BACKGROUND:Chemokines can promote (MSCs) the secretion of vasoactive factors from mesenchymal stem cel s (MSCs) through paracrine mechanism, which have important role in accelerating angiogenesis. OBJECTIVE:Under the high glucose environment, to the effect of the supernatant of MSCs stimulated by chemokine (C-X-C motif) ligand 8 (CXCL-8) on human umbilical vein endothelial cel s (HUVECs), and to analyze the mechanism of Sonic Hedgehog signaling pathway in the stimulation of CXCL-8 on MSCs. METHODS:Under the high glucose environment, the MSCs supplemented with 100μg/L CXCL-8 were set as CXCL-8 group;the MSCs that were preprocessed with 5μmol/L octyl maleimide for 45 minutes and then stimulated with 100μg/L CXCL-8 were as Shh inhibitor group;the MSCs that were routinely cultured in a high-glucose medium were as control group. The cel supernatant of each group was extracted as conditioned medium (CM) to culture HUVECs, respectively, and these cel s were referred to as CXCL-8 CM group, Shh inhibitor CM group, and control CM group, respectively. Cel counting kit-8, cel scratch and Transwel chamber tests were used to observe the effect of each CM on HUVEC proliferation, apoptosis and chemotaxis. By establishment of a diabetic skin ulcer model in C57BL/6J mice, the CM of each group was used to treat the mouse model to confirm the effects of CXCL-8 stimulated MSCs CM on HUVEC homing and ulcer healing. RESULTS AND CONCLUSION:(1) The experimental results in vitro:compared with the control CM group, CXCL-8 CM group significantly promoted the proliferation of HUVECs, and decreased the apoptosis of HUVECs, the closure rate and migration rate of HUVECs were significantly increased (P<0.01 or P<0.01), and the levels of vascular endothelial growth factor and epidermal growth factor were significantly increased (P<0.01 or P<0.01). Compared with CXCL-8 CM group, however, the above results in the Shh inhibitor CM group showed reverse changes (P<0.01). (2) The experimental results in vivo:compared with the MSCs CM group and Shh inhibitor CM group, the healing effect of diabetic skin ulcer and the number of HUVECs labeled by green fluorescent protein in the CXCL-8 CM group were significantly increased (P<0.01). To conclude, these findings indicate that CXCL-8 stimulated MSCs secrete paracrine factors, vascular endothelial growth factor and epidermal growth factor, through the Sonic Hedgehog signaling pathway under the high glucose environment, which enhance the homing ability of HUVECs.

Objective To evaluate the application of Web problem-based learning (WPBL) mode of respiratory system integration curriculum.Methods Experimentclasses 1 and 2 of the 2014 grades of the Qiqihar Medical University were divided into control group(48 students) and experiment group (48 students).Traditional PBL teaching was conducted in control group:the contents of the case were printed and discussed with the material of each class.WPBL teaching was conducted in experiment group:autonomous learning before class,showing cases by Video,asking questions and discussion in group and reporting results in class.The teaching effect was evaluated by PBL evaluation form,questionnaire and final grade.SSPS 19.0 statistical software was used for data analysis and measurement.T test was conducted among groups.Counting data were tested by Chi-square and the results were expressed as percentage.Results The students in the experiment group were better than those of control groupin the aspects of contents understanding,course interest,clinical thinking ability,classroom atmosphere and the course attitude.The scores of PBL (16.65 ±2.82),experiment exam (8.21 ±0.44) and final grade(76.77 ± 12.31) in the experiment group were higher than those in the control group.There are statistical differences in two groups (P＜0.05).Conclusions WPBL teaching can improve students'learning interest,clinical thinking ability and improve the teaching quality of respiratory integration curriculum.

Objective To discuss the application of blending learning based on MOOC in Histology and Embryology, so as to improve students' learning effectiveness. Methods Nursing undergraduates in class one of 2017 grade were randomly selected as experimental group (n=47) , and nursing undergraduates in class two as control group (n=48), with blending learning and traditional teaching model adopted, respec-tively. SPSS 19.0 was applied to processing the data and T test were used to compare the results of the final exam of this course and the evaluation scale of students' independent learning ability in two groups. Results The experimental scores [(24.22±5.08) vs. (18.49±4.65)], paper test scores [(52.37±6.24) vs. (47.15± 5.99)], and total score [(76.61±7.22) vs. (62.83±7.36)], which shows the scores of experimental group were statistically higher than those of the control group. According to the evaluation scale of students' inde-pendent learning ability, the self-learning ability of the experimental group was better than that of the control group, with significant differences (P<0.05). Conclusion Blending learning can be applied to the teaching of Histology and Embryology, which can effectively improve learning quality, with satisfactory teaching effects to both teachers and students.

Objective:To explore the application effect of online-offline mixed teaching mode in the teaching of histology and embryology.Methods:Two classes of students majoring in psychiatry from Batch 2020 were randomized into experimental group ( n = 100), and two classes of students majoring in general practice in 2020 grade were randomized into the control group ( n = 99). The online-offline mixed teaching mode was used in the experimental group, while a traditional teaching mode was used in the control group. The online test scores, final scores and questionnaire satisfaction of the two groups of students were evaluated on the teaching effect. All data were statistically processed by SPSS 19.0, and the comparison between groups was performed by t test. Results:The online test scores of the experimental group [(8.55±1.18) vs. (6.33±0.91)] and final scores [(85.56±3.32) vs. (72.24±2.71)] were significantly higher than those of the control group ( P < 0.05). Compared with the control group, the experimental group's satisfaction scores of the online-offline mixed teaching mode were significantly higher in students' learning interest, learning autonomy, time management ability, teamwork, interactive communication, knowledge understanding and memory ability ( P < 0.05). Conclusion:The online-offline mixed teaching mode can improve the histology and embryology teaching effect and promote the students' interest in learning and autonomous learning ability.