BACKGROUND:The extracellular-regulated protein kinase 5(ERK5)signaling protein is essential for the survival of organisms,and resveratrol can promote osteoblast proliferation through various pathways.However,whether resveratrol can regulate osteoblast function through the ERK5 signaling protein needs further verification. OBJECTIVE:To explore the regulatory effect of ERK5 on the proliferation of MC3T3-E1 cells and related secreted proteins,and to further verify whether resveratrol can complete the above process by activating ERK5. METHODS:Mouse MC3T3-E1 preosteoblasts were treated with complete culture medium,XMD8-92(an ERK5 inhibitor),epidermal growth factor(an ERK5 activator),resveratrol alone,XMD8-92+EGF,and resveratrol+XMD8-92,respectively.Western blot assay was used to detect the expression of ERK5 and p-ERK5 proteins,proliferation-related proteins Cyclin D1,CDK4 and PCNA,and osteoblast-secreted proteins osteoprotegerin and receptor activator of nuclear factor-κB ligand in MC3T3-E1 cells of each group.The fluorescence intensity of ERK5,osteoprotegerin and receptor activator of nuclear factor-κB ligand in each group was detected by cell immunofluorescence staining,and cell proliferation was detected by EdU staining,respectively.The appropriate concentration and time of resveratrol intervention in MC3T3-E1 cells were determined by cell morphology observation and cell counting kit-8 assay. RESULTS AND CONCLUSION:The activation of ERK5 signaling protein could effectively promote the proliferation of MC3T3-E1 cells,up-regulate the osteoprotegerin/receptor activator of nuclear factor-κB ligand ratio.The appropriate concentration and time for resveratrol intervention in MC3T3-E1 cells was 5 μmol/L and 24 hours,respectively.Resveratrol could activate ERK5 signaling protein,thereby promoting osteoblast proliferation and up-regulating the osteoprotegerin/RANKL ratio.All these results indicate that resveratrol can promote the proliferation of MC3T3-E1 cells and up-regulate the osteoprotegerin/RANKL ratio by activating the ERK5 signaling protein.

BACKGROUND:Prostaglandin E1(PGE1)has been shown to play a regulatory role in vasodilatation,inflammation,and leukocyte migration and adhesion,but its effects on spinal cord microcirculation after traumatic spinal cord injury(SCI)remain poorly understood. OBJECTIVE:To investigate the mechanism underlying the protective effects of PGE1 administered during the acute phase of traumatic SCI in rats on the regulation of vascular-related factors and microcirculatory function. METHODS:Seventy-two female Sprague-Dawley rats were divided into three groups(n=24 per group):control group,SCI group,and PGE1 group.An in vivo SCI model was established using Allen's blow method.Rats in the PGE1 group were injected with PGE1(10 μg/kg)via the tail vein immediately after SCI.Spinal cord microcirculatory blood flow and oxygen saturation,spinal cord microvessel diameter and area,spinal cord water content,vascular function regulators(von Willebrand factor,thromboxane A2,prostacyclin,endothelin-1),and inflammatory factors(tumor necrosis factor-α,interleukin-1β)were measured at 2 and 24 hours after SCI. RESULTS AND CONCLUSION:At 2 hours after SCI,the diameter and area of spinal cord microvessels,spinal cord microcirculatory blood flow,and oxygen saturation in the PGE1 group were higher than those in the SCI group(P<0.05),the water content of the spinal cord was lower than that in the SCI group(P<0.05),and the level of plasma von Willebrand Factor,the ratio of thromboxane A2/prostacyclin of the spinal cord and the level of endothelin-1 were lower than those in the SCI group(P<0.05).At 24 hours after SCI,the spinal cord microvessel area,blood flow,and oxygen saturation of rats in the PGE1 group were higher than those in the SCI group(P<0.05),the spinal cord water content was lower than that in the SCI group(P<0.05),and the levels of plasma von Willebrand factor,spinal cord tissue thromboxane A2/prostacyclin ratio and the levels of endothelin-1,tumor necrosis factor-α and interleukin-1β were lower than those in the SCI group(P<0.05).The diameter and area of spinal cord microvessels,spinal cord microcirculatory blood flow and blood oxygen saturation of rats in the SCI group were higher than those in the SCI group at 24 hours post-injury(P<0.05),and the levels of plasma von Willebrand factor,spinal tissue thromboxane A2/prostacyclin ratio,tumor necrosis factor-α and interleukin-1β were higher than those at 2 hours post-injury(P<0.05),but the level of endothelin-1 in spinal cord tissue was lower than that at 2 hours(P<0.05).The blood flow and oxygen saturation of spinal cord microcirculation in the PGE1 group rats at 24 hours post-injury were lower than those at 2 hours post-injury(P<0.05),and the diameter and area of spinal cord microvessels and water content of the spinal cord were higher than those at 2 hours post-injury(P<0.05).The above results indicate that intravenous administration of PGE1 in SCI rats immediately after injury can regulate vascular function regulators,inflammatory factors and improve microcirculation of the spinal cord after SCI,which provides a potential basis for the search of drugs for the treatment of acute SCI.

BACKGROUND:Immunosuppression leads to impaired body immune function and aggravates the disease.Herb-partitioned moxibustion can effectively regulate immune function and improve immunity in the body,but its regulatory mechanism has not been elucidated. OBJECTIVE:To sequence immunosuppressed model rats treated with herb-partitioned moxibustion using bioinformatics techniques based on transcriptomics and to explore the mechanisms by which it regulates immunity. METHODS:Twenty-four Sprague-Dawley rats were randomly assigned to three groups:control,model,and herb-partitioned moxibustion groups,with eight rats in each group.The model and herb-partitioned moxibustion groups were subjected to establishment of an immune suppression model by intraperitoneal injection of cyclophosphamide at a dose of 35 mg/kg for 3 consecutive days.No interventions were administered to the control and model groups after modeling.In contrast,the herb-partitioned moxibustion group received moxibustion treatment at Zhongwan,Shenque,Guanyuan,and Zusanli acupoints using a combination of moxa and herbal cakes,once a day,for 10 consecutive days,with samples being collected the day after the end of the intervention.Peripheral blood was collected from all groups of rats to measure their white blood cell count.RNA-seq was performed on the Illumina sequencing platform,and differentially expressed genes were selected for bioinformatics analysis using the GO and KEGG databases. RESULTS AND CONCLUSION:Compared with the control group,the model group exhibited a significant decrease in white blood cell count(P<0.001).RNA-seq analysis identified 3 026 differentially expressed genes between the model and control groups,with 1 565 upregulated and 1 461 downregulated.There were 535 differentially expressed genes identified between the herb-partitioned moxibustion group and the model group,with 280 upregulated and 255 downregulated.The Venn diagram analysis revealed that 159 genes were downregulated in the model group compared with the control group.However,after moxibustion with herbal cakes,these genes were upregulated.Protein-protein interaction network analysis identified 10 core targets,including Oasl,Oas2,Isg15,Herc6,Mx2,Helz2,Mx1,Syk,Hspa1a,and Ret.According to GO and KEGG analyses,moxibustion with herbal cakes regulated the body through pathways related to immune response,viruses,angiogenesis,and the autoimmune system.To conclude,there is a significant association between herbal cake-separated moxibustion intervention and immune suppression targets,including Oasl,Oas2,Isg15,Herc6,Mx2,Helz2,and Mx1.The intervention exhibits regulatory effects in the pathways related to immune responses,viral activities,and angiogenesis.

BACKGROUND:Studies have shown that metformin has anti-inflammatory,anti-tumor,anti-aging and vasoprotective effects,and can inhibit the progression of osteoarthritis,but its specific mechanism of action remains unclear. OBJECTIVE:To investigate the mechanism of metformin on cartilage protection in a rat model of osteoarthritis. METHODS:Forty male Sprague-Dawley rats were randomly divided into four groups(n=10 per group):blank,control,sham-operated,and metformin groups.The blank group did not undergo any surgery.In the sham-operated group,the joint cavity was exposed.In the model group and the metformin group,the modified Hulth method was used to establish the osteoarthritis model.At 1 day after modeling,the rats in the metformin group were given 200 mg/kg/d metformin by gavage,and the model,blank,and sham-operated groups were given normal saline by gavage.Administration in each group was given for 4 weeks consecutively.Hematoxylin-eosin staining,toluidine blue staining,and safranin O-fast green staining were used to observe the morphological structure of rat knee joints.Immunohistochemical staining and western blot were used to detect the protein expression of SOX9,type Ⅱ collagen,a disintegrin and metalloproteinase with thrombospondin motifs 5(ADAMTS5),Beclin1,P62,phosphatidylinositol 3-kinase(PI3K),p-PI3K,protein kinase B(AKT),p-AKT,mammalian target of rapamycin(Mtor),and p-Mtor in rat cartilage tissue. RESULTS AND CONCLUSION:The results of hematoxylin-eosin,toluidine blue and safranin O-fast green staining showed smooth cartilage surface of the knee joints and normal histomorphology in the blank group and the sham-operated group,while in the model group,there was irregular cartilage surface of the knee joint and cartilage damage,with a decrease in the number of chondrocytes and the content of proteoglycans in the cartilage matrix.In the metformin group,there was a significant improvement in the damage to the structure of the cartilage in the knee joints of the rats,and the cartilage surface tended to be smooth,with an increase in the number of chondrocytes and the content of proteoglycans in the cartilage matrix.Immunohistochemistry staining and western blot results showed that compared with the control and sham-operated groups,the expression of SOX9,type Ⅱ collagen,and Beclin1 proteins in the cartilage tissue of rats in the model group was significantly decreased(P<0.05).Conversely,the expression of ADAMTS5,P62,as well as p-PI3K,p-AKT,and p-Mtor proteins was significantly increased(P<0.05).Furthermore,compared with the model group,the expression of SOX9,type Ⅱ collagen,and Beclin1 proteins in the cartilage tissue of rats in the metformin group was significantly increased(P<0.05),while the expression of ADAMTS5,P62,as well as p-PI3K,p-AKT,and p-Mtor proteins was significantly decreased(P<0.05).To conclude,Metformin can improve the autophagy activity of chondrocytes and reduce the degradation of cartilage matrix in osteoarthritis rats by inhibiting the activation of PI3K/AKT/Mtor signaling pathway,thus exerting a protective effect on articular cartilage.

BACKGROUND:Studies have demonstrated that postmenopausal osteoporosis is related to female reproductive characteristics and exercise diets,but few studies have demonstrated whether female reproductive characteristics and exercise diets have an effect on vitamin D in postmenopausal women. OBJECTIVE:To investigate the relationship of vitamin D levels with female reproductive characteristics and exercise diets and their influencing factors in postmenopausal women in Beijing. METHODS:Totally 727 postmenopausal women with an age range of 46-75 years old who received on-site questionnaires in 17 communities of Beijing from September 2017 to May 2018 were selected as the study subjects,and the questionnaires included the subjects'basic information and history of menstruation,menopause,pregnancy,and exercise diet.An electrochemiluminescence immunoassay analyzer and its auxiliary reagents were used to determine 25-(OH)D levels.Bone mineral density and T values of the lumbar spine(L1-L4,whole)and both hips(femoral neck,whole)were determined using a dual-energy X-ray bone mineral density detector.The correlation of vitamin D with reproductive characteristics and exercise diet was observed,as well as the influencing factors of vitamin D were analyzed. RESULTS AND CONCLUSION:There were 136 cases(18.7%)in the vitamin D normal group,389 cases(53.5%)in the vitamin D insufficient group,and 202 cases(27.8%)in the vitamin D deficient group.The mean vitamin D level was(15.60±5.85)ng/mL.With the increase of vitamin D level,the bone mineral density value and T value of different parts of the body also increased.Vitamin D level was positively correlated with age at menarche,days of menstrual duration,stage of menopause,activity,diet type,and dietary preference(P<0.05);was negatively correlated with menstrual cycle,age at menopause,and number of childbearing(P<0.05);and had no correlation with age at first conception and number of pregnancies(P>0.05).The results of multifactorial ordered Logistic regression analyses showed that there was a positive correlation between the frequency of drinking dairy products and vitamin D level(P<0.05),and dairy products were a protective factor for vitamin D level.To conclude,vitamin D levels are generally insufficient and bone mineral density values are generally low in postmenopausal women in Beijing.Vitamin D levels are correlated with some reproductive characteristics and exercise diets,and drinking dairy products is a protective factor.Therefore,it is possible to intervene in the dietary situation of postmenopausal women by means of health education about osteoporosis and by increasing vitamin D levels in order to increase bone density values and reduce the prevalence of osteoporosis in the postmenopausal period.

BACKGROUND:Rheumatoid arthritis is an inflammatory disease.Many studies have shown that wogonin has a good anti-inflammatory effect on rheumatoid arthritis,but its exact efficacy and specific mechanism of action remain to be clarified. OBJECTIVE:To investigate the mechanism of wogonin ameliorating joint inflammation by regulating endoplasmic reticulum stress pathway in rats with collagen-induced arthritis. METHODS:(1)At the animal level:Female Wistar rats were divided into healthy control group,arthritis model group and wogonin treatment group.Rat models of arthritis in the latter two groups were established by subcutaneous injection of bovine type Ⅱ collagen and adjuvant.In the wogonin group,wogonin was given by gavage for 28 consecutive days after modeling.During this period,the rats in each group were weighed,and arthritis score and ankle swelling were measured every 7 days.After the experiment,the pathological changes of the joint were observed,the mRNA and protein levels of endoplasmic reticulum stress pathway GRP78 and CHOP were detected by qRT-PCR,western blot,and immunohistochemistry.(2)At the cellular level,cell counting kit-8 was used to detect the cytotoxic effect of wogonin on fibroblast-like synoviocytes from rats with collagen-induced arthritis.The fibroblast-like synoviocytes induced by thapsigargin were treated with different concentrations of wogonin.The levels of interleukin-1β and tumor necrosis factor-α in the cell supernatant were detected by ELISA,and the intracellular reactive oxygen species in each group were determined by DCFH-DA probe method.The mRNA and protein levels of GRP78,IRE1α,XBP1s and CHOP were detected by qRT-PCR and western blot,respectively. RESULTS AND CONCLUSION:Compared with the healthy control group,arthritis index score and ankle swelling degree in the arthritis model group were increased(P<0.01),synovial hyperplasia,inflammatory cell infiltration,cartilage destruction and bone erosion were observed in pathological sections,and the mRNA and protein expressions of GRP78 and CHOP in the ankle were significantly increased(P<0.01),which were mainly located in synovial tissue and articular surface.Compared with the arthritis model group,the arthritis index score and ankle swelling degree in the wogonin treatment group were decreased(P<0.05),synovial hyperplasia and the number of inflammatory cells were decreased,cartilage destruction and bone erosion were alleviated,the mRNA and protein expression levels of GRP78 and CHOP in the ankle were decreased(P<0.05),particularly in synovial tissue and on the articular surface.There was no significant difference in body mass among the three groups(P>0.05).In the cell experiment,200 μmol/L wogonin significantly reduced the survival rate of fibroblast-like synoviocytes(P<0.01).Compared with the blank control group,the levels of interleukin-1β,tumor necrosis factor-α,content of reactive oxygen species,and mRNA and protein expression of GRP78,IRE1α,XBP1s,and CHOP in the thapsigargin group were significantly increased(P<0.05);compared with the thapsigargin group,50 and 100 μmol/L wogonin significantly reduced the levels of interleukin-1β and tumor necrosis factor-α in the cell supernatant(P<0.05,P<0.01),and 100 μmol/L wogonin significantly reduced the content of reactive oxygen species(P<0.01)and down-regulated the mRNA and protein expression levels of GRP78,IRE1α,XBP1s and CHOP(all P<0.05).These results suggest that wogonin can effectively alleviate joint inflammatory responses in rats with collagen-induced arthritis,and the endoplasmic reticulum stress pathway may be the key target of its intervention.

BACKGROUND:Streptococcus mutans is an important pathogen of dental caries,and timely detection of its levels is of great significance for early detection and treatment of dental caries. OBJECTIVE:To evaluate the effect of loop-mediated isothermal amplification(FTA-LAMP)direct extraction of Streptococcus mutans DNA. METHODS:(1)Bacterial suspensions containing ATCC standard strains(Streptococcus mutans)were prepared and inoculated into the brain-heart leachate medium.After mixed thoroughly,the mixture was then diluted in a 10-fold gradient into seven concentrations(4.2×107,4.2×106,4.2×105,4.2×104,4.2×103,4.2×102,4.2×10 CFU/mL),two parallel controls were made for each dilution level,and sterile water was used as a blank control.(2)The DNA of Streptococcus mutans was extracted using FTA Elute card,boiling method,kit extraction and lysate extraction methods separately and then amplified using LAMP technology was amplified.A specificity test was also performed to compare the differences between the four DNA extraction methods.RESULTS AND CONCLUSION:The DNA extracted by all four methods met the requirements for LAMP amplification.Specificity test results showed that only Streptococcus mutans could specifically amplify the target gene.The detection limit value of the DNA concentration was 4.2×103 CFU/mL for the lysate method,4.2×104 CFU/mL for the FTA Elute card extraction method,4.2×106 CFU/mL for the kit extraction method,and 4.2×107 CFU/mL for the boiling method.In the other aspects of the four extraction methods,the kit extraction method had the highest experimental cost,number of steps and time;the other three methods had the same number of steps,with the FTA Elute card method requiring the least amount of instruments,the boiling method having the lowest single cost,and the lysate extraction method taking the least amount of time.Only a small amount of bacteria were needed for successful extraction using both the FTA Elute card and lysate extraction methods.Compared with the FTA Elute card method,the lysate extraction method was superior in terms of time,but it had a high single cost and required more equipment.To conclude,the FTA-LAMP technology established in this study has the advantages of ease of operation,high specificity,high sensitivity,and visualization,which is expected to be a new way for efficient extraction and detection of Streptococcus mutans.

BACKGROUND:Troxerutin has been found to have a significant ameliorative effect on brain disorders,but there are fewer studies on the effects of troxerutin on the treatment of cerebral infarction and on neuronal cells. OBJECTIVE:To investigate the mechanism by which troxerutin regulates nuclear factor-κB signaling pathway to reduce brain injury and neuronal apoptosis in cerebral infarction rats. METHODS:Fifty clean grade rats were randomized into healthy group,model group,and troxerutin+nuclear factor-κB agonist group,troxerutin group,and nuclear factor-κB inhibitor group.Except for the healthy group,all other groups were used to establish a rat model of cerebral infarction by arterial ligation.The healthy and model groups were treated once a day with an equal amount of physiological saline by gavage.The troxerutin+nuclear factor-κB agonist group was intervened with 72 mg/kg troxerutin by gavage+20 mg/kg RANK intraperitoneally.The troxerutin group was treated with 72 mg/kg troxerutin by gavage.The nuclear factor κB inhibitor group was intervened intraperitoneally with 120 mg/kg nuclear factor κB inhibitor pyrrolidine disulfiram.Administration in each group was given once a day for 30 continuous days.Zea-longa was used to detect neurological damage in rats,hematoxylin-eosin staining was used to observe pathological changes,TUNEL was used to detect neuronal apoptosis,and immunoblotting and PCR were used to detect the expression of nuclear factor-κB p65 and nuclear factor-κB p50 at protein and mRNA levels,respectively. RESULTS AND CONCLUSION:Compared with the healthy group,the neurological function score,neuronal apoptosis rate,nuclear factor-κB p65,nuclear factor-κB p50 mRNA and protein expression levels were elevated in the model group(P＜0.05).Compared with the model group,the neurological function score,neuronal apoptosis rate,nuclear factor-κB p65 and nuclear factor-κB p50 mRNA and protein expression levels were decreased in the troxerutin+nuclear factor-κB agonist group(P＜0.05).Compared with the troxerutin+nuclear factor-κB agonist group,the neurological function score,neuronal apoptosis rate,nuclear factor-κB p65 and nuclear factor-κB p50 mRNA and protein expression levels were reduced in the troxerutin group and nuclear factor-κB inhibitor group(P＜0.05).In addition,there was no difference between the troxerutin group and the nuclear factor-κB inhibitor group(P＞0.05).In the model group,there was a large number of cytoplasmic vacuolation,obvious edema and necrosis,and a large number of inflammatory cell infiltrations.In the troxerutin+nuclear factor-κB agonist,the swelling of brain tissue was reduced,and reticulate structures and condensed cells were reduced,still with some edema.In the troxerutin group and nuclear factor-κB inhibitor group,brain tissue swelling,neuronal edema degeneration,cytoplasmic vacuolation and neuronal nucleus consolidation were reduced,and the inflammatory cell infiltration was significantly decreased.To conclude,troxrutin can reduce the expression of neurological impairment,inhibit neuronal apoptosis and improve the pathological injury of brain tissue in rats with cerebral infarction,and its mechanism of action may be related to the modulation of nuclear factor-κB expression and related signaling pathways.

BACKGROUND:Eucommia ulmoides has a certain osteogenic effect,which can promote the proliferation and differentiation of osteoblasts.However,it is unclear whether Eucommia ulmoides has effects on alveolar bone formation and Wnt/β-Catenin signaling pathway. OBJECTIVE:To investigate the mechanism by which Eucommia ulmoides promotes alveolar bone formation in ovariectomized rats based on the Wnt/β-Catenin signaling pathway. METHODS:Sixty female Sprague-Dawley rats were selected and randomly divided into five groups:blank control group,sham-operation group,model group,low-dose group Eucommia ulmoides group,and high-dose Eucommia ulmoides group,with twelve rats in each group.Osteoporosis animal models were constructed by bilateral oophorectomy in the model group and the low-dose and high-dose Eucommia ulmoides groups.The sham-operation group underwent the same method to remove adipose tissue of equal mass around the bilateral ovaries.Three months after surgery,the low-and high-dose Eucommia ulmoides groups were given 2.1 g/kg/d and 4.2 g/kg/d Eucommia ulmoides by gavage,respectively.The sham-operation group and model group were given the same amount of physiological saline by gavage.After 12 weeks of drug intervention,the changes in alveolar bone mass of rats in each group were observed through Micro-CT;hematoxylin-eosin staining was used to observe the pathological structural changes of alveolar bone in rats;enzyme linked immunosorbent assay was used to detect the expression levels of alkaline phosphatase and osteocalcin in the serum of rats;western blot was used to detect the expression levels of β-Catenin and Frizzled9 receptor proteins in the alveolar bone of rats;and real-time fluorescence quantitative PCR was used to detect the expression of osteocalcin,Runt-related transcription factor 2(Runx2),alkaline phosphatase,β-catenin,and frizzled9 mRNAs in alveolar bone tissues of rats. RESULTS AND CONCLUSION:Compared with the blank control group,bone volume fraction,trabecular number,trabecular thickness,and bone mineral density were reduced in the model group(P＜0.05),and trabecular separation was elevated(P＜0.05).Pathological observation showed that the arrangement of trabeculae was disordered and irregular,the trabeculae were thinned or broken,and the marrow cavity was enlarged in the model group,with a significant reduction in bone volume;the level of alkaline phosphatase in the serum was increased(P＜0.05),and the level of osteocalcin was decreased(P＜0.05);mRNA expression of alkaline phosphatase,osteocalcin,Runx2,β-catenin,and frizzled9 were decreased(P＜0.05);protein expression of β-Catenin and Frizzled9 was decreased(P＜0.05).Compared with the model group,the low-and high-dose Eucommia ulmoides groups showed an increase in bone volume fraction,trabecular number,trabecular thickness,and bone mineral density(P＜0.05)and a decrease in trabecular separation(P＜0.05).In the low-and high-dose Eucommia ulmoides groups,bone trabeculae were slightly aligned and thickened,with a significant increase in bone mass.Compared with the model group,the serum level of alkaline phosphatase was reduced(P＜0.05)and the serum level of osteocalcin was elevated(P＜0.05)in the low-and high-dose Eucommia ulmoides groups.Compared with the model group,the mRNA expression of alkaline phosphatase,osteocalcin,Runx2,β-catenin,and frizzled9 were increased in the low-and high-dose Eucommia ulmoides groups(P＜0.05).Compared with the model group,the protein expression of Frizzled9 was increased in the low-dose Eucommia ulmoides group(P＜0.05),while the protein expression of β-Catenin and Frizzled9 was increased in the high-dose Eucommia ulmoides group(P＜0.05).Compared with the low-dose Eucommia ulmoides group,the high-dose Eucommia ulmoides group had a more significant improvement in the above indexes.To conclude,Eucommia ulmoides can effectively promote the alveolar bone formation,and its mechanism of action might be related to the activation of the Wnt/β-catenin signaling pathway.

BACKGROUND:It has been proved clinically that adhesion of fibrous scar with the dura mater or nerve root after lumbar operation is an important factor for postoperative symptoms,such as postoperative pain and numbness. OBJECTIVE:To verify the inhibitory effect of autologous ligamentum flavum on the formation of epidural fibrous scar after lumbar surgery and explore the possible molecular biological mechanism. METHODS:Forty-eight Japanese white rabbits(6-8 months old)were randomly divided into three groups:a ligamentum flavum preservation group,a ligamentum flavum non-preservation group,and an autologous fat reposition group.A lumbar laminectomy model was established in all the three groups of rabbits,and rabbit epidural tissues were collected at 3 and 6 weeks after modeling.Hematoxylin-eosin staining was used to observe histological changes and the number and density of fibroblasts,VG staining was used to observe the percentage of collagen fiber area,and immunohistochemistry was used to observe the expression of transforming growth factor β1 and Smad3 proteins. RESULTS AND CONCLUSION:Hematoxylin-eosin staining results revealed that fibroblasts in the ligamentum flavum preservation group were few and loosely arranged,while the cells in the ligamentum flavum non-preservation and autologous fat reposition groups were more numerous and closely arranged.The number density of fibroblasts in the ligamentum flavum preservation group was lower than that in the ligamentum flavum non-preservation and autologous fat reposition groups at 3 and 6 weeks after surgery(P＜0.05);however,there was no significant difference between the latter two groups.VG staining results showed that the collagen fibers in the ligamentum flavum preservation group were sparse and distributed unevenly,while a lot of red collagen fibers were gathered in the ligamentum flavum non-preservation and autologous fat reposition groups.The area percentage of collagen fibers in the ligamentum flavum preservation group was lower than that in the ligamentum flavum non-preservation and autologous fat reposition groups at 3 and 6 weeks after surgery(P＜0.05),but there was no significant difference between the latter two groups.The results of immunohistochemistry showed that the degree of positive staining of retained histone the ligamentum flavum preservation group was significantly lower than that of the other two groups.The absorbance value of transforming growth factor β1 and Smad3 in the ligamentum flavum preservation group was significantly lower than that in the other two groups at 3 and 6 weeks after surgery(P＜0.05),but there was no significant difference between the latter two groups.To conclude,there are different degrees of epidural fibrous scar formation after lumbar surgery.If the ligamentum flavum is preserved,it can help to reduce the number of epidural fibroblasts as well as the formation of collagen fibers,thus reducing the adhesion of the fibrous scar tissue to the dural sac and nerve root.The mechanism is not only a purely mechanical blockade,but also to reduce the formation of epidural fibrous scar by interfering with the transforming growth factor β1/Smad3 signaling pathway.