of postoperative pul-monary infections in the general anesthesia orthopedic surgery patients,and the AUC of the joint detection of the indicators was greater than that of the single detection(P＜0.05).CONCLUSIONS The general anesthesia or-thopedic surgery patients with postoperative pulmonary infections show high expressions of serum TLR2 and TLR4 and the low expression of 25(OH)D.The joint detection of the above indexes has higher diagnostic value.The gram-negative bacteria are dominant among the pathogens causing the infections.The pathogens vary in the drug resistance.

Objective:To investigate the impact of donor age on early postoperative liver function recovery in liver transplant recipients, as well as the incidence and risk factors for arterial complications following liver transplantation.Methods:A total of 518 patients who underwent liver transplantation at the Organ Transplantation Center of the Affiliated Hospital of Qingdao University between January 2021 and January 2024 were included in the study. Based on donor age, patients were classified into the elderly donor group (≥70 years, n=28) and the non-elderly donor group (<70 years, n=490). Liver function indicators—including aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TBIL), and direct bilirubin (DBIL)—were measured on postoperative days 1, 3, 7, and 14. The incidence of arterial complications, including hepatic artery thrombosis and hepatic artery stenosis, was recorded. Recipients were further categorized into the arterial complication group (n=26) and the non-arterial complication group (n=492) based on postoperative outcomes, and clinical characteristics of donors and recipients were compared. Binary logistic regression analysis was conducted to identify risk factors for arterial complications.Rusults:No significant differences were observed in baseline characteristics between the elderly and non-elderly donor groups ( P>0.05). However, the elderly donor group exhibited significantly higher AST, ALT, TBIL, and DBIL levels at all postoperative time points compared to the non-elderly donor group (all P<0.05). Specifically, on postoperative day 1, AST and ALT levels were (1,024.57±256.49) U/L and (756.24±145.89) U/L in the elderly donor group, compared to (895.23±225.19) U/L and (614.85±126.51) U/L in the non-elderly donor group. On day 3, AST and ALT levels were (402.46±71.61) U/L and (423.31±87.44) U/L versus (226.37±66.54) U/L and (256.79±70.25) U/L, respectively. On day 7, AST and ALT levels were (91.78±21.84) U/L and (92.36±21.62) U/L versus (68.41±18.38) U/L and (77.47±18.16) U/L. By day 14, AST and ALT levels were (67.52±10.35) U/L and (72.17±16.28) U/L versus (35.32±9.27) U/L and (48.56±14.10) U/L, respectively ( P<0.05 for all comparisons). For bilirubin indicators, TBIL and DBIL levels in the elderly donor group were also consistently higher than in the non-elderly donor group. On day 1, TBIL and DBIL were (95.76±21.93) μmol/L and (64.22±15.07) μmol/L, compared to (77.59±20.48) μmol/L and (51.18±12.96) μmol/L. By day 14, TBIL and DBIL levels had decreased to (41.26±8.30) μmol/L and (32.45±6.21) μmol/L, compared to (28.39±7.15) μmol/L and (20.58±5.04) μmol/L in the non-elderly donor group ( P<0.05 for all comparisons). The incidence of hepatic artery complications was 10.71% (3/28) in the elderly donor group and 4.69% (23/490) in the non-elderly donor group, with no statistically significant difference between the two groups ( P>0.05). Statistical analysis employing independent t-tests and χ2 tests demonstrated significant differences between the arterial complication group and non-arterial complication group in donor quality ratio ( P<0.05) and incidence of hepatic arterial hypoperfusion ( P<0.05). Multivariate binary logistic regression analysis, after adjusting for confounding factors (e.g., recipient gender, age, body mass index [BMI], primary disease, and donor-recipient blood type compatibility), identified recipient-to-donor mass ratio ( OR=1.352, P<0.05) and insufficient hepatic arterial blood flow ( OR=1.497, P<0.05) as independent risk factors for arterial complications following liver transplantation. Conclusion:Elderly liver donors can have a certain impact on early postoperative liver function recovery in liver transplant recipients, but have no significant impact on the occurrence of arterial complications after liver transplantation. The mass ratio of recipients to donors and insufficient hepatic arterial blood flow are independent risk factors for arterial complications after liver transplantation.

Objective:To study the effects of fluoride on apoptosis and oxidative stress levels of spinal cord nerve cells in rats.Methods:A total of 54 6-week-old Sprague-Dawley female rats, weighing 150 - 200 g, were selected and fed for 1 week. They were divided into a control group [given deionized water containing 0 mg/L sodium fluoride (NaF)], a low fluoride group (given deionized water containing 50 mg/L NaF), and a high fluoride group (given deionized water containing 100 mg/L NaF) using a random number table method, with 18 rats in each group. All groups received standard feed. After 4, 8, and 12 weeks of fluoride exposure, six rats were selected from each group to observe the occurrence of dental fluorosis, and the motor function of hind limbs in rats was evaluated based on the Basso-Beattie-Bresnahan (BBB) score. Then the rats were anesthetized with 5% chloral hydrate via intraperitoneal injection and euthanized by cardiac puncture. Spinal cord tissue of the rats was collected to detect the activities of oxidative stress factors such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), as well as the contents of malondialdehyde (MDA) and catalase (CAT). After 12 weeks of fluoride exposure, morphologic changes in rat spinal cord neurons were observed using Nissl staining, and apoptosis of spinal cord nerve cells was detected using the TdT mediated dUTP nick end labeling (TUNEL) cell apoptosis detection kit. The Western blotting was used to detect the expression of B-lymphoblastoma-2 (Bcl-2) gene related X protein (Bax), Bcl-2 promoter (Bad), and Bcl-2 protein in rat spinal cord tissue; immunofluorescence staining was used to observe the expression of Bax and Bcl-2 protein in spinal cord neurons.Results:After 12 weeks of fluoride exposure, rats in both the low fluoride and high fluoride groups developed varying degrees of dental fluorosis; the differences of BBB scores of rats in the control, low fluoride, and high fluoride groups were statistically significant ( F = 14.09, P < 0.001). The differences of SOD [(124.04 ± 4.87), (96.66 ± 15.01), (91.12 ± 15.87) U/mg prot] and GSH-Px activitives [(561.92 ± 59.65), (456.83 ± 29.51), (385.07 ± 74.87) U/mg prot], MDA [(9.96 ± 1.50), (16.64 ± 2.05), (20.80 ± 3.37) nmol/mg prot] and CAT contents [(8.97 ± 1.05), (6.39 ± 0.97), (6.42 ± 0.83) nmol/mg prot] among the control, low fluoride, and high fluoride groups were statistically significant ( F = 11.17, 14.19, 30.12, 14.52, P < 0.05). Among them, the SOD, GSH-Px activities, and CAT content in the low fluoride and high fluoride groups were lower than those in the control group, while the MDA content was higher than that in the control group ( P < 0.05). The GSH-Px activity in the high fluoride group was lower than that in the low fluoride group, and MDA content was higher than that in the low fluoride group ( P < 0.05). The intact neuronal structures and clear visible nuclei were seen, and Nissl bodies were uniformly stained in the spinal cord neurons of the control group rats, with more numbers, and no apoptotic cells were observed; the staining of Nissl bodies in the spinal cord neurons of rats was uneven in the low fluoride and high fluoride groups, with fewer numbers, and more apoptotic cells. There were statistically significant differences in the apoptosis rate of spinal cord nerve cells and the expression levels of Bax, Bad, and Bcl-2 protein in the spinal cord tissues of rats in the control, low fluoride, and high fluoride groups ( F = 272.81, 35.53, 17.57, 92.50, P < 0.05). The results of immunofluorescence staining showed that there were statistically significant differences in the fluorescent intensity of Bax and Bcl-2 proteins in the spinal cord neurons of rats in the control, low fluoride, and high fluoride groups ( F = 12.67, 22.14, P < 0.05). Conclusion:Chronic fluorosis induces a decrease in antioxidant enzyme activity, an increase in lipid peroxidation levels, and an increase in neuronal apoptosis in the spinal cord of rats.