Objective:To evaluate the role of fibrinogen in perioperative neurocognitive disorder (PND) in aged mice.Methods:Sixty SPF healthy male C57BL/6J mice, aged 16-18 months, weighing 25-30 g, were divided into 4 groups ( n=15 each) using a random number table method: control group (group C), PND group (group P), urokinase group (group U) and PND+ urokinase group (group PU). Abdominal surgery was performed under 3% sevoflurane anesthesia to establish the mouse model of PND. In PU group, urokinase 20 000 U/kg was intraperitoneally administered at 1 h after surgery, once a day, for 5 consecutive days. In group U, urokinase was intraperitoneally injected once a day for 5 consecutive days without anesthesia and surgery. The cognitive function was assessed after operation using the novel object recognition test (discrimination index) and the Morris water maze test (frequency of crossing the original platform and percentage of the time spent in the target quadrant). The expression of occludin, claudin-5, fibrinogen and ionized calcium-binding adapter molecule 1 (Iba-1) and CD11b in hippocampal tissues was detected using Western blot, the area of fibrinogen extravascular deposits was measured and the morphology of microglia was observed using the immunofluorescence staining, and the mRNA expression of pro-inflammatory factors (interleukin-1beta, tumor necrosis factor-alpha, and inducible nitric oxide synthase), anti-inflammatory factors (interleukin-4 and arginase-1), and chemokines (chemokine 2 and chemokine ligand 10) in hippocampal tissues was detected by quantitative real-time polymerase chain reaction after surgery. Results:Compared with group C, the parameters of cognitive function were significantly decreased, the expression of occludin and claudin-5 was down-regulated, the expression of fibrinogen was up-regulated, the area of fibrinogen extravascular deposits was increased, the number of branches was decreased and the average process length was shortened in the microglia around fibrinogen deposits, the expression of Iba-1 and CD11b was up-regulated, the mRNA expression of proinflammatory cytokines and chemokines was up-regulated, and the mRNA expression of the anti-inflammatory factors was down-regulated in group PND ( P<0.05). Compared with group PND, the parameters of cognitive function were significantly increased, the expression of occludin and claudin-5 was up-regulated, the expression of fibrinogen was down-regulated, the area of fibrinogen extravascular deposits was decreased, the number of branches was increased and the average process length was prolonged in the microglia around fibrinogen deposits, the expression of Iba-1 and CD11b was down-regulated, the mRNA expression of proinflammatory cytokines and chemokines was down-regulated, and the mRNA expression of the anti-inflammatory factors was up-regulated in group PU ( P<0.05). Conclusions:Fibrinogen deposits in the brain parenchyma through the damaged blood-brain barrier after anesthesia and surgery and participates in the development of PND, and the underlying mechanism may be related to the promotion of microglial activation and the induction of neuroinflammation in aged mice.

Objective:To evaluate the relationship between the mechanism of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) preventing sevoflurane-induced neurotoxicity and phosphorylated Tau glymphatic system clearance pathway in neonatal mice.Methods:Eighteen C57BL/6 pregnant mice were used in this study and subjected to 2 feeding regiments using the random number table method. Twelve mice were selected to receive a standard diet, and 6 mice were selected to receive a diet supplemented with fish oil (ω-3 polyunsaturated fatty acids [300 mg was added to every 20 g of standard diet from the 2nd day of gestation to 14 days after parturition). The healthy neonatal mice of both sexes, aged 6 days, weighing 3-5 g, were selected after parturition. Forty-eight neonatal pups from 6 pregnant mice that were fed a standard diet were assigned to control group (C group), 48 neonatal pups from 6 pregnant mice that were fed a standard diet were assigned to sevoflurane group (S group), and 48 neonatal pups from pregnant mice that were fed a diet supplemented with fish oil were assigned to ω-3 PUFAs plus sevoflurane group (PS group) using the random number table method. All the offspring mice in all groups were breastfed until 21 days of birth and then were housed in separate cages from their mothers after 21 days of birth and provided with ad libitum access to standard food. S group and PS group inhaled 3% sevoflurane and 40% oxygen for 2 h daily on postnatal days 6, 7 and 8. C group inhaled only 40% oxygen at the same flow rate. Y maze test was performed at postnatal day 33 to assess the spatial memory and cognitive function. The rotarod test was performed at postnatal day 35 to assess the fine motor coordination. The influx and efflux functions of the glymphatic system were assessed through intracisternal tracer infusion with the fluorescent tracer at postnatal days 14 and 35. The influx function was evaluated by the percentage of the area of tracer penetration 30 min after injection, while the efflux function was determined by the percentage of the residual area of the tracer 90 min after injection. The mice were sacrificed and the hippocampal tissue was obtained at postnatal day 14 for determination of the expression of phosphorylated Tau protein at serine 202 site and threonine 205 site (Tau-PS202/PT205) and total Tau protein by Western blot. The cerebrospinal fluid (CSF) was collected at postnatal day 14 for determination of the concentration of phosphorylated Tau protein by enzyme-linked immunosorbent assay. The mice were sacrificed and the hippocampal tissue was obtained at postnatal day 35 for determination of the expression of caspase-3, caspase-9 and cytochrome C (Cyt c) (by Western blot) and the apoptosis rate of neurons (by TUNEL).Results:Compared with C group, the time of staying at the new arm and in the rotarod test was significantly shortened, the percentage of new arm movement distance was decreased, the percentage of tracer penetration area was decreased at postnatal day 14, the percentage of residual tracer area was increased at postnatal day 14, the expression of Tau-PS202/PT205 in the hippocampus was up-regulated at postnatal day 14, the concentration of phosphorylated Tau protein in CSF was reduced at postnatal day 14, the apoptosis rate of hippocampal neurons was increased at postnatal day 35 ( P<0.05), and the expression of caspase-3, caspase-9 and Cyt c in the hippocampus was up-regulated at postnatal day 35 in S group ( P<0.05). Compared with S group, the time of staying at the new arm and in the rotarod test was significantly prolonged, the percentage of new arm movement distance was increased, the percentage of tracer penetration area was increased at postnatal day 14, the percentage of residual tracer area was decreased at postnatal day 14, the expression of Tau-PS202/PT205 in the hippocampus was down-regulated at postnatal day 14, the concentration of phosphorylated Tau protein in CSF was increased at postnatal day 14, the apoptosis rate of hippocampal neurons was decreased at postnatal day 35, and the expression of caspase-3, caspase-9 and Cyt c in the hippocampus was down-regulated at postnatal day 35 in PS group ( P<0.05). Conclusions:The mechanism by which ω-3 PUFAs prevents cerebral neurotoxicity induced by repeated neonatal sevofurane exposure may be related to the enhancement of phosphorylated Tau protein clearance via the glymphatic system.

Objective:To evaluate the relationship between the mechanism of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) in preventing brain neurotoxicity caused by multiple sevoflurane anesthesia and peroxisome proliferator-activated receptor gamma (PPARγ)/peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) signaling pathway in neonatal mice.Methods:This study was performed in 2 parts. Part Ⅰ Using a random number table method, 6 C57BL/6 pregnant mice were assigned to receive a standard diet, 3 pregnant mice were assigned to receive a diet supplemented with fish oil from day 2 of gestation to day 14 after parturition (ω-3 PUFAs 300 mg were added to every 20 g of conventional diet). Healthy C57BL/6 mice of both sexes, aged 6 days, weighing 3-5 g, were selected after parturition. Seventeen neonatal pups from 3 pregnant mice that were fed a conventional diet were assigned to control group (C group), 17 neonatal pups from 3 pregnant mice that were fed a conventional diet were assigned to sevoflurane group (S group), and 17 neonatal pups from pregnant mice that were fed a diet supplemented with fish oil were assigned to ω-3 PUFAs plus sevoflurane group (PS1 group) using the random number table method. Part Ⅱ Four C57BL/6 pregnant mice were assigned to receive a diet supplemented with fish oil from day 2 of gestation to day 14 after parturition. After parturition, 12 neonatal pups from 2 pregnant mice that were fed a diet supplemented with fish oil were assigned to ω-3 PUFAs plus sevoflurane group (PS2 group), and 12 neonatal pups from 2 pregnant mice that were fed a diet supplemented with fish oil were assigned to ω-3 PUFAs plus PPARγ inhibitor GW9662 plus sevoflurane group (PGS group) using a random number table method. GW9662 (2 mg/kg) was intraperitoneally injected at 30 min before exposure to sevoflurane in PGS group. All offspring mice were breastfed until 21 days of age, after which they were housed separately from the mother and allowed ad libitum access to a conventional diet. S, PS1, PS2 and PGS groups inhaled 3% sevoflurane in 40% oxygen for 2 h daily on postnatal days 6, 7 and 8. C group inhaled only 40% oxygen instead. Y maze test was performed on days 33 after birth. The rotarod test was performed on day 35 after birth. After the behavioral testing, the expression of PPARγ, PGC1α, mitofusin-1 (MFN1), MFN2, dynamin-related protein 1 (DRP1), interleukin-6 (IL-6), interleukin-1 β (IL-1 β), and tumor necrosis factor-α (TNF-α) was detected by Western blot, the ultrastructure of mitochondria in hippocampal neurons was observed with a transmission electron microscope, and the mitochondrial membrane potential (MMP), level of reactive oxygen species (ROS) and content of ATP were determined.Results:Part Ⅰ Compared with C group, the time of stay at the new-arm and time spent on the rotarod were significantly shortened, the percentage of movement distance in the new-arm was decreased, the expression of PPARγ, PGC1α, MFN1 and MFN2 in the hippocampus was down-regulated, the expression of DRP1, IL-6, IL-1β and TNF-α in the hippocampus was up-regulated, the MMP and content of ATP were decreased, and the level of ROS was increased in S group ( P<0.05). Compared with S group, the time of stay at the new-arm and time spent on the rotarod were significantly prolonged, the percentage of movement distance in the new-arm was increased, the expression of PPARγ, PGC1α, MFN1 and MFN2 in the hippocampus was up-regulated, the expression of DRP1, IL-6, IL-1β and TNF-α in the hippocampus was down-regulated, the MMP and content of ATP were increased, and the level of ROS was decreased in PS1 group ( P<0.05). Part Ⅱ Compared with PS2 group, the time of stay at the new-arm and time spent on the rotarod were significantly shortened, the percentage of movement distance in the new-arm was decreased, the MMP and content of ATP were decreased, the level of ROS was increased, and the expression of IL-6, IL-1β and TNF-α was up-regulated ( P<0.05). Conclusions:The mechanism by which ω-3 PUFAs prevent brain neurotoxicity caused by multiple sevoflurane anesthesia is related to the activation of the PPARγ/PGC1α signaling pathway and alleviation of mitochondrial dysfunction and neuroinflammation in neonatal mice.

Objective:To evaluate the role of docosahexaenoic acid (DHA) in long-term cognitive impairment after multiple sevoflurane anesthesia in newborn mice.Methods:Clean-grade healthy male C57BL/6 mice, aged 6 days, were used in this study. Ten mice were divided into 2 groups ( n=5 each) by the random number table method: control group (group C) and sevoflurane group (group S). The animals inhaled 3% sevoflurane for 2 h at 6, 7 and 8 days after birth. The DHA content was detected by ultra-high performance liquid chromatography-mass spectrometry at 9 days of age. Fifty-two mice were selected and divided into 4 groups ( n=13 each) by a random number table method: control+ normal saline group (group C+ S), sevoflurane anesthesia + normal saline group (group S+ S), control+ DHA group (group C+ D), and sevoflurane anesthesia+ DHA group (group S+ D). The sevoflurane anesthesia method was the same as the one mentioned above. DHA 50 mg/kg was administered by intragastric gavage from postnatal days 6-19 (at 6, 7 and 8 days after birth, 2 h before anesthesia) in C+ D and S+ D groups. The equal volume of normal saline was given instead in C+ S group and S+ S group. The novel object recognition test was conducted at 37 days of age, and the Morris water maze test was performed at 42 days of age. The corpus callosum and hippocampal tissues were isolated at 47 days of age for examination of the ultrastructure of myelin (with a transmission electron microscope) and for determination of the expression of myelin basic protein (MBP) in hippocampal tissues (by Western blot). The G-ratio was calculated. Results:Compared with group C, the content of DHA in hippocampal tissues was significantly decreased in group S ( P<0.05). Compared with group C+ S, the discrimination index was significantly decreased, the percentage of duration of staying at the target platform quadrant and the number of crossing the original platform were decreased, the expression of MBP was down-regulated, and the G-ratio in the original platform and hippocampus was increased in S+ S group ( P<0.05). Compared with group S+ S, the discrimination index was significantly increased, the percentage of duration of staying at the target platform quadrant and the number of crossing the original platform were increased, the expression of MBP was up-regulated, and the G-ratio in the original platform and hippocampus was decreased in S+ D group ( P<0.05). Conclusions:The mechanism of long-term cognitive impairment following multiple sevoflurane anesthesia may be related to a decrease in the content of DHA, which subsequently leads to myelin structural damage in neonatal mice.

Objective:To evaluate the effect of multiple sevoflurane anesthesia on the metabolism of long-chain fatty acids in the hippocampus of newborn mice and the role of peroxisome proliferator-activated receptor-beta (PPARβ).Methods:Clean-grade healthy male C57BL/6 mice, aged 6 days, weighing 3-5 g, were divided into 2 groups ( n=8 each) by a random number table method: control group (group C) and multiple sevoflurane anesthesia group (group S). This study was performed in 2 parts. PartⅠ Sixteen newborn mice were divided into 2 groups ( n=8 each) using a random number table: control group (C group) and multiple sevoflurane anesthesia group (S group). Anesthesia was performed with sevoflurane on postnatal days 6, 7 and 8. The hippocampus was obtained at postnatal day 9 for determination of the content of long-chain fatty acids (by ultra-high performance liquid mass spectrometry), expression of PPARβ (by Western blot), and expression of stearoyl-CoA desaturase-2 (Scd2) and fatty acid desaturase 2 (Fads2) mRNA (using quantitative real-time polymerase chain reaction). Part Ⅱ Twenty-one newborn mice were divided into 3 groups ( n=7 each) using a random number table: control+ normal saline group (group C+ S), sevoflurane + normal saline group (group S+ S), and sevoflurane+ PPARβ specific agonist KD3010 group (group S+ K). Anesthesia was carried out with sevoflurane on postnatal days 6, 7 and 8. KD3010 25 mg/kg was intraperitoneally injected once a day from postnatal day 6 to 13 in S+ K group. The novel object recognition test was performed on postnatal day 37, and the Morris water maze test was performed on postnatal day 42. The hippocampal tissues were obtained on postnatal day 47 for detection of the expression of Scd2 mRNA and Fads2 mRNA by fluorescent quantitative real-time polymerase chain reaction. Anesthesia was carried out with sevoflurane as follows: Mice were exposed to 3% sevoflurane in 40% oxygen-60% nitrogen in an induction chamber for 2 h at a flow rate of 1 L/min. Results:PartⅠ Compared with group C, the total content of long-chain fatty acids, contents of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids were significantly decreased, the percentage of saturated fatty acids was increased, the percentage of monounsaturated fatty acids and polyunsaturated fatty acids was decreased, the expression of Scd2 mRNA and Fads2 mRNA was down-regulated, and the expression of PPARβ was down-regulated in group S ( P<0.05). Part Ⅱ Compared with group C+ S, the discrimination index in the novel object recognition test and percentage of time spent in the target quadrant were significantly decreased, the number of crossing the original platform was reduced, and the expression of Scd2 and Fads2 mRNA was down-regulated in group S+ S ( P<0.05). Compared with group S+ S, the discrimination index in the novel object recognition test and percentage of time spent in the target quadrant were significantly increased, the number of crossing the original platform was increased, and the expression of Scd2 and Fads2 mRNA was up-regulated in group S+ K ( P<0.05). Conclusions:Multiple anesthesia with sevoflurane can lead to the disorder of long-chain fatty acid metabolism in the hippocampus of neonatal mice, resulting in long-term cognitive dysfunction. The mechanism may be related to inhibiting the activity of hippocampal PPARβ signaling pathway.

Objective:To investigate the characteristics of the endometrial microbiota in patients with varying degrees of intrauterine adhesion (IUA).Methods:This single-center cross-sectional observational study enrolled 115 patients with IUA who were treated at the Hysteroscopic Center of Fuxing Hospital, Capital Medical University, from May 2022 to October 2023. After quality control and data preprocessing, 81 samples met the inclusion criteria for analysis. Patients were grouped according to an established IUA scoring and grading system into mild IUA ( n=38) and moderate-to-severe IUA ( n=43). Endometrial tissue was collected under sterile conditions. Bacterial genomic DNA was extracted, the 16S rRNA V3-V4 region was amplified, and sequencing was performed on an Illumina platform. Differences in endometrial microbiota diversity and composition were compared between the two groups. Results:Patients with varying degrees of IUA exhibited comparable species richness, evenness and diversity of endometrial microbiota. At the phylum level, the endometrial microbiota across all subjects was predominantly composed of Proteobacteria, Firmicutes, Cyanobacteriota, Bacteroidota, and Actinobacteriota, with Proteobacteria (32.29%) and Firmicutes (23.82%) showing the highest mean relative abundances. At the genus level, Ralstonia (16.67%), Lactobacillus (13.45%), and Streptococcus (7.07%) were the most abundant genera. Group comparisons showed that the abundance of Ralstonia was higher in the mild IUA group, whereas Lactobacillus, Vibrio and Pseudoalteromonas were more abundant in the moderate-to-severe IUA group; however, these differences did not reach statistical significance (all P>0.05). LEfSe analysis further indicated that Lactobacillus, Vibrio, Pseudoalteromonas, Aeromonas, Ureaplasma and Acetobacterium were relatively enriched in the moderate-to-severe IUA group, while Geobacillus, Stomatobaculum and Fusicatenibacter were more abundant in the mild IUA group. Conclusion:The composition of the endometrial microbiota differs among patients with varying IUA severity. IUA progression may be associated with alterations in the endometrial microbiota; however, causal relationships and underlying mechanisms require further investigation.

Currently, the performance of D2 lymphadenectomy for locally advanced gastric cancer (LAGC) has become an established therapeutic consensus. The accumulating evidence supporting the application of laparoscopic techniques in such procedures signifies the transition of laparoscopic radical gastrectomy from an exploratory phase into mature clinical practice, with the surgical volume showing a yearly increasing trend. Alongside advancements in imaging equipment, innovations in surgical instrument, and updates in therapeutic concepts, surgeons are placing increasing emphasis on the radicality of the operation, the quality of lymph node dissection, and perioperative safety. Lymph node dissection in the supra-pancreatic area along the celiac arterial system constitutes a critical step in radical gastrectomy for gastric cancer. Supra-pancreatic area serves not only as a major lymphatic drainage hub for the stomach but also presents significant surgical challenges due to its complex anatomy, difficult exposure, high risk of bleeding, and injury to vital structures traversing the area. Therefore, how to effectively reduce the difficulty for the assistant to expose, optimize the surgeon's control over the anatomical planes in this region, achieve more refined maneuvers, and consequently reduce bleeding, lower complication rates, and shorten operative time are core issues currently concerning surgeons. This article, based on author's clinical experience, aims to provide an in-depth discussion on the strategies for supra-pancreatic lymph node dissection in laparoscopic gastric cancer surgery.

Objective:To investigate the current talent cultivation among young pediatricians, and to provide insights for fostering a virtuous cycle in their education, scientific research, and career growth.Methods:This study enrolled 152 young pediatricians (under 45 years of age) who had completed or were participating in standardized residency training at the Children's Hospital of Soochow University since September 2014. The pediatricians were surveyed on clinical training, scientific research process, career development planning, policies, and incentive mechanisms using a self-administered questionnaire. SPSS 23.0 was used for statistical analysis. Enumeration data, expressed as the number of cases and composition ratios, were analyzed using chi-square tests, while ordinal data were analyzed using rank sum tests. The SPSS macroprogram PROCESS v3.3 was used for mediating effect analysis.Results:The results of the questionnaire survey of 152 respondents were as follows: 65.79% (100/152) were aged 25-34 years; 57.24% (87/152) held a master's degree; 13.82% (21/152), 16.45% (25/152), and 69.74% (106/152) held deputy senior professional titles and above, intermediate professional titles, and junior professional titles and below, respectively. More than half of the respondents desired expanded training in professional skill updates, scientific research capacity enhancement, and simulation teaching. The current training system was deemed simplistic in content and method, requiring optimization. The frequency of clinical teaching activities ( P<0.001), training methods ( P<0.001), and departmental mentorship atmosphere ( P<0.001) were correlated with the degree of satisfaction with clinical training. Among the respondents, 81.58% (124/152) reported insufficient time, energy, and motivation for scientific research. The frequency of training ( P<0.001), participation frequency ( P<0.001), diversity of training methods ( P=0.024), departmental mentorship atmosphere ( P<0.001), opportunities for collaboration ( P<0.001), and training in methodology and innovative thinking ( P=0.042) were correlated with the degree of satisfaction with the scientific research capability enhancement training. Notably, there was a marginally significant difference in degree of satisfaction with scientific research training among young physicians with different titles ( P=0.053). Only 38.16% (58/152) of the respondents had established mid-to-long-term career plans, indicating a lack of career planning awareness. Age ( P=0.001), educational background ( P=0.009), professional titles ( P=0.001), and completion status of standardized residency training ( P=0.011) were correlated with degree of satisfaction with career development planning. The departmental mentorship atmosphere ( P=0.013) and flexible work arrangements ( P=0.039) were correlated with degree of satisfaction with policies and incentive mechanisms, with a marginal significance for performance-based reward system ( P=0.057). The frequency of clinical training ( P=0.030) and scientific research training ( P=0.010) had a significant indirect mediating effect on the degree of satisfaction with clinical training through the departmental mentorship atmosphere. Conclusions:Optimizing the development pathway for young physicians requires improvements in clinical training system, scientific research management, career planning guidance, and overall supportive environment.

Objective:To investigate the characteristics of the endometrial microbiota in patients with varying degrees of intrauterine adhesion (IUA).Methods:This single-center cross-sectional observational study enrolled 115 patients with IUA who were treated at the Hysteroscopic Center of Fuxing Hospital, Capital Medical University, from May 2022 to October 2023. After quality control and data preprocessing, 81 samples met the inclusion criteria for analysis. Patients were grouped according to an established IUA scoring and grading system into mild IUA ( n=38) and moderate-to-severe IUA ( n=43). Endometrial tissue was collected under sterile conditions. Bacterial genomic DNA was extracted, the 16S rRNA V3-V4 region was amplified, and sequencing was performed on an Illumina platform. Differences in endometrial microbiota diversity and composition were compared between the two groups. Results:Patients with varying degrees of IUA exhibited comparable species richness, evenness and diversity of endometrial microbiota. At the phylum level, the endometrial microbiota across all subjects was predominantly composed of Proteobacteria, Firmicutes, Cyanobacteriota, Bacteroidota, and Actinobacteriota, with Proteobacteria (32.29%) and Firmicutes (23.82%) showing the highest mean relative abundances. At the genus level, Ralstonia (16.67%), Lactobacillus (13.45%), and Streptococcus (7.07%) were the most abundant genera. Group comparisons showed that the abundance of Ralstonia was higher in the mild IUA group, whereas Lactobacillus, Vibrio and Pseudoalteromonas were more abundant in the moderate-to-severe IUA group; however, these differences did not reach statistical significance (all P>0.05). LEfSe analysis further indicated that Lactobacillus, Vibrio, Pseudoalteromonas, Aeromonas, Ureaplasma and Acetobacterium were relatively enriched in the moderate-to-severe IUA group, while Geobacillus, Stomatobaculum and Fusicatenibacter were more abundant in the mild IUA group. Conclusion:The composition of the endometrial microbiota differs among patients with varying IUA severity. IUA progression may be associated with alterations in the endometrial microbiota; however, causal relationships and underlying mechanisms require further investigation.

Objective:To evaluate the role of fibrinogen in perioperative neurocognitive disorder (PND) in aged mice.Methods:Sixty SPF healthy male C57BL/6J mice, aged 16-18 months, weighing 25-30 g, were divided into 4 groups ( n=15 each) using a random number table method: control group (group C), PND group (group P), urokinase group (group U) and PND+ urokinase group (group PU). Abdominal surgery was performed under 3% sevoflurane anesthesia to establish the mouse model of PND. In PU group, urokinase 20 000 U/kg was intraperitoneally administered at 1 h after surgery, once a day, for 5 consecutive days. In group U, urokinase was intraperitoneally injected once a day for 5 consecutive days without anesthesia and surgery. The cognitive function was assessed after operation using the novel object recognition test (discrimination index) and the Morris water maze test (frequency of crossing the original platform and percentage of the time spent in the target quadrant). The expression of occludin, claudin-5, fibrinogen and ionized calcium-binding adapter molecule 1 (Iba-1) and CD11b in hippocampal tissues was detected using Western blot, the area of fibrinogen extravascular deposits was measured and the morphology of microglia was observed using the immunofluorescence staining, and the mRNA expression of pro-inflammatory factors (interleukin-1beta, tumor necrosis factor-alpha, and inducible nitric oxide synthase), anti-inflammatory factors (interleukin-4 and arginase-1), and chemokines (chemokine 2 and chemokine ligand 10) in hippocampal tissues was detected by quantitative real-time polymerase chain reaction after surgery. Results:Compared with group C, the parameters of cognitive function were significantly decreased, the expression of occludin and claudin-5 was down-regulated, the expression of fibrinogen was up-regulated, the area of fibrinogen extravascular deposits was increased, the number of branches was decreased and the average process length was shortened in the microglia around fibrinogen deposits, the expression of Iba-1 and CD11b was up-regulated, the mRNA expression of proinflammatory cytokines and chemokines was up-regulated, and the mRNA expression of the anti-inflammatory factors was down-regulated in group PND ( P<0.05). Compared with group PND, the parameters of cognitive function were significantly increased, the expression of occludin and claudin-5 was up-regulated, the expression of fibrinogen was down-regulated, the area of fibrinogen extravascular deposits was decreased, the number of branches was increased and the average process length was prolonged in the microglia around fibrinogen deposits, the expression of Iba-1 and CD11b was down-regulated, the mRNA expression of proinflammatory cytokines and chemokines was down-regulated, and the mRNA expression of the anti-inflammatory factors was up-regulated in group PU ( P<0.05). Conclusions:Fibrinogen deposits in the brain parenchyma through the damaged blood-brain barrier after anesthesia and surgery and participates in the development of PND, and the underlying mechanism may be related to the promotion of microglial activation and the induction of neuroinflammation in aged mice.