Objective To examine the toxicity and sublethal effects of calcium cyanamide against susceptible isolates of Aedes albopictus, so as to provide insights into rational use of calcium cyanamide for integrated management of Ae. albopictus. Methods The sublethal concentrations [30% lethal concentration (LC₃₀) and median lethal concentration (LC₅₀)] of calcium cyana mide against susceptible strains of Ae. albopictus were determined using the larval immersion test. With 100 mL of dechlorinated water as the control group, after the larvae of susceptible strains of Ae. albopictus were immersed in calcium cyanamide for 24 hours, the pupation rate, pupation duration, emergence rate, number of eggs laid, percentage of eggs hatched, and lifespan of Ae. albopictus were calculated and compared post-treatment with calcium cyanamide at different sublethal concentrations. The midgut tissues of larvae of susceptible strains of Ae. albopictus treated with 100 mg/L calcium cyanamide were sampled for pathological sectioning to observe midgut tissue damages. To evaluate the residual activity, 100 larvae of susceptible strains of Ae. albopictus were treated with 200 mg/L and 500 mg/L calcium cyanamide, and the mortality of larvae was calculated every 24 hour, with dead larvae replaced until no larval death. Results The regression equation for the toxicity of calcium cyanamide against larvae of susceptible strains of Ae. albopictus was y = -9.441 + 4.657x, with an LC₅₀ of 106.42 mg/L [95% confidence interval (CI): (94.64, 118.36) mg/L] and an LC₃₀ of 82.17 mg/L [95% CI: (94.64, 118.36) mg/L], respectively. After larvae of susceptible strains of Ae. albopictus were treated with sublethal concentrations (LC₃₀ and LC₅₀) of calcium cyanamide for 24 hours, there were reduced pupation and emergence rates of larvae (all P values < 0.000 1), prolonged pupal stage (both P values < 0.000 1), reduced numbers of eggs laid by survival female Ae. albopictus (both P values < 0.000 1), reduced percentages of eggs hatched by Ae. albopictus eggs (both P values < 0.000 1), and reduced median survival period of survival female Ae. albopictus (χ² = 9.36 and 20.33, both P values < 0.01) in the LC₃₀ and LC₅₀ groups relative to the control group. There was a numerical decline in the median survival period of survival female Ae. albopictus in the LC₃₀ groups relative to the control group (χ² = 2.42, P > 0.05), and there was a significant decline in the median survival period of survival female Ae. albopictus in the LC₅₀ group relative to the control group (χ² = 11.42, P < 0.01). Histopathological examinations showed severe damages to the midgut tissues of larvae of susceptible strains of Ae. albopictus, and residual activity assay revealed that the mortality of larvae of susceptible strains of Ae. albopictus was both 0 on day 32 post-treatment with calcium cyanamide at a concentration of 200 mg/L and on day 70 post-treatment with calcium cyanamide at a concentration of 500 mg/L, showing complete loss of the larvicidal activity of calcium cyanamide. Conclusions Calcium cyanamide is highly toxic against susceptible strains of Ae. albopictus, and calcium cyanamide at sublethal concentrations (LC₃₀ and LC₅₀) may inhibit growth, development, and reproductive capability of susceptible strains of Ae. albopictus, and shorten the lifespan of adult mosquitoes.

BACKGROUND: Doxorubicin hydrochloride (DOX) is extensively used in the treatment of various tumors. However, its clinical application is limited due to dose-dependent cardiotoxicity. Currently, few effective strategies exist to mitigate or eliminate DOX-induced cardiomyopathy (DIC). Although ferroptosis is implicated in DIC and its inhibition partially alleviates the condition, the direct targets of DOX in the progression of cardiotoxicity remain unclear. This study aimed to discover the direct targets of DOX in ferroptosis-mediated DIC. METHODS: A DOX pulldown assay was performed to identify proteins specifically binding to DOX in murine hearts, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify candidate proteins. A cardiac injury mouse model was established by DOX treatment. Based on this, multiple ferroptosis biomarkers were detected by flow cytometry, quantitative real-time polymerase chain reaction, western blotting, immunochemistry, etc. Besides, specific activator and inhibitor of signaling pathways were applied to illuminate molecular mechanisms. RESULTS: Glutathione S-transferase P1 (GSTP1) was identified as a DOX target. GSTP1 activity was inhibited in DOX-treated cardiomyocytes, while its overexpression significantly alleviated DIC. Moreover, GSTP1 overexpression inhibited acyl-CoA synthetase long-chain family member 4 (ACSL4)-dependent ferroptosis. Mechanistically, GSTP1 overexpression suppressed c-Jun N-terminal kinase (JNK) phosphorylation, thereby reducing reactive oxygen species (ROS) production and inhibiting ferroptosis in DIC. CONCLUSIONS This study identifies the DOX/GSTP1/JNK axis as a critical pathway mediating ACSL4-dependent ferroptosis in DIC. GSTP1 is highlighted as a potential key mediator of ferroptosis and a promising therapeutic target for DIC.

Objective : To pathological changes and inducible nitric oxide synthase(iNOS), phosphorylated insulin receptor substrate 1 serine 307(p-IRS1ser 307), phosphorylated protein kinase B serine 473(p-AKTser 473), glycogen synthase kinase-3β(GSK-3β), and gluconeogenic synthase(GS) proteins were observed in the liver of rats under the condition of chronic intermittent hypoxia-replicated oxygen in control. And to explore the role of iNOS/IRS1/AKT/GSK-3β signaling pathway in chronic intermittent hypoxia-induced insulin resistance. Methods : Forty SD rats were randomly divided into a control group(NC group) and an experimental group(CIH group), with 20 rats in each group. The NC group was placed in a normoxic environment for 12 weeks, while the CIH group was first subjected to intermittent hypoxia for 8 weeks, and then resumed normoxic rearing until the 12th week. Fasting blood glucose(FBG) and fasting insulin(FINS) were measured at baseline, week 8 and week 12, and liver tissues were taken for pathology and measurement of iNOS, p-IRS1ser 307, p-AKTser 473, GSK3β and GS levels, to compare the differences between groups. Results: t baseline, there was no significant difference in liver pathology between the two groups, and the observed indexes were not statistically significant(P>0.05); at 8 weeks, compared with the NC group, liver pathology in the CIH group showed significant disorganization of hepatic blood sinusoids and hepatocyte cords, obvious hepatocyte edema, smaller nuclei, increased lymphocyte infiltration, and a small number of fat vacuoles, significantly higher levels of FBG, FINS, insulin resistance index(HOMA-IR), iNOS mRNA, p-IRS1ser 307 protein, GSK-3β protein levels, and decreased p-AKTser 473 protein and GS protein levels, all of which were statistically significant(allP<0.05). IRS1ser 307 protein, GSK-3β protein levels were increased, p-AKTser 473 protein and GS protein levels were decreased, and the differences were statistically significant(allP<0.05); at 12 weeks, no lymphocyte infiltration was seen in the CIH group compared with that of the NC group and fat vacuoles significantly increased, and there was no improvement in the other pathological damage that had already occurred, and the levels of p-AKTser 473 protein significantly increased. AKTser 473 protein level significantly increased, p-IRS1ser 307 protein and GS protein levels were significantly reduced, all of which were statistically significant(allP<0.05), and the rest of the observational indexes were not statistically significant. Pearson′s correlation analysis showed that HOMA-IR of CIH group was significantly positively correlated with the levels of iNOS mRNA, p-IRS1ser 307 protein, and GSK-3β protein at 8 weeks(r=0.874, 0.817,0.872;allP<0.05), and significantly negatively correlated with the levels of p-AKTser 473 protein and GS protein(r=-0.886,-0.879;allP<0.05). Conclusion Chronic intermittent hypoxia can lead to hepatic pathological damage that cannot be reversed even by reoxygenation interventions and may mediate the development of insulin resistance by upregulating the IRS1/AKT/GSK-3β signaling pathway through the upregulation of iNOS mRNA expression.

Objective To investigate the effects of chronic intermittent hypoxia(CIH)and reoxygenation on insulin resistance(IR)and expressions of miR-27a-3p/PPARγ/IRS1/PI3K/AKT in rat skeletal muscle.Methods GEO database was used for screening the differentially expressed miRNAs in CIH,and their target genes were subjected to GO and KEGG enrichment analysis followed by construction of the miRNA-mRNA-pathway regulatory network using Cytoscape.In the animal experiment,48 male SD rats were randomly divided into normoxia group and CIH group(8 weeks of CIH followed by 4 weeks of normoxic recovery).Blood and skeletal muscle samples were collected at baseline,8 weeks,and 12 weeks to evaluate the changes in fasting blood glucose(FBG)and fasting insulin(FINS)levels and muscular pathology.RT-qPCR and Western blotting were used to detect the changes in the expressions of miR-27a-3p,PPARγ,GLUT4,IRS1,p-IRS1,PI3K,p-AKT and AKT in the muscular tissues.Results No muscular miRNA datasets for CIH were available in GEO database,from which only a kidney-related dataset(GSE202480)was obtained,based on which a total of 165 differentially expressed miRNAs were identified.GO/KEGG analysis suggested that these miRNAs were involved in muscular regulation and insulin signaling.The miRNA-mRNA-pathway network highlighted miR-27a-3p as a crucial regulator in the PPAR and PI3K/AKT pathway.In the animal experiment,the rats subjected to CIH for 8 weeks showed significantly increased FBG,FINS,HOMA-IR,and PPARγ levels,loose muscle fiber arrangement,decreased cross-sectional area of the muscle fibers,and lowered expressions of miR-27a-3p,p-IRS1/IRS1,PI3K,and p-AKT/AKT in the skeletal muscles.Conclusion CIH increases IR,causes skeletal muscle pathology,downregulates miR-27a-3p expression,upregulates PPARγ expression,and inhibits IRS1/PI3K/AKT insulin signaling in the skeletal muscles of rats,and these changes can be reversed by reoxygenation.MiR-27a-3p may participate in CIH-induced IR by modulating the PPAR γ/IRS1/PI3K/AKT signaling pathway.

Objective To investigate the effects of chronic intermittent hypoxia(CIH)and reoxygenation on insulin resistance(IR)and expressions of miR-27a-3p/PPARγ/IRS1/PI3K/AKT in rat skeletal muscle.Methods GEO database was used for screening the differentially expressed miRNAs in CIH,and their target genes were subjected to GO and KEGG enrichment analysis followed by construction of the miRNA-mRNA-pathway regulatory network using Cytoscape.In the animal experiment,48 male SD rats were randomly divided into normoxia group and CIH group(8 weeks of CIH followed by 4 weeks of normoxic recovery).Blood and skeletal muscle samples were collected at baseline,8 weeks,and 12 weeks to evaluate the changes in fasting blood glucose(FBG)and fasting insulin(FINS)levels and muscular pathology.RT-qPCR and Western blotting were used to detect the changes in the expressions of miR-27a-3p,PPARγ,GLUT4,IRS1,p-IRS1,PI3K,p-AKT and AKT in the muscular tissues.Results No muscular miRNA datasets for CIH were available in GEO database,from which only a kidney-related dataset(GSE202480)was obtained,based on which a total of 165 differentially expressed miRNAs were identified.GO/KEGG analysis suggested that these miRNAs were involved in muscular regulation and insulin signaling.The miRNA-mRNA-pathway network highlighted miR-27a-3p as a crucial regulator in the PPAR and PI3K/AKT pathway.In the animal experiment,the rats subjected to CIH for 8 weeks showed significantly increased FBG,FINS,HOMA-IR,and PPARγ levels,loose muscle fiber arrangement,decreased cross-sectional area of the muscle fibers,and lowered expressions of miR-27a-3p,p-IRS1/IRS1,PI3K,and p-AKT/AKT in the skeletal muscles.Conclusion CIH increases IR,causes skeletal muscle pathology,downregulates miR-27a-3p expression,upregulates PPARγ expression,and inhibits IRS1/PI3K/AKT insulin signaling in the skeletal muscles of rats,and these changes can be reversed by reoxygenation.MiR-27a-3p may participate in CIH-induced IR by modulating the PPAR γ/IRS1/PI3K/AKT signaling pathway.

Objective:To develop a deep learning model based on multimodal data for glaucoma diagnosis and severity assessment.Methods:A diagnostic test was conducted.A total of 145 normal eyes from 86 participants and 507 eyes with primary open-angle glaucoma from 314 participants were collected at the First Affiliated Hospital of Kunming Medical University from June to December in 2023.Fundus photographs and visual field data were obtained, and glaucoma eyes were divided into three groups based on the mean deviation value of the visual field, namely mild group (154 eyes), moderate group (113 eyes), and severe group (240 eyes).Three convolutional neural network (CNN) models, including DenseNet 121, ResNet 50 and VGG 19, were used to build an artificial intelligence (AI) model.The impact of single-modal and multimodal data on the classification results was evaluated, and the most appropriate CNN network architecture for multimodal data was identified.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of The First Affiliated Hospital of Kunming Medical University (No.2023L93).Written informed consent was obtained from each subject.Results:A total of 652 eyes had both fundus photographs and visual field test results.Images were randomly assigned to training and test datasets in a 4∶1 ratio by using computer random number method.AI models built with different CNN models showed high accuracy, with DenseNet 121 outperforming ResNet 50 and VGG 19 on various effectiveness measures.In the single-modal algorithm using fundus photographs, single-modal algorithm using visual field tests, and multimodal algorithm combining fundus photographs and visual field data, the area under the curve for early glaucoma detection was 0.87, 0.93 and 0.95, respectively.Conclusions:The use of multimodal data enables the development of a highly accurate tool for the glaucoma diagnosis and severity grading.

Objective:To compare the antiosteoporosis effect of conventional treatment and conventional treatment combined with Denosumab after percutaneous kyphoplasty (PKP) for osteoporotic vertebral compression fractures (OVCF).Methods:A retrospective cohort study was conducted to analyze the clinical data of 211 patients with OVCF admitted to the Second Affiliated Hospital of Soochow University from September 2020 to September 2022. All the patients were female, aged 56-90 years [(71.4±8.1)years]. The bone mineral density T-score of the lumbar spine was (-2.6±1.0)SD before operation. Fracture segments included T 1-T 9 in 45 patients, T 10-L 2 in 146, and L 3-L 5 in 69. Of all, 174 patients were treated with single-segment surgery, 25 with two-segment surgery and 12 with surgery involving three or more segments. According to the wishes of the patients, 107 patients were treated with daily oral administration of calcium and active Vitamin D after PKP (conventional treatment group) and 104 patients with Denosumab combined with the conventional treatment after PKP (Denosumab therapy group). The bone mineral density T-scores of the lumbar spine of the two groups were compared before surgery and at the last follow-up. The visual analogue scale (VAS) and Oswestry disability index (ODI) before surgery, at 3 days, 6 months after surgery, and at the last follow-up were evaluated and the refracture rate after surgery was detected. Possible adverse effects after medication during anti-osteoporosis treatment were observed in two the groups. Results:All the patients were followed up for 12-24 months [(13.5±2.0)months]. Before surgery, the bone mineral density T-score of the lumbar spine was (-2.7±1.1)SD in the Denosumab therapy group and (-2.5±0.8)SD in the conventional treatment group ( P>0.05). At the last follow-up, the bone mineral density T-score of the lumbar spine was (-2.1±1.1)SD in the Denosumab therapy group, significantly higher than (-2.5±0.9)SD in the conventional treatment group ( P<0.05). In the Denosumab therapy group, the bone mineral density T-score of the lumbar spine at the last follow-up was significantly increased compared to that before surgery ( P<0.01), while there was no significant difference in the conventional treatment group ( P<0.05). Before surgery and at 3 days after surgery, the VAS scores and ODI values were (8.5±0.9)points, (2.8±0.8)points, 48.7±4.8 and 25.6±4.0 in the Denosumab therapy group, which was not statistically different from those in the conventional treatment group [(8.5±1.3)points and (2.8±0.9)points, 47.9±7.0 and 25.9±3.7] ( P>0.05). At 6 months after surgery and at the last follow-up, the VAS scores and ODI values were (2.2±0.8)points, (1.7±0.8)points, 24.2±3.6 and 23.2±4.1 in the Denosumab therapy group, significantly lower than those of the conventional treatment group [(2.8±0.9)points, (2.8±1.1)points, 26.4±3.2 and 27.3±4.0] ( P<0.01). The VAS scores at each time point after surgery in both groups decreased significantly compared with those before surgery ( P<0.05). The VAS scores continued to decrease after surgery in the Denosumab therapy group ( P<0.05), while no significant difference was found among those at different time points in the conventional treatment group ( P>0.05). The ODI values at each time point after surgery in both groups significantly decreased compared to those before surgery ( P<0.05). The ODI values continued to decrease after surgery in the Denosumab therapy group ( P<0.05), while in the conventional treatment group, no significant difference was found between those at 6 months after surgery and those at 3 days after surgery ( P>0.05) and they were improved at the last follow-up compared with those at 3 days after surgery ( P<0.05). The refracture rate after surgery was 6.7% (7/104) in the Denosumab therapy group, significantly lower than 16.8% (18/107) in the conventional treatment group ( P<0.05). No serious complications were observed during the antiosteoporosis period in either group. Conclusion:Compared with daily oral administration of Calcium and active Vitamin D after PKP, the conventional treatment combined with Denosumab after PKP can effectively increase the bone density, relieve pain continuously, improve functional restoration, and reduce the risk of refracture in OVCF patients.

Tumor metastasis depends on the dynamic balance of the actomyosin cytoskeleton. As a key component of actomyosin filaments, non-muscle myosin-IIA disassembly contributes to tumor cell spreading and migration. However, its regulatory mechanism in tumor migration and invasion is poorly understood. Here, we found that oncoprotein hepatitis B X-interacting protein (HBXIP) blocked the myosin-IIA assemble state promoting breast cancer cell migration. Mechanistically, mass spectrometry analysis, co-immunoprecipitation assay and GST-pull down assay proved that HBXIP directly interacted with the assembly-competent domain (ACD) of non-muscle heavy chain myosin-IIA (NMHC-IIA). The interaction was enhanced by NMHC-IIA S1916 phosphorylation via HBXIP-recruited protein kinase PKCβII. Moreover, HBXIP induced the transcription of PRKCB, encoding PKCβII, by coactivating Sp1, and triggered PKCβII kinase activity. Interestingly, RNA sequencing and mouse metastasis model indicated that the anti-hyperlipidemic drug bezafibrate (BZF) suppressed breast cancer metastasis via inhibiting PKCβII-mediated NMHC-IIA phosphorylation in vitro and in vivo. We reveal a novel mechanism by which HBXIP promotes myosin-IIA disassembly via interacting and phosphorylating NMHC-IIA, and BZF can serve as an effective anti-metastatic drug in breast cancer.

Objective:To investigate the risk factors of high intraocular pressure (IOP) after femtosecond laser in situ keratomileusis (FS-LASIK) in patients with high myopia, and construct and verify nomogram model.Methods:A retrospective clinical study. From January 2019 to January 2021, 327 patients (654 eyes) with high myopia treated with FS-LASIK in the Department of Ophthalmology of the 910th Hospital of the People's Liberation Army Coalition Security Force were included in the study. The patients were categorized into high IOP group and non-high IOP group according to whether high IOP occurred after surgery, which were 60 cases and 120 eyes (18.35%, 60/327) and 267 cases and 534 eyes (81.65%, 267/327), respectively. The clinical data of patients in the two groups were analyzed and observed, and the indicators with differences were subjected to one-way and multifactorial logistic regression analyses, and the results of the regression analyses were visualized to obtain the column line graphs using R3.5.3 software, and the accuracy of the column line graphs was verified by the consistency index (C-index), the calibration curves, and the subject's work characteristic curves (ROC curves).Results:Comparison of the number of cases of affected corneal thickness ( χ2=7.424), corneal curvature ( χ2=9.849), glucocorticoid treatment ( χ2=7.222), intraoperative IOP fluctuation ( χ2=11.475), corneal hysteresis ( χ2=6.368), and the incidence of intraoperative complications ( χ2=6.673) in the hypertensive IOP group and the nonvisualized IOP group were statistically significant ( P<0.05). Binary logistic regression analysis showed that corneal thickness >450 μm, corneal curvature≤38 D, glucocorticoid treatment, intraoperative IOP fluctuation, corneal hysteresis ≤8.0 mm Hg (1 mm Hg=0.133 kPa), and intraoperative complications were the risk factors for the occurrence of high IOP after FS-LASIK surgery in patients with high myopia ( P<0.05). The C-index of the column-line graph prediction model based on this was 0.722 (95% confidence interval 0.684-0.760), the calibration curve and the ideal curve were basically the same, and the area under the ROC curve was 0.709. Conclusions:Corneal thickness> 450 μm, keratometric curvature ≤38 D, glucocorticoid treatment, intraoperative fluctuation of intraocular pressure, and corneal hysteresis ≤8.0 mm Hg are the risk factors for the development of hyperopic IOP in highly risk factors for the development of high IOP after FS-LASIK surgery in myopic patients. The column-line diagram model constructed on the basis of the risk factors hava good accuracy.

Objective:To learn about the levels of 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) in bone tissue of rats with different types of skeletal fluorosis and analyze their correlation.Methods:Thirty 4-week-old SPF grade healthy SD rats were selected. After adaptive feeding for 1 week, the rats were divided into control group (4 ml·kg -1·bw deionized water + standard maintenance diet), osteosclerosis group [20 mg·kg -1·bw sodium fluoride (NaF) + standard maintenance diet], and osteoporosis/osteomalacia group (20 mg·kg -1·bw NaF + low-calcium and low-protein partial diet) according to their body weight (100 - 120 g) by random number table method, with 10 rats in each group, half male and half female; gavaged 6 days each week and the experimental period was 5 months. At the end of the experiment, samples of rat heart blood and lower limb femur were collected. The contents of serum methyl donor S-adenosylmethionine (SAM) and its metabolite S-adenosylhomocysteine (SAH) in serum, and the levels of 5-mC and 5-hmC in bone tissue were measured by enzyme-linked immunosorbent assay (ELISA). Western blot was used to determine the expression of DNA methyltransferase (DNMTs) and DNA hydroxymethylase (TETs) in bone tissue of rats. The correlation between serum SAM content, SAM/SAH ratio and bone tissue 5-mC level, and between the bone tissue 5-mC level and 5-hmC level was analyzed. Results:Serum SAM [11.03 (7.06, 18.63), 3.96 (2.32, 9.09), 3.91 (2.35, 4.46) nmol/L], SAH content [(4.69 ± 0.55), (5.41 ± 1.13), (13.90 ± 1.09) ng/L], SAM/SAH ratio [2.58 (1.54, 4.12), 0.62 (0.52, 1.69), 0.14 (0.13, 0.15)] and bone tissue 5-mC [103.39 (97.37, 109.35), 52.50 (50.19, 68.13), 55.03 (49.97, 59.57) ng/L], 5-hmC levels [(32.61 ± 8.84), (56.96 ± 8.48), (20.34 ± 6.22) ng/L] in the control group, osteosclerosis group and osteoporosis/osteomalacia group were compared, and the differences were statistically significant beween three groups ( H/ F = 12.81, 284.24, 21.85, 19.37, 55.23, P < 0.01). Compared with the control group, the content of SAM, the ratio of SAM/SAH, the level of 5-mC in the osteosclerosis group and osteoporosis/osteomalacia group, and the level of 5-hmC in the osteoporosis/osteomalacia group were lower ( P < 0.05), while the content of SAH in the osteoporosis/osteomalacia group and the level of 5-hmC in the osteosclerosis group were higher ( P < 0.05). Compared with the osteosclerosis group, the content of SAH in the osteoporosis/osteomalacia group was higher, while the ratio of SAM/SAH and the level of 5-hmC were lower ( P < 0.05). Western blot showed that there were statistically significant differences in the expression levels of DNMT1, DNMT3A, DNMT3B, TET1 and TET2 protein in bone tissue of rats in the control group, osteosclerosis group, and osteoporosis/osteomalacia group ( F = 285.45, 345.58, 239.83, 311.52, 318.24, P < 0.001). Among them, the expression levels of DNMT1, DNMT3A and DNMT3B protein in the osteosclerosis group and osteoporosis/osteomalacia group were lower than those in the control group, and the expression levels of DNMT1, DNMT3A and DNMT3B protein in the osteosclerosis/osteomalacia group were lower than those in the osteosclerosis group ( P < 0.05); the expression levels of TET1 and TET2 protein in osteosclerosis group were higher than those in the control group and osteoporosis/osteomalacia group, and the expression levels of TET1 and TET2 protein in the osteoporosis/osteomalacia group were lower than those in the control group ( P < 0.05). The results of Spearman rank correlation analysis showed that the content of SAM and the ratio of SAM/SAH in the control group, osteosclerosis group and osteoporosis/osteomalacia group were positively correlated with the level of 5-mC in bone tissue ( rs = 0.89, 0.92, 0.81, 0.73, 0.87, 0.73, P < 0.05). The levels of 5-mC and 5-hmC in bone tissue of rats in each group were negatively correlated ( rs = - 0.69, - 0.68, - 0.72, P < 0.05). Conclusions:The level of 5-mC in bone tissue of osteosclerotic fluorosis rats is low, and the level of 5-hmC is high, while those of osteoporosis/osteomalacia fluorosis rats are lower. The difference of 5-mC level in bone tissue of rats with different types of skeletal fluorosis is not significant, which may be related to the difference of 5-hmC level in bone tissue.