BACKGROUND:Previous studies have demonstrated that the cannabinoid type Ⅰ receptor can enhance the proliferation and neural differentiation of neural stem cells and mesenchymal stem cells.Moreover,cannabinoid type Ⅰ also governs the proliferation and mineralization capacity of human apical papilla stem cells.However,there are relatively few investigations concerning the impact of cannabinoid type Ⅰ overexpression on the neural differentiation of human apical papilla stem cells.OBJECTIVE:To investigate the effect of cannabinoid type Ⅰ on neural differentiation of human apical papilla stem cells in vitro.METHODS:Healthy third molars with immature root tips that need to be removed for orthodontic treatment were collected,and human apical papilla stem cells were isolated and cultured by tissue block method combined with enzyme digestion method.Cannabinoid type Ⅰ gene was introduced into human apical papilla stem cells by lentivirus-mediated transfection technique.A blank control group,a negative control group,and cannabinoid type Ⅰ overexpression group were set up.The transfection effect of overexpression of cannabinoid type Ⅰ lentivirus on human apical papilla stem cells was verified by Western Blot.The control group,negative control group,cannabinoid type Ⅰ overexpression group and cannabinoid type Ⅰ overexpression+AM251(cannabinoid type Ⅰ receptor antagonist)group were set up.Cell proliferation was detected by CCK-8 assay at 1,5,and 10 days after neural induction.On day 10 of neural induction,the expression levels of TH,NeuroD-1,and NCAM1 genes were detected by qRT-PCR,and the protein expression levels of Nestin and TUBB3 were detected by immunofluorescence.RESULTS AND CONCLUSION:(1)Compared with the blank control group and the negative control group,the expression of cannabinoid receptor Ⅰ protein in the cannabinoid receptor Ⅰ overexpression group was significantly increased,and the difference was significant(P＜0.05).(2)Compared with the blank control group and the negative control group,the proliferation ability of human apical papilla stem cells in the cannabinoid type Ⅰ overexpression group was the strongest at 5 and 10 days after neural induction(P＜0.05).(3)Compared with the blank control group and the negative control group,the mRNA expression of NeuroD-1,NCAM1,and TH in the stem cells of the human apical papilla in the cannabinoid type Ⅰ overexpression group was significantly increased,and the fluorescence intensity of Nestin and TUBB3 was significantly enhanced(P＜0.05).(4)Compared with the cannabinoid type Ⅰ overexpression group,the proliferation ability,mRNA expression level of NeuroD-1,NCAM1,and TH,as well as the fluorescence intensity of Nestin and TUBB3,were significantly decreased in the cannabinoid type Ⅰ overexpression+AM251 group(P＜0.05).These findings conclude that overexpression of cannabinoid type Ⅰ promoted the proliferation and neural differentiation of human apical dentin papilla stem cells.

BACKGROUND:Bone tissue loss caused by tumors and trauma can have an adverse effect on postoperative rehabilitation.Therefore,scaffold materials are usually implanted during treatment.However,the existing implant materials are relatively simple and lack antibacterial properties.Early implantation may lead to iatrogenic autoinfection and have an adverse effect on osteogenesis.OBJECTIVE:To construct a KR-12-a5 polypeptide-nanohydroxyapatite-small intestinal submucosa composite scaffold and evaluate its feasibility as a material for promoting bone defect repair.METHODS:The small intestinal submucosa scaffold and the small intestinal submucosa scaffold containing 25,50,and 100 mg/mL nanohydroxyapatite(referred to as nHA-SIS scaffold)were prepared by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride/N-hydroxysuccinimide cross-linking method.The appropriate scaffold was screened for subsequent experiments by mechanical property testing.The antibacterial properties of KR-12-a5 polypeptide solution against Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum were detected.The nHA-SIS scaffolds were immersed in 250,500,and 1 000 μg/mL KR-12-a5 peptide solutions for 24 hours,and then freeze-dried to obtain peptide-loaded nanohydroxyapatite-porcine small intestinal submucosa composite scaffolds(denoted as P-nHA-SIS scaffolds).The sustained-release properties of the three groups of scaffolds were characterized.The nHA-SIS scaffolds and the three groups of P-nHA-SIS scaffolds were co-cultured with Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum for 24 hours or 48 hours.The scaffolds with strong antibacterial ability were screened by live and dead bacteria staining and scanning electron microscopy for subsequent experiments.The degradation properties and water absorption rates of the uncross-linked small intestinal submucosa scaffolds,cross-linked small intestinal submucosa scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were characterized.The extracts of cross-linked small intestinal submucosal scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were co-cultured with MC3T3-E1 cells.CCK-8 assay and live-dead cell staining were performed.The effects of the extracts of the three scaffolds on the migration of MC3T3-E1 cells were detected by Transwell chamber assay.RESULTS AND CONCLUSION:(1)The elastic modulus and compressive strength of 25,50,and 100 mg/mL nHA-SIS scaffolds were higher than those of small intestinal submucosal scaffolds(P＜0.05),among which the elastic modulus and compressive strength of 25 mg/mL nHA-SIS scaffolds were the highest,and this group of scaffolds were selected for subsequent experiments to load peptides.(2)KR-12-a5 peptide had strong antibacterial activity against common bacteria in bone defects(Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum).The three groups of P-nHA-SIS scaffolds all had sustained release properties.With the increase of peptide mass concentration,the antibacterial property of P-nHA-SIS scaffold was enhanced.Among them,the P-nHA-SIS scaffold loaded with 500 μg/mL peptide had achieved a satisfactory antibacterial effect,and this group of scaffolds would be selected in the future.(3)The degradation rate of the three groups of cross-linked scaffolds was lower than that of the uncross-linked scaffolds,and the water absorption rate was greater than that of the uncross-linked scaffolds.P-nHA-SIS scaffolds could promote the proliferation and migration of MC3T3-E1 cells without affecting the activity of MC3T3-E1 cells.(4)The results show that P-nHA-SIS scaffolds have strong antibacterial properties and the ability to promote the proliferation and migration of MC3T3-E1 cells,and are expected to be used in bone defect repair.

BACKGROUND:The prevalence of osteoporosis is high in postmenopausal women,but muscle mass,grip strength,and how these factors affect osteoporosis are understudied,and the exact link between them has not been clarified.OBJECTIVE:To investigate the correlation between muscle mass,grip strength,appendicular skeletal muscle index and bone mineral density in postmenopausal women with osteoporosis and to assess the potential values of these indices in predicting and diagnosing postmenopausal osteoporosis.METHODS:Eighty-three postmenopausal women were collected from the outpatient clinic of the Third Affiliated Hospital of Guangzhou University of Chinese Medicine from February 2023 to January 2024.General data were collected.Bone mineral density was detected.T-value,muscle mass of each part,grip strength were recorded.The body mass index and appendicular skeletal muscle index were calculated.The patients were categorized into non-osteoporosis group(n=17)and postmenopausal osteoporosis group(n=66)according to T value and fracture history,and were statistically analyzed accordingly.RESULTS AND CONCLUSION:(1)The body mass,body mass index,bone mineral density of the overall lumbar spine,muscle mass and appendicular skeletal muscle index were higher in the non-osteoporosis group than the osteoporosis group(P＜0.05).(2)Muscle mass was positively correlated with bone mineral density of the overall lumbar spine and individual vertebrae(P＜0.05).(3)Multiple stepwise linear regression analysis showed that body mass and grip strength were linearly and positively correlated with muscle mass;body height and muscle mass were linearly and positively correlated with grip strength,and body mass was linearly and negatively correlated with grip strength.Body mass index was linearly and positively correlated with bone mineral density,and age was linearly and negatively correlated with bone mineral density.(4)Analysis by receiver operating characteristic curve showed that:muscle mass(the area under the curve,sensitivity,specificity and critical value of muscle mass were 0.744,76.50％,74.20％and 36.50 kg,respectively,with P=0.002)and appendicular skeletal muscle index(the area under the curve,sensitivity,specificity and critical value of appendicular skeletal muscle index were 0.739,82.40％,62.10％and 5.81 kg/m2,respectively,and P=0.002)had good predictive value for postmenopausal osteoporosis.To conclude,a reduction in muscle mass and appendicular skeletal muscle index can help to predict the risk of postmenopausal osteoporosis,and the possibility of osteoporosis should be taken into account in postmenopausal women when muscle mass is＜36.50 kg or appendicular skeletal muscle index is＜5.81 kg/m2,in order to prevent the occurrence of postmenopausal osteoporosis.

ObjectiveTo observe the effects of Yiqi Huoxue Jiedu formula（YHJF） on immune cell exhaustion in the spleen of septic mice and to explore and validate its potential intervention targets. MethodsMice were randomly divided into the sham-operated， model， low-dose YHJF（4.1 g·kg^-1）， and high-dose YHJF（8.2 g·kg^-1） groups. Except for the sham-operated group， a cecal ligation and puncture（CLP） procedure was performed to establish a mouse sepsis model. The treatment groups received oral administration of the corresponding doses， while the sham-operated and model groups received an equal volume of physiological saline. After the intervention， the 7-day survival rate of each group was recorded， and spleen samples were collected 72 h post-intervention， and the spleen index was calculated. Terminal deoxynucleotidyl transferase deoxyuridine triphosphate（dUTP） nick end labeling（TUNEL） staining was used to detect apoptosis in spleen cells. Enzyme-linked immunosorbent assay（ELISA） was performed to measure the levels of interleukin（IL）-4 and IL-10 in the serum. Transcriptomics and metabolomics were used to screen for differentially expressed genes（DEGs） and differential metabolites in the spleen， followed by bioinformatics analysis to identify key targets. Real-time quantitative polymerase chain reaction（Real-time PCR）， flow cytometry， and multiplex immunofluorescence were used to verify the expressions of key genes and proteins. ResultsThe high-dose YHJF group significantly improved the 7-day survival rate of septic mice（P0.05）. Compared with the sham-operated group， the model group showed a significant increase in apoptosis of spleen cells and a decrease in the spleen index at 72 h post-modeling， with markedly elevated peripheral serum IL-4 and IL-10 levels（P0.01）. Compared with the model group， the high-dose YHJF group showed a reduction in apoptosis of spleen cells， an increase in the spleen index， and a significant decrease in peripheral serum IL-4 and IL-10 levels（P0.05）. Spleen transcriptomics identified 255 DEGs between groups， potentially serving as intervention targets for YHJF. Gene Ontology（GO） enrichment analysis revealed that DEGs were mainly involved in biological processes such as natural killer（NK） cell-mediated positive immune regulation， cell killing， cytokine production， positive regulation of innate immune cells， and interferon production. Kyoto Encyclopedia of Genes and Genomes（KEGG） pathway enrichment analysis showed that DEGs were mainly involved in cytokine-cytokine receptor interactions， viral protein interactions with cytokines and cytokine receptors， chemokine signaling pathway， and nuclear transcription factor-κB（NF-κB） signaling pathway. Protein-protein interaction（PPI） network analysis identified CD160， granzyme B（GZMB）， and chemokine ligand 4（CCL4） as key targets for YHJF in treating sepsis. Metabolomics identified 46 differential metabolites that were significantly reversed by YHJF intervention， and combined transcriptomics and metabolomics analysis identified 17 differential metabolites closely related to CD160. Pathway enrichment revealed that these metabolites were mainly involved in glycerophospholipid metabolism， arachidonic acid metabolism， glycosylphosphatidylinositol（GPI） anchor biosynthesis， linoleic acid metabolism， and α-linolenic acid metabolism pathways. Verification results showed that， compared with the sham-operated group， the model group exhibited significantly elevated CD160 mRNA expression level in the spleen， along with markedly decreased CCL4 and GZMB mRNA expression， and had a significant increase in CD160 expression on the surface of natural killer T（NKT） cells in the spleen（P0.01）. Compared with the model group， the high-dose YHJF group had a significant decrease in CD160 mRNA expression in the spleen， a significant increase in CCL4 and GZMB mRNA expressions. Further flow cytometry and immunofluorescence revealed that compared with the sham-operated group， CD160 expression on the surface of splenic NKT cells in the model group was significantly increased（P0.01）， while high-dose YHJF intervention significantly reduced CD160 expression（P0.01）. ConclusionYHJF may alleviate NKT cell exhaustion in sepsis by downregulating the expression of the negative co-stimulatory molecule CD160， and this regulatory effect is closely related to fatty acid metabolism pathways. This study provides new insights and targets for further exploration of strengthening vital Qi and detoxifying strategy to improve immune cell exhaustion in acute deficiency syndrome of sepsis.

ObjectiveTo observe the effects of Yiqi Huoxue Jiedu formula（YHJF） on immune cell exhaustion in the spleen of septic mice and to explore and validate its potential intervention targets. MethodsMice were randomly divided into the sham-operated， model， low-dose YHJF（4.1 g·kg^-1）， and high-dose YHJF（8.2 g·kg^-1） groups. Except for the sham-operated group， a cecal ligation and puncture（CLP） procedure was performed to establish a mouse sepsis model. The treatment groups received oral administration of the corresponding doses， while the sham-operated and model groups received an equal volume of physiological saline. After the intervention， the 7-day survival rate of each group was recorded， and spleen samples were collected 72 h post-intervention， and the spleen index was calculated. Terminal deoxynucleotidyl transferase deoxyuridine triphosphate（dUTP） nick end labeling（TUNEL） staining was used to detect apoptosis in spleen cells. Enzyme-linked immunosorbent assay（ELISA） was performed to measure the levels of interleukin（IL）-4 and IL-10 in the serum. Transcriptomics and metabolomics were used to screen for differentially expressed genes（DEGs） and differential metabolites in the spleen， followed by bioinformatics analysis to identify key targets. Real-time quantitative polymerase chain reaction（Real-time PCR）， flow cytometry， and multiplex immunofluorescence were used to verify the expressions of key genes and proteins. ResultsThe high-dose YHJF group significantly improved the 7-day survival rate of septic mice（P0.05）. Compared with the sham-operated group， the model group showed a significant increase in apoptosis of spleen cells and a decrease in the spleen index at 72 h post-modeling， with markedly elevated peripheral serum IL-4 and IL-10 levels（P0.01）. Compared with the model group， the high-dose YHJF group showed a reduction in apoptosis of spleen cells， an increase in the spleen index， and a significant decrease in peripheral serum IL-4 and IL-10 levels（P0.05）. Spleen transcriptomics identified 255 DEGs between groups， potentially serving as intervention targets for YHJF. Gene Ontology（GO） enrichment analysis revealed that DEGs were mainly involved in biological processes such as natural killer（NK） cell-mediated positive immune regulation， cell killing， cytokine production， positive regulation of innate immune cells， and interferon production. Kyoto Encyclopedia of Genes and Genomes（KEGG） pathway enrichment analysis showed that DEGs were mainly involved in cytokine-cytokine receptor interactions， viral protein interactions with cytokines and cytokine receptors， chemokine signaling pathway， and nuclear transcription factor-κB（NF-κB） signaling pathway. Protein-protein interaction（PPI） network analysis identified CD160， granzyme B（GZMB）， and chemokine ligand 4（CCL4） as key targets for YHJF in treating sepsis. Metabolomics identified 46 differential metabolites that were significantly reversed by YHJF intervention， and combined transcriptomics and metabolomics analysis identified 17 differential metabolites closely related to CD160. Pathway enrichment revealed that these metabolites were mainly involved in glycerophospholipid metabolism， arachidonic acid metabolism， glycosylphosphatidylinositol（GPI） anchor biosynthesis， linoleic acid metabolism， and α-linolenic acid metabolism pathways. Verification results showed that， compared with the sham-operated group， the model group exhibited significantly elevated CD160 mRNA expression level in the spleen， along with markedly decreased CCL4 and GZMB mRNA expression， and had a significant increase in CD160 expression on the surface of natural killer T（NKT） cells in the spleen（P0.01）. Compared with the model group， the high-dose YHJF group had a significant decrease in CD160 mRNA expression in the spleen， a significant increase in CCL4 and GZMB mRNA expressions. Further flow cytometry and immunofluorescence revealed that compared with the sham-operated group， CD160 expression on the surface of splenic NKT cells in the model group was significantly increased（P0.01）， while high-dose YHJF intervention significantly reduced CD160 expression（P0.01）. ConclusionYHJF may alleviate NKT cell exhaustion in sepsis by downregulating the expression of the negative co-stimulatory molecule CD160， and this regulatory effect is closely related to fatty acid metabolism pathways. This study provides new insights and targets for further exploration of strengthening vital Qi and detoxifying strategy to improve immune cell exhaustion in acute deficiency syndrome of sepsis.

Attention deficit hyperactivity disorder （ADHD） is often accompanied by tic disorder. The core pathogenesis is considered to be ministerial fire scorching yin and internal stirring of deficient wind， which leads to disharmony between the body and spirit， resulting in clinical manifestations. The treatment principles emphasize nourishing yin fluids， calming ministerial fire， and extinguishing endogenous wind （内风）. The method of nourishing yin fluids is applied throughout the entire treatment process， commonly using ingredients such as Shudihuang （Rehmanniae Radix Praeparata）， Shanzhuyu （Corni Fructus）， Gouqizi （Lycii Fructus）， Wuweizi （Schisandrae Chinensis Fructus）， and Tusizi （Cuscutae Semen）. These are combined with approaches to harmonize the zang-fu organs， primarily including extinguishing liver wind， clearing heart fire， nourishing kidney water， and strengthening spleen earth， thereby stabilizing ministerial fire and extinguishing endogenous wind. Additionally， emotional regulation and smoothing emotional constraint are essential to improve clinical symptoms in children with ADHD comorbid with tic disorder.

ObjectiveThis study aims to elucidate the potential mechanism of Zuojinwan in improving liver fibrosis through hepatic tissue metabolomics analysis. MethodsTwenty-four mice were randomly allocated into normal group， model group ， positive drug group （silymarin， 100 mg·kg^-1）， and Zuojinwan group （Zuojinwan solution， 2.5 g·kg^-1）， with per group six mice. Liver fibrosis model was induced via intraperitoneal injection of olive oil solution with 10% carbon tetrachloride （CCl₄） （0.5 μL·g^-1， three times weekly for 8 weeks） in all groups except the normal group. During the final 4 weeks， the silymarin group received silymarin （100 mg·kg^-1） by gavage thrice weekly， while the Zuojinwan group was administered Zuojinwan solution （2.5 g·kg^-1） under the same regimen. After the last administration， the levels of liver fibrosis indicators and liver injury markers in serum were detected. The pathological morphological changes of the liver tissues were observed. The levels of liver fibrosis markers α-smooth muscle actin （α-SMA） and Collagen Ⅰ（ColⅠ） were detected. Metabolomics was analyzed on mice's liver tissues. The mice's serum was collected for metabolomics analysis. ResultsCompared with the model group， Zuojinwan significantly improved indicators related to liver fibrosis and liver injury. Compared with the normal group， the model group showed significantly elevated levels of fibrosis markers such as laminin （LN）， hyaluronic acid （HA）， procollagen typeⅢ （PC-Ⅲ）， and type Ⅳ Collagen （Ⅳ-C）， while liver injury indicators such as alanine aminotransferase （ALT）， aspartate aminotransferase （AST）， alkaline phosphatase （ALP）， lactate dehydrogenase （LDH）， and total bilirubin （TBIL）， exhibited a marked upward trend （P<0.05）. Compared with the model group， the silymarin group showed a significant decrease in the aforementioned indicators （P<0.05）. Notably， compared with the model group， the Zuojinwan group exhibited a significant reduction in all these indicators （P<0.05）， with efficacy comparable to that of the silymarin group. Zuojinwan reduced mRNA and protein levels of α-SMA and ColⅠ in the liver tissue. Metabolomics results revealed that compared with the model group， Zuojiinwan significantly reduced levels of glucose metabolism-related metabolites such as D-fructose 1，6-bisphosphate （FBP）， nicotinamide adenine dinucleotide phosphate （NADPH）， sodium beta-D-fructose 6-phosphate （F6P）， dihydroxyacetone phosphate （DHAP）， fumaric acid， and D-glucose 6-phosphate （G6P） （P<0.05）. Serum enzyme-linked immunosorbent assay （ELISA） was used to detect glucose metabolism indicators and further validate the regulatory effect of Zuojinwan on glucose metabolism. ConclusionThese results suggest that Zuojinwan may improve liver fibrosis by regulating the dysregulated levels of glucose metabolism during the progression of liver fibrosis.

Objective: To propose an improved method for constructing the internal quality control (IQC) framework for ELISA assays and validate its efficacy by statistically analyzing IQC data from nine blood center laboratories. Methods: 1) IQC data was collected from nine blood centers and analyzed using a domestic HBsAg ELISA detection kit as an example. 2) Differences between IQC values across batches within Blood Center 1 were assessed. 3) Statistical analyses were performed on batch usage, number of batches used, days of use, number of QC points, batch-specific means, and coefficients of variation (CV) across all nine centers. 4) Using the improved construction method for IQC framework, provisional and permanent frames were established for batches within Blood Center 1 and Blood Center 9, followed by outlier determination. Results: 1) Statistically significant differences were observed in IQC data between batches within Blood Center 1 (P<0.01). It is recommended that both the control material/reagents and the control chart framework be replaced simultaneously. 2) There were substantial differences among 9 blood centers regarding the control material/reagent lot numbers used, the number of QC runs per batch, and the QC values for identical lots. Therefore, individual laboratories should establish their own IQC chart frameworks. 3) The improved IQC framework construction method for ELISA assays is as follows: provisional frames are established via frame-shifting, using the pre-experimental mean and cumulative coefficient of variation (CV) from the preceding batch. For batches used >20 days with >20 QC points, permanent frames are constructed by aggregating in-control data accumulated over ≥20 days with ≥20 points to calculate cumulative mean and standard deviation. The provisional and permanent frames constructed by this method identified all 26 extreme outliers across Blood Centers 1 and 9 as out-of-control. Among the 218 general outliers, 10 were classified as normal by the provisional frames, while the remainder were designated as warnings or out-of-control. This method effectively monitors assay stability. Conclusion: Based on the statistical analysis of IQC practices across blood centers of varying scales, combined with the inherent characteristics of ELISA assays and the batch-to-batch instability of reagents/QC materials, it is recommended to reconstruct QC charts upon lot changes. The proposed method—utilizing frame-shifting for provisional frames and establishing permanent frames based on cumulative data—is applicable to blood center laboratories of differing sizes and effectively monitors the stability of the ELISA assay process.

Objective To quantitatively assess the exposure-response association between exposure to heatwave and sudden death, estimate the attributable excess deaths, and identify potential vulnerable subgroups. Methods A time-stratified case-crossover study was conducted among residents who died from sudden death in Jiangsu Province, China between 2015 and 2021. Heatwave events in Jiangsu Province, defined using varying relative temperature thresholds and durations, were identified using temperature data from the China Meteorological Administration Land Data Assimilation System (CLDAS V2.0). Individual heatwave exposure was assessed based on each subject's residential address. The exposure-response association between heatwave and sudden death was evaluated using conditional logistic regression model combined with a Distributed Lag Nonlinear Model(DLNM). Heatwave-attributable excess deaths were estimated. Stratified analyses by sex and age were performed to assess potential effect modifications. Results Under all definitions, exposure to heatwave was significantly associated with an increased risk of sudden death, and the risk increased with the intensity of heatwave. Using the P95_3d definition (temperature exceeding the 95th percentile for ≥3 consecutive days), heatwave was significantlyassociated with a 56% increased risk of sudden death (95% CI: 31%, 86%). The population-attributable fraction of sudden death due to heatwave exposure was 1.45% (95% CI: 0.97%, 1.90%). Stratified analyses indicated no statistically significant differences in the association between heatwave exposure and sudden death across age or sex subgroups. Conclusion Heatwave exposure was associated with an increased risk of sudden death. Reducing heatwave exposure during summer may help lower the occurrence of sudden death.

Objective To explore the effect of remote ischemic preconditioning (RIPC) on preoperative heart rate variability in patients with heart valves. Methods Patients scheduled to undergo on-pump cardiac valve surgery in the Department of Cardiovascular Surgery, General Hospital of Northern Theater Command, between January and July 2022 were initially enrolled. Eligible patients were randomly assigned at a 1 : 1 ratio to either the RIPC group or the control group. Relevant indicators of heart rate variability [standard deviation of NN interval (SDNN), standard deviation of mean value of NN interval in every five minutes (SDANN), mean square root of difference between consecutive NN intervals (RMSSD), percentage of adjacent RR interval>50 ms (PNN50), low frequency (LF) component, high frequency (HF) component and LF/HF] at 8 hours in the morning on the surgical day between two groups were compared. Results A total of 118 patients were initially assessed. After screening, 58 patients were excluded, and 60 patients provided written informed consent and were enrolled in the trial, with 30 allocated to the RIPC group and 30 to the control group. Seven patients in the control group and 5 patients in the RIPC group were subsequently excluded due to missing heart rate variability data resulting from cancelled operations. Finally, 23 patients in the control group and 25 patients in the RIPC group were included in the analysis. There was no statistical difference in baseline characteristics between the two groups, and there was no significant difference in heart rate variability 24 hours before intervention (P>0.05). After the intervention measures were taken, the comparison of the results of heart rate variability at 8 hours on the day of operation showed that SDNN and SDANN of patients in the RIPC group were higher than those in the control group, with statistical differences (P<0.05). Conclusion RIPC can stabilize the preoperative heart rate variability of patients undergoing cardiac valve surgery.