BACKGROUND:Scholars at home and abroad consider New Zealand rabbits to be an ideal model animal because of the similar anatomical morphology of the lumbar spine to that of the human lumbar spine.There is a lack of systematic comparison of different ways to establish rabbit intervertebral disc degeneration models under X-ray guidance. OBJECTIVE:To establish a rabbit model of lumbar disc degeneration using X-ray guided acupuncture,end-plate injection and combined method,and to compare the modeling effects of these three methods. METHODS:Eighteen 6-month-old New Zealand white rabbits were randomly selected and divided into four groups:acupuncture group,endplate injection group,combined group and blank control group.In the acupuncture group,three consecutive segments of the intervertebral discs(L2/3,L3/4,L4/5)were needled and modeled;in the endplate injection group,50 μL of anhydrous ethanol was injected at a single point on the endplates of the three consecutive segmental discs;in the combined group,three consecutive segmental intervertebral discs were needled and injected with 50 μL of anhydrous ethanol at four azimuthal points on the endplates of the corresponding segmental discs;and the blank control group received no interventions.X-ray examination was performed to measure the disc height index at 2,4,and 8 weeks after surgery.The intervertebral disc tissues were then taken for anatomical observation and pathological examination. RESULTS AND CONCLUSION:(1)Anatomical examination showed that fibrous annulus rupture,nucleus pulposus degeneration,and total disc structure disorder were the main manifestation in the acupuncture group,endplate injection group,and combined group,respectively.(2)X-ray examination showed that the disc height index showed the most obvious reduction in the acupuncture group at 2 weeks after operation,significant reductions in the endplate injection group at 2 and 4 weeks after operation,and significant reductions in the combined group at 2,4,and 8 weeks after operation.(3)Pathological examination showed that the fibrous ring structure was damaged and the inner annulus fibrosus protruded inward in the acupuncture group;endplate fissure,disordered arrangement and nucleus loss were observed in the endplate injection group;total disc structure disorder with the nucleus pulposus losing water and shrinking and no obvious border with the broken annulus fibrosus was found in the combined group.To conclude,acupuncture,endplate injection and the modified endplate injection method can establish the rabbit intervertebral disc degeneration model.Compared with the single method,the modified endplate injection method can greatly accelerate and aggravate the degeneration of the intervertebral disc,and can effectively shorten the experiment period.

BACKGROUND:Nerve growth factor is a protein that induces nerve growth and regulates biological behaviors such as proliferation and differentiation of mesenchymal stem cells. OBJECTIVE:To investigate the promoting effect of nerve growth factor on chondrogenic differentiation of bone marrow mesenchymal stem cells. METHODS:Rabbit bone marrow mesenchymal stem cells were isolated and cultured,and nerve growth factor was transfected into bone marrow mesenchymal stem cells by lentiviral transfection.The effects of nerve growth factor on the proliferation,migration,hypertrophic differentiation,and chondrogenic differentiation of bone marrow mesenchymal stem cells were detected by CCK-8 assay,cell scratch assay,alizarin red staining,and western blot assay,using the transfected null-loaded virus as control.To further investigate the promoting effect of nerve growth factor on the chondrogenic differentiation of bone marrow mesenchymal stem cells,interleukin 1β was added in bone marrow mesenchymal stem cells transfected with empty virus and nerve growth factor for 14 days.The expression of proteins related to chondrogenic differentiation and hypertrophic differentiation was detected by western blot assay. RESULTS AND CONCLUSION:(1)CCK-8 assay results showed that nerve growth factor had no significant effect on the proliferation of bone marrow mesenchymal stem cells.(2)Compared with the control group,overexpression of nerve growth factor enhanced the migration ability of the cells,and the expression of cartilage-associated proteins type II collagen and SOX9 was up-regulated(P<0.05),while the expression of hypertrophic-associated proteins type X collagen and Runx2 was down-regulated(P<0.05).(3)Compared with the empty virus+interleukin 1β group,the expression of cartilage-associated proteins type II collagen and Sox9 was up-regulated(P<0.05),and the expression of hypertrophy-associated proteins type X collagen and Runx2 was down-regulated after overexpression of nerve growth factor(P<0.05).(4)The results indicated that nerve growth factor could promote the chondrogenic differentiation of bone marrow mesenchymal stem cells.

Background Unhealthy lifestyle behaviors may be associated with an increased risk of cardiometabolic risk factor aggregation (CMRF≥ 2), and few studies have focused on the correlation between the two in occupational populations. Objective To investigate the current status of CMRF≥2 and the compliance of healthy lifestyle in male occupational personnel, explore the effect of lifestyle on cardiometabolic risk, and provide reference for formulating healthy behavior promotion strategies and reducing cardiometabolic risk in occupational populations. Methods The study subjects were selected from male workers who completed occupational health examinations at an occupational disease prevention and control hospital in Shanxi Province from May to December 2023, and 15125 study subjects aged 18−60 years were finally included according to pre-determined inclusion and exclusion criteria. All subjects received a series of assessments including questionnaires (basic information, lifestyle habits, and occupational factors), physical examination, laboratory tests, and six cardiometabolic risk factors (central obesity, hypertension, type 2 diabetes, hypertriglyceridemia, low-density lipoprotein cholesterolemia, and hyperuricemia). A healthy lifestyle score was calculated based on six behavioral factors (smoking, drinking, physical activity, diet, sleep, sedentary behavior) and 1 point for one positive healthy behavior. The enrolled workers were then divided into three groups according to their total scores: 0−1 points (poor group), 2−3 points (moderate group), and 4−6 points (good group). Logistic regression models were used to analyze the statistical associations between lifestyle and CMRF≥2. Results The median age of the 15125 male study participants was 40 years, and the positive rate of CMRF≥2 was 53.5%. Adherence to moderate alcohol consumption was the most compliant healthy behavior (79.4%), followed by current non-smoking (41.7%), while adherence to adequate sedentary behavior (23.6%) and healthy eating (21.1%) were relatively low, and only 17.4% were able to adhere to four or more healthy lifestyle behaviors. After adjusting for confounders, when compared with the poor group high lifestyle score was found to be a protective factor for CMRF≥2 (moderate group: OR=0.70, 95%CI: 0.63, 0.77; good group: OR=0.66, 95%CI: 0.58, 0.75). In stratified analyses across different job types (coal miners, auxiliary workers, ground workers, and others), occupational stress (with or without), shift patterns (day shift, night shift, or rotating shift), dust exposure (with or without), and noise exposure (with or without), individuals with higher lifestyle scores exhibited a consistently lower risk of CMRF≥2. There was an interaction between shift pattern and lifestyle on CMRF≥2 (P_interaction<0.05). Conclusion This occupational group has a high positive rate of CMRF≥2 and a high prevalence of poor lifestyles with low adherence to some healthy behaviors. High healthy lifestyle scores are associated with a lower risk of aggregation of cardiometabolic risk factors, which may be reduced through lifestyle interventions.

ObjectiveTo investigate the role of silent information regulatory protein （SIRT6）/hypoxia-inducible factor-1α （HIF-1α） pathway in regulating the reprogramming of glucose metabolism in ulcerative colitis （UC） and the mechanism of intervention of Shaoyaotang. MethodsForty-eight c57bL/6 mice were randomly divided into a blank group， a model group， a Mesalazine group （0.42 g·kg^-1）， a Shaoyaotang group （31.08 g·kg^-1）， an inhibitor group （OSS-128167， 50 mg·kg^-1）， and an inhibitor + Shaoyaotang group （50 mg·kg^-1 OSS-128167 + 31.08 g·kg^-1 Shaoyaotang）. A UC model was established by the administration of 2.5% dextran sulfate sodium （DSS） solution for mice in other groups for 7 d， except for the blank group. The mice in each group were treated with saline， Mesalazine， Shaoyaotang， inhibitor， and inhibitor + Shaoyaotang， respectively， for 7 d. The mice were necropsied 24 h after the last administration of the drug. The blood was collected from the orbital region， and colon tissue was taken. Hematoxylin-eosin （HE） staining was used to observe the pathological changes in colon tissue. Enzyme-linked immunosorbent assay （ELISA） was employed to detect serum interleukin （IL）-10， IL-17， and IL-6 levels. A biochemical method was used to detect glucose and lactate dehydrogenase A （LDHA） levels. Immunohistochemistry （IHC） was employed to detect IL-22 and transforming growth factor-β₁ （TGF-β₁） levels in colon tissue， and Western blot and real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） were used to detect relative protein and mRNA expressions of SIRT6， HIF-1α， and LDHA. ResultsCompared with those of the blank group， disease activity index （DAI） scores of mice in the model group and inhibitor group were significantly increased （P<0.01）. The length of colon tissue was significantly shortened， and colon tissue was congested and eroded. The pathohistological scores were significantly increased （P<0.01）. The levels of serum inflammatory factors IL-17 and IL-6 were significantly elevated， and the levels of IL-10 were significantly decreased （P<0.01）. The protein expressions of IL-22 and TGF-β₁ were significantly reduced in colon tissue （P<0.01）. The relative protein and mRNA expressions of SIRT6 were significantly decreased （P<0.01）， and the relative protein and mRNA expressions of HIF-1α and LDHA and the contents of glucose and lactate were significantly elevated （P<0.01）. The level of inflammation in the colon of the mice in the inhibitor group was more severe than that in the model group （P<0.01）. Compared with the model group， the Mesalazine group， the Shaoyaotang group， and the inhibitor + Shaoyaotang group showed reduced colonic injury， significant decrease in serum IL-17 and IL-6， significant increase in IL-10 （P<0.01）， significant increase in the protein expressions of IL-22 and TGF-β₁ in colon tissue （P<0.01）， significant increase in the protein expressions of SIRT6 and the relative mRNA expressions （P<0.01）， and significant reduction in the protein expressions of HIF-1α and LDHA， the relative mRNA expressions， and the contents of glucose and lactate （P<0.01）. Compared with those in the Shaoyaotang group， the serum IL-17 and IL-6 were significantly increased， and IL-10 was significantly decreased in the inhibitor + Shaoyaotang group （P<0.01）. The protein expressions of IL-22 and TGF-β₁ in colon tissue were significantly decreased （P<0.01）. The expressions of SIRT6 protein and the relative mRNA expressions were significantly decreased （P<0.01）. The protein expressions of HIF-1α and LDHA， the relative mRNA expressions， and the contents of glucose and lactate were significantly elevated （P<0.01）. However， the difference between the Shaoyaotang group and the Mesalazine group was not significant. ConclusionShaoyaotang can effectively treat DSS-induced mice with UC through the SIRT6/HIF-1α pathway， and its mechanism of action may be related to the regulation of the SIRT6/HIF-1α pathway and glucose metabolism reprogramming and the inhibition of glycolysis.

ObjectiveTo investigate the role of silent information regulatory protein （SIRT6）/hypoxia-inducible factor-1α （HIF-1α） pathway in regulating the reprogramming of glucose metabolism in ulcerative colitis （UC） and the mechanism of intervention of Shaoyaotang. MethodsForty-eight c57bL/6 mice were randomly divided into a blank group， a model group， a Mesalazine group （0.42 g·kg^-1）， a Shaoyaotang group （31.08 g·kg^-1）， an inhibitor group （OSS-128167， 50 mg·kg^-1）， and an inhibitor + Shaoyaotang group （50 mg·kg^-1 OSS-128167 + 31.08 g·kg^-1 Shaoyaotang）. A UC model was established by the administration of 2.5% dextran sulfate sodium （DSS） solution for mice in other groups for 7 d， except for the blank group. The mice in each group were treated with saline， Mesalazine， Shaoyaotang， inhibitor， and inhibitor + Shaoyaotang， respectively， for 7 d. The mice were necropsied 24 h after the last administration of the drug. The blood was collected from the orbital region， and colon tissue was taken. Hematoxylin-eosin （HE） staining was used to observe the pathological changes in colon tissue. Enzyme-linked immunosorbent assay （ELISA） was employed to detect serum interleukin （IL）-10， IL-17， and IL-6 levels. A biochemical method was used to detect glucose and lactate dehydrogenase A （LDHA） levels. Immunohistochemistry （IHC） was employed to detect IL-22 and transforming growth factor-β₁ （TGF-β₁） levels in colon tissue， and Western blot and real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） were used to detect relative protein and mRNA expressions of SIRT6， HIF-1α， and LDHA. ResultsCompared with those of the blank group， disease activity index （DAI） scores of mice in the model group and inhibitor group were significantly increased （P<0.01）. The length of colon tissue was significantly shortened， and colon tissue was congested and eroded. The pathohistological scores were significantly increased （P<0.01）. The levels of serum inflammatory factors IL-17 and IL-6 were significantly elevated， and the levels of IL-10 were significantly decreased （P<0.01）. The protein expressions of IL-22 and TGF-β₁ were significantly reduced in colon tissue （P<0.01）. The relative protein and mRNA expressions of SIRT6 were significantly decreased （P<0.01）， and the relative protein and mRNA expressions of HIF-1α and LDHA and the contents of glucose and lactate were significantly elevated （P<0.01）. The level of inflammation in the colon of the mice in the inhibitor group was more severe than that in the model group （P<0.01）. Compared with the model group， the Mesalazine group， the Shaoyaotang group， and the inhibitor + Shaoyaotang group showed reduced colonic injury， significant decrease in serum IL-17 and IL-6， significant increase in IL-10 （P<0.01）， significant increase in the protein expressions of IL-22 and TGF-β₁ in colon tissue （P<0.01）， significant increase in the protein expressions of SIRT6 and the relative mRNA expressions （P<0.01）， and significant reduction in the protein expressions of HIF-1α and LDHA， the relative mRNA expressions， and the contents of glucose and lactate （P<0.01）. Compared with those in the Shaoyaotang group， the serum IL-17 and IL-6 were significantly increased， and IL-10 was significantly decreased in the inhibitor + Shaoyaotang group （P<0.01）. The protein expressions of IL-22 and TGF-β₁ in colon tissue were significantly decreased （P<0.01）. The expressions of SIRT6 protein and the relative mRNA expressions were significantly decreased （P<0.01）. The protein expressions of HIF-1α and LDHA， the relative mRNA expressions， and the contents of glucose and lactate were significantly elevated （P<0.01）. However， the difference between the Shaoyaotang group and the Mesalazine group was not significant. ConclusionShaoyaotang can effectively treat DSS-induced mice with UC through the SIRT6/HIF-1α pathway， and its mechanism of action may be related to the regulation of the SIRT6/HIF-1α pathway and glucose metabolism reprogramming and the inhibition of glycolysis.

OBJECTIVE To compare the measures taken by China， the U.S. and Japan to adapt drug instructions to aging， and provide reference for the reform of elderly-friendly drug instructions in China. METHODS The relevant documents published by the official websites of National Medical Products Administration of China， the U.S. FDA， and Pharmaceuticals and Medical Devices Agency of Japan， were consulted. Additionally， relevant literature from comprehensive databases such as CNKI， Wanfang data， and Web of Science， as well as search engines， was reviewed to understand the measures taken by the above countries in elderly-friendly management process of drug instructions. The comparative analysis was conducted for elderly-friendly adaptations of drug instructions in China， the U.S. and Japan， and the suggestions were put forward for the reform of elderly-friendly drug instructions in China. RESULTS & CONCLUSIONS The measures taken by China， the U. S.， and Japan in the process of elderly- friendly management of drug labels had different emphases： China adopted large fonts and simplified drug instructions to alleviate the problem of the elderly being unable to read and understand drug instructions； the U.S. had set up a special section for the elderly in the drug instructions for special populations and issued the principles for writing information on medications for the elderly. The U. S. and Japan had established a classification management system for patient instructions and professional instructions， promoted structured electronic instructions， and built a unified electronic instructions platform. It is recommended that China incorporate elderly-specific medication information into the writing requirements of drug instructions， improve specific measures to encourage the reform of drug instructions suitable for the elderly， improve the accessibility and readability of electronic drug instructions， and build a drug instruction information disclosure platform to better ensure the safety of medication for the elderly.

Tumors are the second leading cause of death worldwide. Exosomes are a type of extracellular vesicle secreted from multivesicular bodies, with particle sizes ranging from 40 to 160 nm. They regulate the tumor microenvironment, proliferation, and progression by transporting proteins, nucleic acids, and other biomolecules. Compared with other drug delivery systems, exosomes derived from different cells possess unique cellular tropism, enabling them to selectively target specific tissues and organs. This homing ability allows them to cross biological barriers that are otherwise difficult for conventional drug delivery systems to penetrate. Due to their biocompatibility and unique biological properties, exosomes can serve as drug delivery systems capable of loading various anti-tumor drugs. They can traverse biological barriers, evade immune responses, and specifically target tumor tissues, making them ideal carriers for anti-tumor therapeutics. This article systematically summarizes the methods for exosome isolation, including ultracentrifugation, ultrafiltration, size-exclusion chromatography (SEC), immunoaffinity capture, and microfluidics. However, these methods have certain limitations. A combination of multiple isolation techniques can improve isolation efficiency. For instance, combining ultrafiltration with SEC can achieve both high purity and high yield while reducing processing time. Exosome drug loading methods can be classified into post-loading and pre-loading approaches. Pre-loading is further categorized into active and passive loading. Active loading methods, including electroporation, sonication, extrusion, and freeze-thaw cycles, involve physical or chemical disruption of the exosome membrane to facilitate drug encapsulation. Passive loading relies on drug concentration gradients or hydrophobic interactions between drugs and exosomes for encapsulation. Pre-loading strategies also include genetic engineering and co-incubation methods. Additionally, we review approaches to enhance the targeting, retention, and permeability of exosomes. Genetic engineering and chemical modifications can improve their tumor-targeting capabilities. Magnetic fields can also be employed to promote the accumulation of exosomes at tumor sites. Retention time can be prolonged by inhibiting monocyte-mediated clearance or by combining exosomes with hydrogels. Engineered exosomes can also reshape the tumor microenvironment to enhance permeability. This review further discusses the current applications of exosomes in delivering various anti-tumor drugs. Specifically, exosomes can encapsulate chemotherapeutic agents such as paclitaxel to reduce side effects and increase drug concentration within tumor tissues. For instance, exosomes loaded with doxorubicin can mitigate cardiotoxicity and minimize adverse effects on healthy tissues. Furthermore, exosomes can encapsulate proteins to enhance protein stability and bioavailability or carry immunogenic cell death inducers for tumor vaccines. In addition to these applications, exosomes can deliver nucleic acids such as siRNA and miRNA to regulate gene expression, inhibit tumor proliferation, and suppress invasion. Beyond their therapeutic applications, exosomes also serve as tumor biomarkers for early cancer diagnosis. The detection of exosomal miRNA can improve the sensitivity and specificity of diagnosing prostate and pancreatic cancers. Despite their promising potential as drug delivery systems, challenges remain in the standardization and large-scale production of exosomes. This article explores the future development of engineered exosomes for targeted tumor therapy. Plant-derived exosomes hold potential due to their superior biocompatibility, lower toxicity, and abundant availability. Furthermore, the integration of exosomes with artificial intelligence may offer novel applications in diagnostics, therapeutics, and personalized medicine.

ObjectiveTo study the effect of Zuoguiwan on the development of skin barrier in the neonatal rat model of congenital kidney deficiency and unveil the underlying mechanism. MethodsSixty rats were paired in a female-to-male ratio of 2∶1， and the pregnant rats were assigned into control， congenital kidney deficiency， and low- and high-dose （2 and 8 g·kg^-1， respectively） Zuoguiwan groups. The pregnant rats in other groups except the control group were exposed to chronic unpredictable mild stress for the modeling of congenital kidney deficiency. The rats in the control group and congenital kidney deficiency group were administrated with normal saline by gavage， and those in Zuoguiwan groups with Zuoguiwan suspension by gavage from day 1 of pregnancy. The serum level of interleukin-6 （IL-6） in the neonatal rats on the day of birth was determined by enzyme-linked immunosorbent assay. The full-thickness skin of neonatal rats on the day of birth was removed from the same position on the back and stained with hematoxylin-eosin for observation of histopathological changes， measurement of skin thickness， and counting of hair follicles. Terminal deoxynucleotidyl transferase-mediated nick end labeling was used to detect the apoptosis of skin tissue cells. The expression of interleukin-6 receptor （IL-6R） and interleukin-17A （IL-17A） in the skin tissue was assessed by immunohistochemistry and Western blot， and the expression of occludin， connexin 43 （Cx43）， and zonula occludens-1 （ZO-1） in the skin tissue was assessed by immunofluorescence and Western blot. ResultsCompared with those in the control group， the neonatal rats in the congenital kidney deficiency group showed a rise in the serum IL-6 level （P<0.01）， decreases in stratum corneum thickness， skin thickness， and number of hair follicles （P<0.01）， increases in the expression of IL-6R and IL-17A in the skin tissue （P<0.01） and the number of apoptotic cells （P<0.01）， and decreases in the expression of occludin， Cx43， ZO-1 （P<0.05）. Compared with the congenital kidney deficiency group， the low- and high-dose Zuoguiwan groups showed declines in serum IL-6 level （P<0.05）. The low-dose group showed increased number of hair follicles （P<0.05）， and the high-dose group presented thickened stratum corneum （P<0.01）， increased number of hair follicles （P<0.01）， and down-regulated expression of IL-6R and IL-17A in the skin tissue （P<0.05， P<0.01）. Both Zuoguiwan groups showcased decreased number of apoptotic cells （P<0.05， P<0.01）， and the high-dose group showed up-regulated expression of occludin， Cx43， and ZO-1 in the skin tissue （P<0.05， P<0.01）. ConclusionZuoguiwan can reduce the levels of IL-6 in the serum and IL-6R and IL-17A in the skin tissue and improve the expression of intercellular junction proteins， thereby ameliorating the abnormal development of the skin barrier in the neonatal rat model of congenital kidney deficiency.

ObjectiveTo study the effect of Zuoguiwan on the development of skin barrier in the neonatal rat model of congenital kidney deficiency and unveil the underlying mechanism. MethodsSixty rats were paired in a female-to-male ratio of 2∶1， and the pregnant rats were assigned into control， congenital kidney deficiency， and low- and high-dose （2 and 8 g·kg^-1， respectively） Zuoguiwan groups. The pregnant rats in other groups except the control group were exposed to chronic unpredictable mild stress for the modeling of congenital kidney deficiency. The rats in the control group and congenital kidney deficiency group were administrated with normal saline by gavage， and those in Zuoguiwan groups with Zuoguiwan suspension by gavage from day 1 of pregnancy. The serum level of interleukin-6 （IL-6） in the neonatal rats on the day of birth was determined by enzyme-linked immunosorbent assay. The full-thickness skin of neonatal rats on the day of birth was removed from the same position on the back and stained with hematoxylin-eosin for observation of histopathological changes， measurement of skin thickness， and counting of hair follicles. Terminal deoxynucleotidyl transferase-mediated nick end labeling was used to detect the apoptosis of skin tissue cells. The expression of interleukin-6 receptor （IL-6R） and interleukin-17A （IL-17A） in the skin tissue was assessed by immunohistochemistry and Western blot， and the expression of occludin， connexin 43 （Cx43）， and zonula occludens-1 （ZO-1） in the skin tissue was assessed by immunofluorescence and Western blot. ResultsCompared with those in the control group， the neonatal rats in the congenital kidney deficiency group showed a rise in the serum IL-6 level （P<0.01）， decreases in stratum corneum thickness， skin thickness， and number of hair follicles （P<0.01）， increases in the expression of IL-6R and IL-17A in the skin tissue （P<0.01） and the number of apoptotic cells （P<0.01）， and decreases in the expression of occludin， Cx43， ZO-1 （P<0.05）. Compared with the congenital kidney deficiency group， the low- and high-dose Zuoguiwan groups showed declines in serum IL-6 level （P<0.05）. The low-dose group showed increased number of hair follicles （P<0.05）， and the high-dose group presented thickened stratum corneum （P<0.01）， increased number of hair follicles （P<0.01）， and down-regulated expression of IL-6R and IL-17A in the skin tissue （P<0.05， P<0.01）. Both Zuoguiwan groups showcased decreased number of apoptotic cells （P<0.05， P<0.01）， and the high-dose group showed up-regulated expression of occludin， Cx43， and ZO-1 in the skin tissue （P<0.05， P<0.01）. ConclusionZuoguiwan can reduce the levels of IL-6 in the serum and IL-6R and IL-17A in the skin tissue and improve the expression of intercellular junction proteins， thereby ameliorating the abnormal development of the skin barrier in the neonatal rat model of congenital kidney deficiency.

Background: Despite the fact that an increasing number of studies have focused on developing therapies for acute lung injury, managing acute respiratory distress syndrome (ARDS) remains a challenge in intensive care medicine.Whether the pathology of animal models with acute lung injury in prior studies differed from clinical symptoms of ARDS, resulting in questionable management for human ARDS. To evaluate precisely the therapeutic effect of trans‑ planted stem cells or medications on acute lung injury, we developed an animal model of severe ARDS with lower lung function, capable of keeping the experimental animals survive with consistent reproducibility. Establishing this animal model could help develop the treatment of ARDS with higher efficiency. Results: In this approach, we intratracheally delivered bleomycin (BLM, 5 mg/rat) into rats’ left trachea via a needle connected with polyethylene tube, and simultaneously rotated the rats to the left side by 60 degrees. Within sevendays after the injury, we found that arterial blood oxygen saturation ­(SpO2 ) significantly decreased to 83.7%, partial pressure of arterial oxygen ­(PaO2 ) markedly reduced to 65.3 mmHg, partial pressure of arterial carbon dioxide ­(PaCO2 )amplified to 49.2 mmHg, and the respiratory rate increased over time. Morphologically, the surface of the left lung appeared uneven on Day 1, the alveoli of the left lung disappeared on Day 2, and the left lung shrank on Day 7. A his‑ tological examination revealed that considerable cell infiltration began on Day 1 and lasted until Day 7, with a larger area of cell infiltration. Serum levels of IL-5, IL-6, IFN-γ, MCP-1, MIP-2, G-CSF, and TNF-α substantially rose on Day 7. Conclusions This modified approach for BLM-induced lung injury provided a severe, stable, and one-sided (left-lobe) ARDS animal model with consistent reproducibility. The physiological symptoms observed in this severe ARDS animal model are entirely consistent with the characteristics of clinical ARDS. The establishment of this ARDS animal model could help develop treatment for ARDS.