To analyze the clinical data and imaging examination data of a patient with metallic mercury poisoning from subcutaneous injection. The abdominal B-ultrasonograph results of the patient indicated multiple scattered hyperechoic spots accompanied by "comet tail" sign in the liver and right renal sinus, the nature of which was not clear and it was considered crystal deposition. The chest X-ray revealed scattered and multiple spot-like, snowflake-like and tree-cast-like high-density shadows in both lung fields. The chest computed tomography scan revealed multiple spot and patchy high-density shadows distributed in both lungs, considering hematogenous distribution deposits, and possible mercury poisoning. Laboratory test results showed that blood mercury level was 4.16 μmol/L and urine mercury level was 6 545.5 μg/g Cr. After 28 days of mercury chelation therapy, the abdominal ultrasound examination showed that the hyperechoic spots in the liver and right renal sinus were reduced compared with the previous examination. Metallic mercury poisoning from subcutaneous injection has specific manifestations in abdominal B-ultrasound imaging, which can provide a basis for the early diagnosis of metallic mercury poisoning in clinical practice and can be used to observe the efficacy of mercury chelation therapy.

Objective:To evaluate the characteristics of vaginal flora between normal and abnormal pregnant women throughout pregnancy.Methods:Vaginal swab specimens were collected from pregnant women in the first (<14 gestation weeks, GW), second (14~28 GW) and third trimester (>28 GW) in Anqing, Anhui Province from February 2018 to February 2020. Pregnant women were divided into normal and abnormal groups according to all clinical diagnosis. The sequences of 16S rRNA gene (V3-V4) from vaginal swabs were analyzed using QIIME2 platform. The differences in the dominance of Lactobacillus, community state type (CST) transition, Alpha diversity and Beta diversity were analyzed. Diversity data after log transition were used in the analysis of linear mixed model. Results:A total of 34 pregnant women (10 normal and 24 abnormal) with 102 samples were included for analysis. The composition of vaginal flora between two groups: the relative abundance of Lactobacillus was the highest at the genus level and Lactobacillus crispatus and Lactobacillus iners was the top two species with high relative abundance. The dominance of Lactobacillus, Alpha diversity and transition of CST were also similar. Both groups had a gradually decreased trend of Alpha diversity with GW, and the Chao1, Observed species and Faith′s PD indexes′ were different in different GW ( P<0.05). All Beta diversity metrics in normal group had descending trend, with lower value of the index of first distance which implied a higher microbiota stability, while Bray-Curtis, Weighted UniFrac distance had ascending trend in abnormal group, indicating lower stability. Jaccard distance′s first distance was statistically differed among GW and Unweighted UniFrac distance′s differed between normal and abnormal groups. Conclusions:The first distance of Unweighte UniFrac distance in abnormal pregnant women is higher than that of normal pregnant women and the vaginal flora in abnormal group has lower stability.

Objective:To study the characteristics of vaginal microbiota in pregnant women with premature rupture of membranes (PROM) and to establish prediction models for PROM.Methods:This study involved 35 women with preterm premature rupture of membranes (PPROM), 180 with term premature rupture of membranes (TPROM) and 255 term birth cases without premature rupture of membranes (TBWPROM, control group). The V3-V4 hypervariable region sequences in the vaginal samples collected at 16-28 weeks of gestation were detected by 16S rRNA gene next-generation sequencing. The differences in Alpha and Beta diversity, and the attributes and metabolic function prediction of each recognized species among the three groups were analyzed. Subsequently, a random forest model was used to establish the prediction models for PROM using vaginal microbiota species and environmental risk factors.Results:Compared with the control group, the Alpha diversity of the PPROM group was higher (Observed features, P=0.022; Faith_pd index, P=0.024) and Beta diversity was also significantly different (Unweighted UniFrac, P=0.010; Jaccard index, P=0.008). In PPROM cases, Megasphaera genomosp. typeⅠ was significantly increased ( P=0.017) and Lactobacillus mulieris was significantly decreased ( P=0.003). In the patients with TPROM, Megasphaera was significantly increased ( P=0.009) and Lactobacillus mulieris was significantly decreased ( P=0.002). In terms of functional pathways, sulfur oxidation ( P=0.021), methanogenesis from acetate ( P=0.036), L-histidine biosynthesis ( P=0.009), adenosylcobalamin biosynthesis ( P=0.041) and fucose degradation ( P=0.001) were significantly increased in patients with PPROM; L-histidine biosynthesis ( P<0.001) and fucose degradation ( P=0.030) were significantly increased in patients with TPROM. The prediction models were established using the random forest model with vaginal microbiota species and environmental risk factors and the prediction model for PPROM performed well [AUC: 0.739 (95%CI: 0.609-0.869), sensitivity: 0.928, specificity: 0.659, positive predictive value: 0.750, negative predictive value: 0.906], which had a certain reference value. Conclusions:Vaginal microbiota might be related to the development and progression of PROM. Studying the differences in vaginal microbiota might provide a new idea for the prevention and treatment of PROM. Functional prediction provided a direction for further research on the mechanism of PROM. The established prediction model could prevent the occurrence of PPROM and promote maternal and infant health.

Laparoscopic operations have become an indispensable therapeutic measure in surgical treatment due to the emerging trends of minimal invasiveness and precision in the field of surgery.Laparoscopic skills have gradually become part of the essential skills for young surgeons and hospitals at all levels are giving high priority to laparoscopic skills training.The innovation and development of simulative and virtual medical technology has given rise to effective ways and platforms for the training of laparoscopy surgeons in China.Based on the laparoscopy simulative virtual technology,our hospital gradually developed a systematic training and evaluation system for the laparoscopy training of surgical residents by offering theory courses on laparoscopy,conducting simulative and virtual systematic training,and developing assessment criteria for the training.Herein,we presented and shared our experience in applying laparoscopy simulative virtual technology in the training of surgical residents in order to promote the standardized residency training of laparoscopic skills in China and to provide reference for the implementation of standardized training of laparoscopic skills.

Objective:To study the characteristics and influencing factors of vaginal microbiota in normal pregnant women.Methods:This study was based on a cohort of pregnant women established in Anqing Municipal Hospital Affiliated to Anhui Medical University from February 2018 to February 2020. Vaginal samples of normal pregnant women who met the inclusion and exclusion criteria were ordered by the gestational weeks at sampling. Five samples were randomly selected from each gestational week group and if the samples were less than five, all samples were included. Sequencing of the V3-V4 region of the 16S rRNA gene was performed. Dominant species were analyzed by MicrobiomeAnalyst. Alpha diversity was measured with Chao1, Observed Features, Shannon diversity, Simpson diversity, Faith_pd and Pielou′s Evenness. The dominant status of Lactobacillus was also described and compared. Multiple linear regression and logistic regression were used to analyze the factors influencing vaginal microbiota. Analysis of variance and Kruskal Wallis test were used for statistical analysis of continuous variables, and Chi-square test and Fisher′s exact test were used for categorical data. The differences were considered statistically significant when the P value was less than 0.05. Results:This study enrolled 91 pregnant women (91 vaginal samples) with an average age of (27.37±3.60) years. There were 18, 56 and 17 vaginal samples collected at the median gestational age of 11.93 weeks (the first trimester), 19.43 weeks (the second trimester) and 38.29 weeks (the third trimester), respectively. The relative abundance of Firmicutes and Lactobacillus was 91.30% and 87.67%, respectively. Lactobacillus iners and Lactobacillus crispatus had a relative abundance of 43.95% and 36.33%, respectively. Moreover, Lactobacillus iners-dominated vaginal microbiota was detected in all trimesters. The number of samples with high relative abundance of Lactobacillus iners gradually decreased with gestational age. Lactobacillus crispatus-dominated vaginal microbiota was found in the second and third trimesters and the number of samples with high relative abundance gradually increased during pregnancy. The Alpha diversity of vaginal microbiota had a decreasing trend during the gestation. There were significant differences in Pielou′s Evenness diversity index of vaginal microbiota between different smoking groups ( P<0.05) and in Shannon diversity index between different drinking groups ( P<0.05). There were significant differences in Chao1, Observed Features and Faith_pd diversity index of vaginal microbiota between pregnant women with different education ( P<0.05) and in Shannon and Simpson diversity index between different income groups ( P<0.05). Conclusions:Vaginal microbiota was dominated by Lactobacillus in normal pregnant women. The dominance of Lactobacillus iners gradually decreased, while that of Lactobacillus crispatus increased during gestation. In normal pregnant women, the Alpha diversity of vaginal microbiota was correlated with smoking, drinking, education and family annual income. Smoking cessation and drinking before pregnancy were related to lower Alpha diversity of vaginal microbiota in pregnant women, while lower education and higher family income were associated with higher Alpha diversity.

Objective:To explore the effect of standardized surgical treatment and multidisciplinary treatment strategy on the treatment outcomes of gastric cancer patients.Methods:A single-center cohort study was carried out. Clinicopathological and long-term follow up data of primary gastric cancer patients were retrieved from the database of Surgical Gastric Cancer Patient Registry (SGCPR) in West China Hospital of Sichuan University. Finally, 4516 gastric cancer patients were included and were divided into three groups according to time periods (period 1 group: exploration stage of standardized surgical treatment, 2000 to 2006, 967 cases; period 2 group: application stage of standardized surgical treatment, 2007 to 2012, 1962 cases; period 3 group: optimization stage of standardized surgical treatment and application stage of multidisciplinary treatment strategy, 2013 to 2016, 1587 cases). Differences in clinical data, pathologic features, and prognosis were compared among 3 period groups. Follow-up information was updated to January 1, 2020. The overall follow-up rate was 88.9% (4016/4516) and median follow-up duration was 51.58 months. Survival curve was drawn by Kaplan-Meire method and compared with log-rank test. Univariate and multivariate analyses were performed by Cox proportional hazards model.Results:There were significant differences among period 1, period 2 and period 3 groups in the rates of D2/D2+ lymphadenectomy [14.4%(139/967) vs. 47.2%(927/1962) vs. 75.4%(1197/1587), χ 2=907.210, P<0.001], in the ratio of proximal gastrectomy [19.8%(191/967) vs. 16.6%(325/1962) vs. 8.2%(130/1587), χ 2=100.020, P<0.001], and in the median intraoperative blood loss (300 ml vs. 100 ml vs. 100 ml, H=1126.500, P<0.001). Besides, the increasing trend and significant difference were also observed in the median number of examined lymph nodes among period 1, period 2 and period 3 groups (14 vs. 26 vs. 30, H=987.100, P<0.001). Survival analysis showed that the 5-year overall survival rate was 55.3% in period 1, 55.2% in period 2 and 62.8% in period 3, and significant difference existed between period 3 and period 1 ( P=0.004). The Cox proportional hazards model analysis showed that treatment period (period 3, HR=0.820, 95%CI: 0.708 to 0.950, P=0.008), postoperative chemotherapy (HR=0.696, 95%CI: 0.631 to 0.768, P<0.001) and mid-low gastric cancer (HR=0.884, 95%CI: 0.804 to 0.973, P=0.011) were good prognostic factors. Whereas old age (≥65 years, HR=1.189, 95%CI: 1.084 to 1.303, P<0.001), palliative resection (R1/R2, HR=1.538,95%CI: 1.333 to 1.776, P<0.001), large tumor size (≥5 cm, HR=1.377, 95%CI: 1.239 to 1.529, P<0.001), macroscopic type III to IV (HR=1.165, 95%CI: 1.063 to 1.277, P<0.001) and TNM stage II to IV(II/I: HR=1.801,95% CI:1.500~2.162, P<0.001;III/I: HR=3.588, 95% CI: 3.028~4.251, P<0.001; IV/I: HR=6.114, 95% CI: 4.973~7.516, P<0.001) were independent prognostic risk factors. Conclusion:Through the implementation of standardized surgical treatment technology and multidisciplinary treatment model, the quality of surgery treatment and overall survival increase, and prognosis of gastric cancer patients has been improved.

Objective:To explore the effect of standardized surgical treatment and multidisciplinary treatment strategy on the treatment outcomes of gastric cancer patients.Methods:A single-center cohort study was carried out. Clinicopathological and long-term follow up data of primary gastric cancer patients were retrieved from the database of Surgical Gastric Cancer Patient Registry (SGCPR) in West China Hospital of Sichuan University. Finally, 4516 gastric cancer patients were included and were divided into three groups according to time periods (period 1 group: exploration stage of standardized surgical treatment, 2000 to 2006, 967 cases; period 2 group: application stage of standardized surgical treatment, 2007 to 2012, 1962 cases; period 3 group: optimization stage of standardized surgical treatment and application stage of multidisciplinary treatment strategy, 2013 to 2016, 1587 cases). Differences in clinical data, pathologic features, and prognosis were compared among 3 period groups. Follow-up information was updated to January 1, 2020. The overall follow-up rate was 88.9% (4016/4516) and median follow-up duration was 51.58 months. Survival curve was drawn by Kaplan-Meire method and compared with log-rank test. Univariate and multivariate analyses were performed by Cox proportional hazards model.Results:There were significant differences among period 1, period 2 and period 3 groups in the rates of D2/D2+ lymphadenectomy [14.4%(139/967) vs. 47.2%(927/1962) vs. 75.4%(1197/1587), χ 2=907.210, P<0.001], in the ratio of proximal gastrectomy [19.8%(191/967) vs. 16.6%(325/1962) vs. 8.2%(130/1587), χ 2=100.020, P<0.001], and in the median intraoperative blood loss (300 ml vs. 100 ml vs. 100 ml, H=1126.500, P<0.001). Besides, the increasing trend and significant difference were also observed in the median number of examined lymph nodes among period 1, period 2 and period 3 groups (14 vs. 26 vs. 30, H=987.100, P<0.001). Survival analysis showed that the 5-year overall survival rate was 55.3% in period 1, 55.2% in period 2 and 62.8% in period 3, and significant difference existed between period 3 and period 1 ( P=0.004). The Cox proportional hazards model analysis showed that treatment period (period 3, HR=0.820, 95%CI: 0.708 to 0.950, P=0.008), postoperative chemotherapy (HR=0.696, 95%CI: 0.631 to 0.768, P<0.001) and mid-low gastric cancer (HR=0.884, 95%CI: 0.804 to 0.973, P=0.011) were good prognostic factors. Whereas old age (≥65 years, HR=1.189, 95%CI: 1.084 to 1.303, P<0.001), palliative resection (R1/R2, HR=1.538,95%CI: 1.333 to 1.776, P<0.001), large tumor size (≥5 cm, HR=1.377, 95%CI: 1.239 to 1.529, P<0.001), macroscopic type III to IV (HR=1.165, 95%CI: 1.063 to 1.277, P<0.001) and TNM stage II to IV(II/I: HR=1.801,95% CI:1.500~2.162, P<0.001;III/I: HR=3.588, 95% CI: 3.028~4.251, P<0.001; IV/I: HR=6.114, 95% CI: 4.973~7.516, P<0.001) were independent prognostic risk factors. Conclusion:Through the implementation of standardized surgical treatment technology and multidisciplinary treatment model, the quality of surgery treatment and overall survival increase, and prognosis of gastric cancer patients has been improved.

OBJECTIVE: To compare the long-term survival outcomes of Siewert II adenocarcinoma of esophagogastric junction (AEG) between transthoracic (TT) approach and transabdominal (TA) approach. METHODS: The databases of Gastrointestinal Surgery Department and Thoracic Surgery Department in West China Hospital of Sichuan University from 2006 to 2014 were integrated. Patients of Siewert II AEG who underwent resection were retrospectively collected. INCLUSION CRITERIA: (1) adenocarcinoma confirmed by gastroscopy and biopsy; (2) tumor involvement in the esophagogastric junction line; (3) tumor locating from lower 5 cm to upper 5 cm of the esophagogastric junction line, and tumor center locating from upper 1 cm to lower 2 cm of esophagogastric junction line; (4)resection performed at thoracic surgery department or gastrointestinal surgery department; (5) complete follow-up data. Patients at thoracic surgery department received trans-left thoracic, trans-right thoracic, or transabdominothoracic approach; underwent lower esophagus resection plus proximal subtotal gastrectomy; selected two-field or three-field lymph node dissection; underwent digestive tract reconstruction with esophagus-remnant stomach or esophagus-tubular remnant stomach anastomosis above or below aortic arch using hand-sewn or stapler instrument to perform anastomosis. Patients at gastrointestinal surgery department received transabdominal(transhiatal approach), or transabdominothoracic approach; underwent total gastrectomy or proximal subtotal gastrectomy; selected D1, D2 or D2 lymph node dissection; underwent digestive tract reconstruction with esophagus-single tube jejunum or esophagus-jejunal pouch Roux-en-Y anastomosis, or esophagus-remnant stomach or esophagus-tubular remnant stomach anastomosis; completed all the anastomoses with stapler instruments. The follow-up ended in January 2018. The TNM stage system of the 8th edition UICC was used for esophageal cancer staging; survival table method was applied to calculate 3-year overall survival rate and 95% cofidence interval(CI); log-rank test was used to perform survival analysis; Cox regression was applied to analyze risk factors and calculate hazard ratio (HR) and 95%CI. RESULTS: A total of 443 cases of Siewert II AEG were enrolled, including 89 cases in TT group (with 3 cases of transabdominothoracic approach) and 354 cases in TA group. Median follow-up time was 50.0 months (quartiles:26.4-70.2). The baseline data in TT and TA groups were comparable, except the length of esophageal invasion [for length <3 cm, TA group had 354 cases(100%), TT group had 44 cases (49.4%), χ²=199.23,P<0.001]. The number of harvested lymph node in thoracic surgery department and gastrointestinal surgery department were 12.0(quartiles:9.0-17.0) and 24.0(quartiles:18.0-32.5) respectively with significant difference (Z=11.29,P<0.001). The 3-year overall survival rate of TA and TT groups was 69.2%(95%CI:64.1%-73.7%) and 55.8% (95%CI:44.8%-65.4%) respectively, which was not significantly different by log-rank test (P=0.059). However, the stage III subgroup analysis showed that the survival of TA group was better [the 3-year overall survival in TA group and TT group was 78.1%(95%CI:70.5-84.0) and 46.3%(95%CI:31.0-60.3) resepectively(P=0.001)]. Multivariate Cox regression analysis revealed that the TT group had poor survival outcome (HR=2.45,95%CI:1.30-4.64, P=0.006). CONCLUSION The overall survival outcomes in the TA group are better, especially in stage III patients, which may be associated with the higher metastatic rate of abdominal lymph node and the more complete lymphadenectomy via TA approach.
Adenocarcinoma ; classification ; mortality ; pathology ; surgery ; China ; Databases, Factual ; Esophageal Neoplasms ; classification ; pathology ; surgery ; Esophagectomy ; methods ; Esophagogastric Junction ; pathology ; surgery ; Gastrectomy ; methods ; Humans ; Laparotomy ; Lymph Node Excision ; methods ; Neoplasm Staging ; Retrospective Studies ; Stomach Neoplasms ; classification ; mortality ; pathology ; surgery ; Survival Analysis ; Thoracic Surgical Procedures

OBJECTIVETo establish the tissue response grading (TRG) system following neoadjuvant chemotherapy and to investigate its application in the gastric cancer patients who received neoadjuvant chemotherapy.

METHODSData of 30 cT3-4N0-3M0 gastric cancer cases who received neoadjuvant chemotherapy and operation from May 2017 to February 2018 at Department of Gastrointestinal Surgery, West China Hospital were analyzed retrospectively. The edema degree of gastrointestinal tract and perigastric tissues, intraoperative effusion, and fibrosis of tumor and lymph nodes bearing tissues which could be divided into 4 categories constituted the core parameters of the TRG system following neoadjuvant chemotherapy. Four categories of edema: grade 0, no obvious tissue edema; grade 1, slight tissue edema and swelling, no obvious effusion when dissecting the capsule of connective tissues; grade 2, moderate tissue edema and swelling, a few effusion when dissecting the capsule of connective tissues; grade 3, severe tissue edema and swelling with high tension on the capsule of connective tissues, tension blister could be observed in some patients, continuous effusion when dissecting the capsule of connective tissues. Four categories of intraoperative effusion: grade 0, no obvious effusion; grade 1, slight effusion and a few intraperitoneal exudation; grade 2, moderate effusion and continuous intraperitoneal exudation necessitating interrupted suction; grade 3, severe effusion and continuous intraperitoneal exudation necessitating constant suction. Four categories of fibrosis: grade 0, no fibrosis; grade 1, slight fibrosis with threadiness fibrous bands, clear dissecting space could be found between the fibrous tissues and adventitia/normal tissues; grade 2, moderate fibrosis with flaky fibrous tissues, the difficulty of tissue and lymph nodes dissection increased although dissecting space could be found between the fibrous tissues and adventitia/normal tissues; grade 3, severe fibrosis with hard and flaky fibrous membrane, the difficulty of tissue and lymph nodes dissection increased extremely and the fibrous tissues merges with adventitia/normal tissues without dissecting space. The relationships of TRG system with tumor response evaluation by computed tomography (CT), tumor regression score, surgical duration, number of retrieved lymph nodes, number of metastatic lymph nodes, number of enlarged lymph nodes seen in the preoperative CT scans as well as postoperative complications were analyzed using t test, χ² test and logistic regression model.

RESULTSNineteen male and 11 female patients with a mean age of(59.1±9.4) years were enrolled. There were 17 cases of grade 1, 12 cases of grade 2 and 1 case of grade 3 for tissue edema, while the corresponding number was 14, 15 and 1 for intraoperative effusion and 15, 14 and 1 for fibrosis respectively. There were no significant differences among the different degrees of tissue edema, intraoperative effusion and fibrosis in terms of the tumor response evaluation by CT and tumor regression score (all P>0.05). The results of logistics regression showed that tumor response evaluation by CT was related with the degree of tissue edema (P=0.012) and intraoperative effusion (P=0.007), rather than the degree of fibrosis (P=0.527). However, tumor regression score was not related with the degree of tissue edema(P=0.345), intraoperative effusion (P=0.159) and fibrosis (P=0.207). Surgical duration of one case with all grade 3 in tissue edema, intraoperative effusion and fibrosis was 408 minutes, which was longer than those with grade 1 and grade 2 patients [(295.9±40.1) minutes and (293.1±34.3) minutes, respectively]; the number of retrieved lymph nodes, metastatic lymph nodes, and enlarged lymph nodes seen in the preoperative CT scans of this case with all grade 3 were 25, 4 and 1, which were all less than those with grade 1 and grade 2 (42.3±11.9 and 38.5±18.2, 7.3±9.1 and 8.1±9.7, 1.8±1.6 and 2.3±1.3, respectively). There were no significant differences between grade 1 and grade 2 of tissue edema, intraoperative effusion and fibrosis in terms of surgical duration, retrieved lymph nodes, metastatic lymph nodes and enlarged lymph nodes seen in the preoperative CT scans(all P>0.05). Four patients suffered from pulmonary complications and 2 patients experienced slight lymphatic, and all leakage were cured by conservative therapies. There were no significant differences among the different grades of tissue edema, intraoperative effusion and fibrosis in terms of the operation-associated complications (all P>0.05).

CONCLUSIONThe tissue response grading system can assist the judgment of operation difficulty and reflect the effectiveness of neoadjuvant chemotherapy to some extent, which has the possibility of applications.

Aged ; China ; Female ; Humans ; Lymph Node Excision ; Lymph Nodes ; Male ; Middle Aged ; Neoadjuvant Therapy ; Retrospective Studies ; Stomach Neoplasms ; drug therapy ; surgery

Objective: To observe the cellular damage of low-dose combined exposure to Hg, Pb and Cd on hippocampal neurons in rat. Methods: SH-SY5Y cells were randomly divided into 8 groups by 2×2×2 factorial design: control group, Pb exposure group, Hg exposure group, Pb+Hg exposure group, Pb+Cd exposure group, Hg+Cd exposure group and Pb+Cd+Hg exposure group. And the cell viabilities were measured. On this basis, an animal model was established. Twenty eight-week-old SD pregnant rats were randomly divided into four groups by random number table, and five in each group: the control group(distilled water), 1-fold metal mixture exposure group (1×MM, poisoning solution containing mercury chloride 0.15 mg/L, lead acetate trihydrate 25 mg/L, cadmium chloride 7.5 mg/L), 5-fold metal mixture exposure group (5×MM, poisoning solution containing mercury chloride 0.75 mg/L, lead acetate trihydrate 125.00 mg/L, cadmium chloride 37.50 mg/L), 10-fold metal mixture exposure group (10×MM, poisoning solution containing mercury chloride 1.50 mg/L, lead acetate trihydrate 250.00 mg/L, cadmium chloride 75.00 mg/L). Pregnant rats drank water until delivery. Twenty male pups were selected and exposed to these metals through breast milk until weaned. The heavy metals dose of poisoning water was adjusted, and then the weaned rats were exposed to heavy metals via drinking poisoning water until adulthood (postnatal day 83). The blood samples and brain hippocampus samples were collected to observe the ultrastructural changes of hippocampus, and to determine the levels of Hg, Pb and Cd in blood. In addition, apoptosis rate and fluorescence intensity of reactive oxygen species and intracellular free calcium concentration ([Ca²⁺]_i) in hippocampal neurons were measured. Results: Cellular factorial design analysis showed that Hg+Pb+Cd (at no observed adverse effect level, 1.0, 0.5 and 0.1 μmol/L, respectively)had a interaction on cell viability after 48 or 72 hours of combined exposure (P<0.05). The results of ultrastructure showed that mitochondria decreased, ridges and matrixes gradually dissolved in rat hippocampal neurons of 5×MM group; nuclear chromatin aggregated, more ridges and matrixes dissolved and the mitochondria also decreased in rat hippocampal neurons of 10×MM group. The concentration of Hg, Pb and Cd in the blood of 1×MM group, 5×MM group and 10×MM group were higher than those in the control group, and the differences were statistically significant (P<0.001). There was no significant difference in apoptosis rate between the 1×MM group and the control group. The apoptosis rate of 5×MM group and 10×MM group was higher than that in the control group, and the differences were statistically significant (P<0.001). There was no statistically significant difference in the fluorescence intensity of reactive oxygen species in hippocampal neurons of the 1×MM group and the control group. The fluorescence intensity of reactive oxygen species in the 5×MM group and the 10×MM group was higher than that in the control group, the difference was statistically significant (P<0.05). There was no significant difference in the fluorescence intensity of [Ca²⁺]_i between the 1×MM group and the control group. The fluorescence intensity values of [Ca²⁺]_i in the 5×MM group and the 10×MM group were higher than the control group, the differences were statistically significant (P<0.001). Conclusion Low-level combined exposure to Hg, Pb, and Cd caused synergistic neurotoxic damage, and the process may be related to the changes of neuronal apoptosis, reactive oxide species, and [Ca²⁺]_i levels.