BACKGROUND:Thermoresponsive hydrogels are widely used in bone tissue engineering due to their structural similarity to extracellular matrix and their intelligent temperature sensitivity.OBJECTIVE:To explain the mechanism of temperature-responsive hydrogels producing sol-gel phase transitions,classify them based on their sources,and summarize the applications of various temperature-responsive hydrogels in bone tissue engineering.METHODS:The first author searched for relevant literature on CNKI and PubMed databases from 2000 to 2024,using search terms"hydrogel,thermosensitive hydrogel,bone repair,bone regeneration,bone tissue engineering"in Chinese and English.A total of 70 eligible articles were finally selected for review.RESULTS AND CONCLUSION:The temperature-sensitive mechanism of thermosensitive hydrogels can be divided into negative sensitive and positive sensitive according to different reactions.Its composition is mainly divided into natural polymer and synthetic polymer.Current research has found that in addition to the traditional way of using temperature-sensitive hydrogels as scaffold materials for bone tissue engineering,3D printed scaffolds are also gradually emerging.In addition,thermosensitive hydrogels can also be used in 3D cell culture and drug slow release due to their own characteristics.At present,the development of thermosensitive hydrogels is not perfect enough.There are still problems such as the inability to accurately control the phase transition temperature,sustained release rate,low mechanical strength,and low biodegradability.Therefore,developing thermosensitive hydrogels with more stable properties is still a problem that we should solve at present.

BACKGROUND:Thermoresponsive hydrogels are widely used in bone tissue engineering due to their structural similarity to extracellular matrix and their intelligent temperature sensitivity.OBJECTIVE:To explain the mechanism of temperature-responsive hydrogels producing sol-gel phase transitions,classify them based on their sources,and summarize the applications of various temperature-responsive hydrogels in bone tissue engineering.METHODS:The first author searched for relevant literature on CNKI and PubMed databases from 2000 to 2024,using search terms"hydrogel,thermosensitive hydrogel,bone repair,bone regeneration,bone tissue engineering"in Chinese and English.A total of 70 eligible articles were finally selected for review.RESULTS AND CONCLUSION:The temperature-sensitive mechanism of thermosensitive hydrogels can be divided into negative sensitive and positive sensitive according to different reactions.Its composition is mainly divided into natural polymer and synthetic polymer.Current research has found that in addition to the traditional way of using temperature-sensitive hydrogels as scaffold materials for bone tissue engineering,3D printed scaffolds are also gradually emerging.In addition,thermosensitive hydrogels can also be used in 3D cell culture and drug slow release due to their own characteristics.At present,the development of thermosensitive hydrogels is not perfect enough.There are still problems such as the inability to accurately control the phase transition temperature,sustained release rate,low mechanical strength,and low biodegradability.Therefore,developing thermosensitive hydrogels with more stable properties is still a problem that we should solve at present.

Objective:To investigate the protective effect and mechanism of Icaritin Ⅱ (ICAⅡ) on bladder in radiation cystitis model.Methods:A total of 18 10-week-old male SD rats were selected from July 2021 to March 2022 and divided into control group, model group and treatment group by random number table method, with 6 cases in each group. Model group and treatment group were given a single dose of 20 Gy X-ray irradiation in the pelvic area. 24 h after irradiation, the treatment group was given ICAⅡ 4.5 mg/(kg·d) gavage, while the control group and model group were given the same volume of solvent (10% anhydrous ethanol, 20% isopropyl alcohol, 30% polyethylene glycol and 40% deionized water) gavage for 4 consecutive weeks. Drug eluting for 1 week. The bladder volume and leakage point pressure of the three groups of rats were measured by multi-conducting physiological apparatus, and the bladder function was evaluated. HE staining, Masson staining, ELISA, TUNEL staining and western blotting were performed on the bladder samples of the three groups of rats. The pathological changes (thickness of bladder mucosa, ratio of smooth muscle to collagen fiber), oxidative stress level (superoxide dismutase SOD, malondialdehyde), apoptosis rate, protein levels of inflammatory factors (IL-6, NF-kB) and anti-oxidative stress signaling pathway factors (Nrf2, HO-1) of the three groups of rats were compared.Results:After 4 weeks of modeling, in the model group, the bladder volume [(1.01±0.12)ml vs. (1.58±0.21)ml, P=0.001], the bladder leakage point pressure [(38.79±4.12) cmH 2O (1 cmH2O=0.098 kPa)vs.(60.59±3.81) cmH 2O, P=0.001], the ratio of smooth muscle of bladder wall to collagen fiber [1.78±0.17 vs.3.15±0.57, P=0.001], SOD[(6.31±0.73) U/mg vs.(14.67±1.04) U/mg, P=0.001] were lower than the control group, and the differences were statistically significant. In the model group, the thickness of bladder mucosa [(47.33±1.78)μm vs.(20.83±2.33)μm, =, P=0.001], malondialdehyde [(1.01±0.13) nmol/mg vs.(0.49±0.03) nmol/mg, P=0.001], IL-6 (0.87±0.11 vs. 0.33±0.10, P=0.001), NF-kB (0.71±0.14 vs. 0.29±0.07, P=0.001), apoptosis rate [(11.60±3.04)% vs. (3.91±1.40)%, P=0.007] was higher than the control group, and the differences were statistically significant. In the treatment group, the bladder volume [(1.27±0.13)ml, P=0.030], bladder leakage point pressure [(47.83±2.50)cmH 2O, P=0.004], smooth muscle to collagen fiber ratio (2.78±0.68, P=0.015), SOD[(10.48±0.85) U/mg, Compared with model group, bladder mucosa thickness [(31.94±3.20)μm, P=0.001], malondialdehyde [(0.64±0.09) nmol/mg, P=0.001], IL-6 (0.69±0.11, P=0.035), NF-kB (0.45±0.06, P=0.002) and apoptosis rate [(6.05±0.60)%, P=0.030] were lower than those in model group. The protein expression level of Nrf2 in model group (0.73±0.08 vs. 0.58±0.11, P=0.023) was higher than that in control group, but there was no significant difference in the protein expression level of downstream antioxidant factor HO-1 (0.50±0.14 vs. 0.35±0.06, P=0.060). Nrf2 protein expression level (0.88±0.03, P=0.027) and HO-1 expression level (0.68±0.07, P=0.026) in treatment group were higher than those in model group. Conclusion:ICAⅡ can reduce radiation cystitis injury, and its mechanism may be related to anti-oxidative stress and reducing inflammation.

[Abstract] Objective:ToinvestigatetheroleofmiR-125a-5pininducingthegefitinib(Gef)-resistance of non-small cell lung carcinoma (NSCLC) cells and its possible mechanism. Methods: Human NSCLC drug-resistant cell line A549/GR and NSCLC cell line A549 were chosen for this study. miR-125a-5p mimic, miR-125a-5p inhibitor, pcDNA3.1-APAF1 and empty vector pcDNA3.1 were transfected into A549/GR cells. The expression level of miR-125a-5p in cell lines was detected by qPCR. MTT, Transwell and Flow cytometry were used to detect the effects of Gef on proliferation, migration and apoptosis of cell lines, respectively. The targeting relationship between miR-125a-5p and APAF1 (apoptotic peptidase activating factor 1) was verified by Dual-luciferase reporter gene system. In addition, the expression of APAF1 protein in A549/GR cells was detected by Western blotting. The expression levels of caspase-3 and caspase-9 were assessed by colorimetry. Results: Expression level of miR-125a-5p was upregulated significantly in Gefresistant A549/GR cells (P<0.01). AndtheinfluencesofGefonA549/GRcellswereenhancedby knockdown of miR-125a-5p, including inhibiting cell proliferation and migration (all P<0.05) and inducing apoptosis (P<0.01). Dual luciferase reporter gene assay confirmed that miR-125a-5p targeted APAF1 and negatively regulated its expression. Furthermore, by targetedly downregulating APAF1, miR-125a-5p alleviated the inhibition of proliferation and migration (all P<0.05) and promotion of apoptosis (P<0.05) of A549/GR cells caused by Gef, and attenuated Gef-induced upregulation of apoptosis-related proteins caspase-3 and caspase-9 (all P<0.05). Conclusion: miR-125a-5p promotes Gef-resistance of A549/GR cells, and the underlying mechanisms are promotion of proliferation, migration and inhibition of apoptosis of non-small cell lung cancer cells by targetingAPAF1.

Objective: To understand the characteristics and changes of the incidence of amoebic dysentery in China during 2015-2018, explore the causes of high incidence in some areas and provide a data base for the development of national prevention and control strategies and measures. Methods: Data were collected from the infectious disease reporting management information system from Chinese Disease Control and Prevention. To understand the seasonal, population and area distributions of amoebic dysentery, descriptive epidemiological method and software SPSS 16.0 were used to analyze the amoebic dysentery data. Results: A total of 4 366 amoebic dysentery cases were reported without death in China during 2015-2018. The reported average annual incidence was 0.08/100 000, and the overall proportion of laboratory confirmed cases was 68.23%(2 979/4 366). Amoeba dysentery mainly occurred during May to October. One seasonal peak was observed in 2015 and 2017 (July and June, respectively), and two seasonal peaks were observed in 2016 and 2018 (June and October). The patients were mainly children aged under 5 years (42.28%, 1 846/4 366), and the incidence rate decreased with age in children aged under 10 years. Of these, children under 1 years of age had the highest incidence rate (1.28/100 000). The number of cumulative reported cases in Guangxi, Henan, Guangdong, Heilongjiang and Jiangxi provinces ranked top five from 2015-2018, accounting for 64.50% (2 816/4 366) of the total. The cumulative cases in Dongxing county, Guangxi, in Suixian county, Henan and in Ranghulu district, Heilongjiang, respectively accounted for more than 50.00% of the total number of cases in their provinces. Conclusions The incidence rate of amoebic dysentery reported in China during 2015-2018 showed a decreasing trend, with a higher incidence in children under 5 years old and a higher number of cases in some areas. It is suggested to further investigate and analyze the diagnosis and reporting of amoeba dysentery in key areas and promote the update of the diagnostic standards for amoeba dysentery.