Objective:To analyze the efficacy of transjugular intrahepatic portosystemic shunt (TIPS) combined with main splenic artery embolization in the treatment of patients with portal hypertension upper gastrointestinal bleeding complicated with extensive portal vein thrombosis (PVT).Methods:This study was a prospective, single-center, open-label, single-arm clinical trial. In the first phase, 81 patients with portal hypertension upper gastrointestinal bleeding who were admitted to Beijing Shijitan Hospital, Capital Medical University from January 2018 to December 2018 were consecutively enrolled, including 57 males and 24 females, with the age of (51.3±10.4) years. During TIPS surgery, the pressure of the portal vein before and after the balloon blocking the splenic artery was measured to clarify the contribution of the splenic artery to portal hypertension. In the second stage, from January 2019 to December 2022, 104 patients with portal hypertension upper gastrointestinal bleeding complicated with extensive PVT were re-enrolled, including 71 males and 33 females, with the age of (50.9±12.5) years. TIPS combined with main splenic artery embolization was performed, and portal vein pressure was measured before and after embolization. Follow up on the postoperative esophageal and gastric varices of the patients in the second stage.Results:The portal vein pressures before and after the first stage of balloon occlusion of the splenic artery were (35.2±8.4) mmHg (1 mmHg=0.133 kPa) and (24.2±6.3) mmHg, respectively. The pressure after occlusion was lower than that before occlusion, and the difference was statistically significant ( t=10.54, P<0.001). The portal vein pressures before and after the second stage embolization were (36.1±9.5) mmHg and (21.1±4.7) mmHg respectively. The pressure after embolization was lower than that before embolization, and the difference was statistically significant ( t=13.47, P<0.001). In the second stage, among the 104 patients, the proportion of those whose varicose veins disappeared or improved 6 months after the operation was 43.3%(45/104) and 51.0%(53/104), respectively. There were no patients with aggravation or rebleeding due to rupture. One year later, 8 patients (7.7%) had aggravated or ruptured esophageal and gastric varices with bleeding. Two years later, 12 patients (11.5%) had aggravated or bleeding. Conclusion:TIPS combined with main splenic artery embolization can effectively reduce the portal vein pressure in patients with portal hypertension upper gastrointestinal bleeding complicated with extensive PVT, improve the degree of esophageal and gastric varices, and reduce the risk of gastrointestinal bleeding.

Objective To investigate the effects of electroacupuncture for the restoration of muscle regeneration and the secretion of exosomes around acupoints in a model of erector spinae muscle injury.Methods Forty SPF-grade male SD rats were randomly divided into blank group,model group,electroacupuncture group,and electroacupuncture+exosome inhibitor group,with 10 rats per group.Except for the blank group,the erector spinae muscle injury models were established in other groups by intramuscular injection of 0.5%bupivacaine.The blank control group received no treatment,whereas the rats in the electroacupuncture and electroacupuncture+exosome inhibitor groups were treated with electroacupuncture at"Weizhong"(BL40)and"Shenshu"(BL23)acupoints,respectively,stimulation was applied daily for 7 consecutive days,with each session lasting 20 minutes.The parameters used were a sparse-dense wave waveform,a frequency of 2/10 Hz,and a current intensity of 1 mA.The exosome inhibitor GW4869(3 g/L,50 μL per acupoint)was injected 1 h before each electroacupuncture in the electroacupuncture+exosome inhibitor group.After intervention,the erector spinae muscles were collected and observed by HE and Masson staining for morphological changes.The expression of paired box gene 7(Pax7)and recombinant myogenic differentiation(MyoD)was detected by immunohistochemistry,while the expression of myogenin(MyoG)and myosin heavy chain(MyHC)proteins was detected by western blotting.The serum exosomes of rats in each group were extracted and identified by transmission electron microscopy and nanoparticle tracking analysis,and the expression of Alix,differentiation cluster 63(CD63),and tumor susceptibility gene 101(TSG101)proteins were detected by Western blotting.Results Compared with the blank group,the model group,the electroacupuncture group,and the electroacupuncture+exosome inhibitor group exhibited spinae muscle fiber fragmentation,degeneration,necrosis,and inflammatory cell infiltration in HE staining.The result of Masson staining showed that collagen fiber hyperplasia was increased.The model group showed increased expression of MyoD,Pax7,MyoG,MyHC,and CD63,while TSG101 expression was downregulated(P<0.05).In the electroacupuncture group,the expression of MyoD,Pax7,Alix,and TSG101 was elevated(P<0.05),and the expression of MyHC and CD63 was decreased(P<0.05).The electroacupuncture+exosome inhibitor group displayed increased expression of MyHC,Alix,and TSG101(P<0.05),and the expression of CD63 was decreased(P<0.05).Compared with the model group,the electroacupuncture group and the electroacupuncture+exosome inhibitor group showed reduced muscle fiber degeneration,necrotic areas,and inflammatory cell infiltration as observed in HE staining,along with decreased collagen fiber hyperplasia in Masson staining.Specifically,the electroacupuncture group demonstrated increased expression of MyoD,Pax7,MyoG,Alix,and TSG101(P<0.05),and the expression of CD63 was decreased(P<0.05).The electroacupuncture+exosome inhibitor group displayed downregulated expression of Pax7,MyoG,MyHC,and CD63(P<0.05),and the expression of Alix and TSG101 was regulated(P<0.05).Compared with the electroacupuncture+exosome inhibitor group,the electroacupuncture group exhibited less muscle fiber degeneration and necrosis,reduced inflammatory cell infiltration in HE staining,and decreased stained collagen fibers in Masson staining.The electroacupuncture group showed increased expression of MyoD,Pax7,MyoG,MyHC,Alix,and CD63(P<0.05).Conclusion Electroacupuncture can up-regulate the expression of Pax7 and MyoD,and promote the regeneration of erector spinae muscles,which may be related to stimulating the secretion of exosomes around the acupoint.Exosomes may be an important mediator for the efficacy of acupuncture.

Objective To investigate the effects of electroacupuncture for the restoration of muscle regeneration and the secretion of exosomes around acupoints in a model of erector spinae muscle injury.Methods Forty SPF-grade male SD rats were randomly divided into blank group,model group,electroacupuncture group,and electroacupuncture+exosome inhibitor group,with 10 rats per group.Except for the blank group,the erector spinae muscle injury models were established in other groups by intramuscular injection of 0.5%bupivacaine.The blank control group received no treatment,whereas the rats in the electroacupuncture and electroacupuncture+exosome inhibitor groups were treated with electroacupuncture at"Weizhong"(BL40)and"Shenshu"(BL23)acupoints,respectively,stimulation was applied daily for 7 consecutive days,with each session lasting 20 minutes.The parameters used were a sparse-dense wave waveform,a frequency of 2/10 Hz,and a current intensity of 1 mA.The exosome inhibitor GW4869(3 g/L,50 μL per acupoint)was injected 1 h before each electroacupuncture in the electroacupuncture+exosome inhibitor group.After intervention,the erector spinae muscles were collected and observed by HE and Masson staining for morphological changes.The expression of paired box gene 7(Pax7)and recombinant myogenic differentiation(MyoD)was detected by immunohistochemistry,while the expression of myogenin(MyoG)and myosin heavy chain(MyHC)proteins was detected by western blotting.The serum exosomes of rats in each group were extracted and identified by transmission electron microscopy and nanoparticle tracking analysis,and the expression of Alix,differentiation cluster 63(CD63),and tumor susceptibility gene 101(TSG101)proteins were detected by Western blotting.Results Compared with the blank group,the model group,the electroacupuncture group,and the electroacupuncture+exosome inhibitor group exhibited spinae muscle fiber fragmentation,degeneration,necrosis,and inflammatory cell infiltration in HE staining.The result of Masson staining showed that collagen fiber hyperplasia was increased.The model group showed increased expression of MyoD,Pax7,MyoG,MyHC,and CD63,while TSG101 expression was downregulated(P<0.05).In the electroacupuncture group,the expression of MyoD,Pax7,Alix,and TSG101 was elevated(P<0.05),and the expression of MyHC and CD63 was decreased(P<0.05).The electroacupuncture+exosome inhibitor group displayed increased expression of MyHC,Alix,and TSG101(P<0.05),and the expression of CD63 was decreased(P<0.05).Compared with the model group,the electroacupuncture group and the electroacupuncture+exosome inhibitor group showed reduced muscle fiber degeneration,necrotic areas,and inflammatory cell infiltration as observed in HE staining,along with decreased collagen fiber hyperplasia in Masson staining.Specifically,the electroacupuncture group demonstrated increased expression of MyoD,Pax7,MyoG,Alix,and TSG101(P<0.05),and the expression of CD63 was decreased(P<0.05).The electroacupuncture+exosome inhibitor group displayed downregulated expression of Pax7,MyoG,MyHC,and CD63(P<0.05),and the expression of Alix and TSG101 was regulated(P<0.05).Compared with the electroacupuncture+exosome inhibitor group,the electroacupuncture group exhibited less muscle fiber degeneration and necrosis,reduced inflammatory cell infiltration in HE staining,and decreased stained collagen fibers in Masson staining.The electroacupuncture group showed increased expression of MyoD,Pax7,MyoG,MyHC,Alix,and CD63(P<0.05).Conclusion Electroacupuncture can up-regulate the expression of Pax7 and MyoD,and promote the regeneration of erector spinae muscles,which may be related to stimulating the secretion of exosomes around the acupoint.Exosomes may be an important mediator for the efficacy of acupuncture.

Objective:To analyze the efficacy of transjugular intrahepatic portosystemic shunt (TIPS) combined with main splenic artery embolization in the treatment of patients with portal hypertension upper gastrointestinal bleeding complicated with extensive portal vein thrombosis (PVT).Methods:This study was a prospective, single-center, open-label, single-arm clinical trial. In the first phase, 81 patients with portal hypertension upper gastrointestinal bleeding who were admitted to Beijing Shijitan Hospital, Capital Medical University from January 2018 to December 2018 were consecutively enrolled, including 57 males and 24 females, with the age of (51.3±10.4) years. During TIPS surgery, the pressure of the portal vein before and after the balloon blocking the splenic artery was measured to clarify the contribution of the splenic artery to portal hypertension. In the second stage, from January 2019 to December 2022, 104 patients with portal hypertension upper gastrointestinal bleeding complicated with extensive PVT were re-enrolled, including 71 males and 33 females, with the age of (50.9±12.5) years. TIPS combined with main splenic artery embolization was performed, and portal vein pressure was measured before and after embolization. Follow up on the postoperative esophageal and gastric varices of the patients in the second stage.Results:The portal vein pressures before and after the first stage of balloon occlusion of the splenic artery were (35.2±8.4) mmHg (1 mmHg=0.133 kPa) and (24.2±6.3) mmHg, respectively. The pressure after occlusion was lower than that before occlusion, and the difference was statistically significant ( t=10.54, P<0.001). The portal vein pressures before and after the second stage embolization were (36.1±9.5) mmHg and (21.1±4.7) mmHg respectively. The pressure after embolization was lower than that before embolization, and the difference was statistically significant ( t=13.47, P<0.001). In the second stage, among the 104 patients, the proportion of those whose varicose veins disappeared or improved 6 months after the operation was 43.3%(45/104) and 51.0%(53/104), respectively. There were no patients with aggravation or rebleeding due to rupture. One year later, 8 patients (7.7%) had aggravated or ruptured esophageal and gastric varices with bleeding. Two years later, 12 patients (11.5%) had aggravated or bleeding. Conclusion:TIPS combined with main splenic artery embolization can effectively reduce the portal vein pressure in patients with portal hypertension upper gastrointestinal bleeding complicated with extensive PVT, improve the degree of esophageal and gastric varices, and reduce the risk of gastrointestinal bleeding.

Patients with severe trauma require an extremely timely treatment and transfusion plays an irreplaceable role in the emergency treatment of such patients. An increasing number of evidence-based medicinal evidences and clinical practices suggest that patients with severe traumatic bleeding benefit from early transfusion of low-titer group O whole blood or hemostatic resuscitation with red blood cells, plasma and platelet of a balanced ratio. However, the current domestic mode of blood supply cannot fully meet the requirements of timely and effective blood transfusion for emergency treatment of patients with severe trauma in clinical practice. In order to solve the key problems in blood supply and blood transfusion strategies for emergency treatment of severe trauma, Branch of Clinical Transfusion Medicine of Chinese Medical Association, Group for Trauma Emergency Care and Multiple Injuries of Trauma Branch of Chinese Medical Association, Young Scholar Group of Disaster Medicine Branch of Chinese Medical Association organized domestic experts of blood transfusion medicine and trauma treatment to jointly formulate Chinese expert consensus on blood support mode and blood transfusion strategies for emergency treatment of severe trauma patients ( version 2024). Based on the evidence-based medical evidence and Delphi method of expert consultation and voting, 10 recommendations were put forward from two aspects of blood support mode and transfusion strategies, aiming to provide a reference for transfusion resuscitation in the emergency treatment of severe trauma and further improve the success rate of treatment of patients with severe trauma.

Objective To optimize the screening methods for antiallergic activity of two Chinese medicines in vitro and compare the antiallergic activity of five medicine pairs in vitro.Methods The degranulation assay of RBL-2H3 cells was optimized,and the activity of the five drugs on inhibiting mast cell degranulation was compared by toluidine blue staining and the release of β-HEX and histamine(HIS).The hyaluronidase inhibition test was optimized to compare the hyaluronidase inhibition effect of five Chinese medicine pairs.Results In the experiment of degranulation of RBL-2H3 cells,5 medicine pairs could inhibit β-HEX release from model cells to different degrees(P<0.05),including Schizonepetae Herba-Saposhnicovia divaricata,Ephedrae Herba-Asarum,Saposhnicovia divaricata-Radix Angelicae dahuricae,Rhizoma Chuanxiong-Asarum.The β-HEX release rate in the supernatant of degranulated model cells was significantly increased(P<0.05)after coculture with Flos Magnoliae-Fructus Xanthii.All the five medicine pairs could reduce HIS release in the supernatant of degranulated model cells.In the hyaluronase inhibition rate test,the hyaluronase inhibition rate of each medicine pair was Rhizoma Chuanxion-Asarum>Saposhnicovia divaricate-Radix Angelicae dahuricae>Schizonepetae Herba-Saposhnicovia divaricate>Ephedrae Herba-Asarum,among which Rhizoma Chuanxiong-Asarum had the strongest anti-allergic activity.Conclusion The trend of antiallergic activity of different drugs obtained by the two methods is consistent in vitro,indicating that the two methods can be used for screening antiallergic activity in vitro.

ObjectiveTo explore the therapeutic effect and mechanism of the Danhe granules on hypercholesterolemia rats by observing the changes in the efficacy indicators and the levels of proteins related to the cholesterol metabolism pathway in the rats under the intervention of Danhe granules. MethodSD rats were randomly assigned to either the blank group or the model group based on their body weight. The blank group had normal chow diets， while the model group was fed high-fat diets for seven weeks. One week after the establishment of the model， the content of the serum total cholesterol （TC） in the model rats was detected. According to the TC value， the model group was further randomly divided into a control group， pravastatin sodium tablet group（4.02 mg·kg^-1）， Xuezhikang capsule group（0.12 g·kg^-1）， high-dose， middle-dose， and low-dose groups of Danhe granules（4.536， 2.268， 1.134 g·kg^-1）. After grouping the model groups， each treatment group received continuous oral gavage for six weeks， with weekly measurements of body weight and food intake （the difference between feed intake and feed surplus）. Six weeks later， the levels of serum TC， triglyceride （TG）， low-density lipoprotein cholesterol （LDL-C）， and high-density lipoprotein cholesterol （HDL-C） were measured. The liver pathology and lipid droplet distribution were evaluated by hematoxylin-eosin （HE） staining and oil red O staining， with scoring and calculation conducted. Rat liver tissue was collected， and western blot and immunohistochemistry （IHC） were used to detect the expression levels of cholesterol metabolism-related proteins namely phosphorylated adenosine 5'-monophosphate （AMP）-activated protein kinase （p-AMPK）， AMPK， 3-hydroxy-3-methyl glutaryl coenzyme A reductase （HMGCR）， low-density lipoprotein receptor （LDLR）， cholesterol 7α-hydroxylase （CYP7A1）， Acyl-coenzyme A： cholesterol acyltransferase 2 （ACAT2）， and apolipoprotein B （ApoB） in hypercholesterolemia rats. ResultCompared with the blank group， the model group showed a significantly higher level of serum TC （P<0.01）. The TG level had no significant change， and the HDL-C level was significantly decreased （P<0.05）. The liver index， steatosis score， total score of pathological state， and the positive area ratio of oil red O staining were significantly increased （P<0.01）， and the protein expression levels of p-AMPK， p-AMPK/AMPK， LDLR， and CYP7A1 were significantly decreased （P<0.05， P<0.01）， while the protein expression levels of AMPK， HMGCR， and ACAT2 were significantly increased （P<0.05， P<0.01）. Compared with the model group， the TC level in each dose group of Danhe granules was significantly decreased （P<0.05）， and the positive area ratio of oil red O staining in the pravastatin sodium tablet group and medium-dose group of Danhe granules was significantly decreased （P<0.05）. In each administration group， the protein expression levels of p-AMPK and p-AMPK/AMPK were significantly increased （P<0.05， P<0.01）， and the levels of HMGCR and ACAT2 were significantly decreased （P<0.01）. The ApoB level showed a downward trend. The CYP7A1 level in the pravastatin sodium tablet group and each dose group of Danhe granules was significantly increased （P<0.05， P<0.01）， and the LDLR level in the pravastatin sodium tablet group， Xuezhikang capsule group， and high-dose and medium-dose groups of Danhe granules was significantly increased （P<0.05， P<0.01）. ConclusionDanhe granules can reduce serum TC levels and improve hepatic steatosis. It may activate AMPK， down-regulate the expression of HMGCR， and inhibit cholesterol synthesis. It can also up-regulate the expression of LDLR and CYP7A1， promote cholesterol uptake and excretion， down-regulate the expression of ACAT2 and ApoB， reduce cholesterol absorption and assembly of LDL and other lipoproteins， and thus play a role in the treatment of hypercholesterolemia.

BACKGROUND:It is of great significance to find new diagnostic markers of the disease and molecular targets for the treatment of the disease and the alleviation of organ injury.Ferroptosis is a newly discovered form of cell death.Overactivation of ferroptosis in animal models of sepsis is associated with the activation of inflammatory response and the injury of the liver,heart,kidney and other important organs,but the relationship between ferroptosis and bloodstream infection is not very clear. OBJECTIVE:To study the changes and biological significance of ferroptosis in a mouse model of blood stream infection induced by different bacteria. METHODS:Blood stream infection models induced by gram negative bacteria Escherichia coli,Klebsiella pneumoniae and gram positive bacteria Staphylococcus aureus and Enterococcus faecalis were established in SPF-grade ICR male mice,with 42 mice in each group.The mRNA expression levels of ferroptosis marker genes transferrin receptor 1 and glutathione peroxidase 4 in the liver,myocardium and kidney were detected at 0.5,1,3,6,12,24 and 48 hours after modeling.Another 18 SPF-grade ICR male mice were selected and randomly divided into dimethyl sulfoxide(DMSO)control group,DMSO+Klebsiella pneumoniae group,and Ferrostatin-1+Klebsiella pneumoniae group,with 6 mice in each group.In the latter two groups,animal models of Klebsiella pneumoniae bloodstream infection were established by tail vein injection of Klebsiella pneumoniae suspension,and 5 mg/kg Ferrostatin-1 and an equal dose of DMSO were given intraperitoneally 1 hour prior to the modeling of bloodstream infection,respectively.Serum levels of alanine aminotransferase,aspartate aminotransferase,blood creatinine,blood urea nitrogen,phosphocreatine kinase isoenzyme,lactate dehydrogenase,and mRNA expression levels of ferroptosis marker genes in various tissues were assayed at 6 hours after modeling. RESULTS AND CONCLUSION:After bloodstream infection modeling,the mRNA expression levels of transferrin receptor 1 in the liver,myocardium and kidney of bloodstream infection mice with different bacteria increased first and then decreased;and the mRNA expression level of glutathione peroxidase 4 decreased first,then increased,and reached the peak at 6 hours after modeling.The changes in transferrin receptor 1 and glutathione peroxidase 4 mRNA levels in bloodstream infection mice induced by gram-negative bacteria were more significant than those in blood stream infection mice induced by gram-positive bacteria,especially in bloodstream infection mice induced by Klebsiella pneumoniae.At 6 hours after bloodstream infection induced by Klebsiella pneumoniae,the levels of alanine aminotransferase,aspartate aminotransferase,serum creatinine,blood urea nitrogen,creatine phosphate kinase isoenzyme,lactate dehydrogenase in mice were significantly increased.Before modeling,Ferrostatin-1 intervention significantly reduced the levels of alanine aminotransferase,aspartate aminotransferase,serum creatinine,blood urea nitrogen,creatine phosphate kinase isoenzyme,and lactate dehydrogenase.All these findings indicate that the activation of ferroptosis in bloodstream infection mice induced by different bacteria is obvious,and the activation of ferroptosis in bloodstream infection mice induced by gram-negative bacteria is more obvious.Inhibition of iron death significantly attenuates liver,myocardial,and kidney injury in the mouse model of bloodstream infection induced by Klebsiella pneumoniae.

Objective To investigate the mechanism of morin-induced autophagy in non-small cell lung cancer A549 cells based on mTOR/STAT3 signaling axis.Methods A549 cells were divided into blank group and 30,60,90,120 and 150 μg·mL-1 of morin groups.After 24,48 and 72 hours of culture,the cell proliferation activity was detected by CCK-8 method,and the cell inhibition rate was calculated.A549 cells were divided into blank group and 30,90,150 μg·mL-1 morin groups.After 14 days of culture,the cell proliferation was detected by colony formation assay.After 24 hours of culture,the cell proliferation ability was detected by BeyoClickTM EdU-488.Apoptosis was detected by flow cytometry;acridine orange staining was used to detect cell autophagy;the formation of autophagosomes was observed by transmission electron microscopy.Western Blot was used to detect the expression levels of apoptosis,autophagy and mTOR/STAT3 signaling axis-related proteins in cells.A549 cells were divided into blank group,blank group + chloroquine(10 μg·mL-1)group,morin(30,150 μg·mL-1)group,morin(30,150 μg·mL-1)+ chloroquine(10 μg·mL-1)group.After 48 hours of intervention,the cell activity was detected by CCK-8 method,and the cell survival rate was calculated.Results Compared with the blank group,the inhibition rate of A549 cells in 60,90,120,150 μ g·mL-1 of morin group was significantly increased after 24 hours of intervention(P＜0.05,P＜0.001).The inhibition rates of A549 cells in 30,60,90,120 and 150 μg·mL-1 of morin groups were significantly increased after 48 and 72 hours of intervention(P＜0.001).The number of A549 cell colonies and the number of green fluorescent proliferation positive cells in the 30,90,150 μg·mL-1 of morin groups were significantly decreased(P＜0.01,P＜0.001),the apoptosis rate was significantly increased(P＜0.01,P＜0.001),and the protein expression level of cleaved-PARP was significantly increased(P＜0.001).The protein expression levels of p-P38/P38 MAPK in A549 cells of 90 and 150 μg·mL-1 of morin groups were significantly increased(P＜0.01,P＜0.001).Different degrees of orange fluorescence appeared in A549 cells of 30,90 and 150 μg·mL-1 of morin groups,and the orange fluorescence of 90 and 150 μg·mL-1 of morin groups was significant.Autophagosomes and autolysosomes appeared in the cytoplasm of A549 cells in 150 μg·mL-1 of morin group,respectively.The protein expression of LC3-Ⅱ in A549 cells of 150 μg·mL-1 of morin group was significantly up-regulated(P＜0.05).The protein expression of Atg16L1-Ⅱ in A549 cells of 90,150 μg·mL-1 of morin group was significantly up-regulated(P＜0.001),and the protein expressions of p-mTOR/mTOR and p-STAT3/STAT3 were significantly down-regulated(P＜0.001).Compared with the morin(150 μg·mL-1)group,the survival rate of A549 cells in the morin(150 μg·mL-1)+chloroquine(10 μg·mL-1)group was significantly increased(P＜0.05).Conclusion Morin can promote the apoptosis of A549 cells and induce autophagy in A549 cells,and the mechanism may be related to mTOR/STAT3 axis.

Objective:To investigate the association of exposure to PM 2.5 and its constituents during pregnancy and fetal growth and to further identify critical windows of exposure for fetal growth. Methods:We included 4 089 mother-child pairs from the Jiangsu Birth Cohort Study between January 2016 and October 2019. Data of general characteristics, clinical information, daily average PM 2.5 exposure, and its constituents during pregnancy were collected. Fetal growth parameters, including head circumference (HC), abdominal circumference (AC), and femur length (FL), were measured by ultrasound after 20 weeks of gestation, and then estimated fetal weight (EFW) was calculated. Generalized linear mixed models were adopted to examine the associations of prenatal exposure to PM 2.5 and its constituents with fetal growth. Distributed lag nonlinear models were used to identify critical exposure windows for each outcome. Results:A 10 μg/m 3 increase in PM 2.5 exposure during pregnancy was associated with a decrease of 0.025 ( β=-0.025, 95% CI: -0.048- -0.001) in HC Z-score, 0.026 ( β=-0.026, 95% CI: -0.049- -0.003) in AC Z-score, and 0.028 ( β=-0.028, 95% CI:-0.052--0.004) in EFW Z-score, along with an increased risk of 8.5% ( RR=1.085, 95% CI: 1.010-1.165) and 13.5% ( RR=1.135, 95% CI: 1.016-1.268) for undergrowth of HC and EFW, respectively. Regarding PM 2.5 constituents, prenatal exposure to black carbon, organic matter, nitrate, sulfate (SO 42-) and ammonium consistently correlated with decreased HC Z-score. SO 42- exposure was also associated with decreased FL Z-scores. In addition, we found that gestational weeks 2-5 were critical windows for HC, weeks 4-13 and 19-40 for AC, weeks 4-13 and 23-37 for FL, and weeks 4-12 and 20-40 for EFW. Conclusions:Our findings demonstrated that exposure to PM 2.5 and its constituents during pregnancy could adversely affect fetal growth and the critical windows for different fetal growth parameters are not completely consistent.