ObjectiveThis paper aims to investigate the effects of icariin on spermatogenesis in mice with exercise-induced fatigue and explore the underlying mechanisms. MethodsICR male mice were screened by swimming and randomly divided into normal group， model group， vitamin C group， icariin groups with low， medium， and high doses， and medium-dose icariin+N-nitro-L-arginine methyl ester （L-NAME） group， with 10 mice per group. Except for the normal group， all the other groups underwent weighted swimming training to establish an exercise-induced fatigue model. No gavage was administered during the first two weeks of the weighted training. From week three to four， the icariin groups with low， medium， and high doses received 0.03， 0.06， and 0.12 g·kg^-1 icariin via gavage， respectively. The vitamin C group received 0.2 g·kg^-1 vitamin C. The L-NAME group received 0.06 g·kg^-1 icariin and 0.01 g·kg^-1 L-NAME via intraperitoneal injection. The normal and model groups received equivalent physiological saline. After the experiment， body weight and the last exhaustive swimming time were recorded. Blood urea nitrogen （BUN）， lactate （LA）， lactate dehydrogenase （LDH）， malondialdehyde （MDA）， testicular testosterone （T）， testicular Ca²⁺/Mg²⁺-adenosine triphosphatase （ATPase） （micro-assay）， and the levels of testicular cyclic guanosine monophosphate （cGMP） were measured by using kits. Sperm CD46 levels were detected by flow cytometry. Testicular seminiferous tubules were observed via hematoxylin-eosin （HE） staining， and the testicular morphometric score （TMS） was used to evaluate the spermatogenic function. Protein expression of regucalcin （RGN， SMP30）， cGMP-dependent protein kinase 1 （PKG）， and cGMP-dependent protein kinase anchoring protein （GKAP1） was detected by Western blot. Testicular regucalcin expression was examined by immunofluorescence （IF）. The epididymal sperm quality of mice was observed under a microscope. Fluorescence-stained sections of stimulated by retinoic acid gene 8 （STRA8）， synaptonemal complex protein 3 （SCP3）， and transition protein 1（TNP1） in testicular seminiferous tubules were assessed by immunohistochemistry （IHC）. ResultsCompared with the normal group， the model group showed decreased body weight and exhaustive swimming time （P<0.01）， significantly increased fatigue markers （LA， LDH， and BUN） and lipid peroxidation product MDA （P<0.01）， reduced testicular RGN， PKG， GKAP1， testosterone， Ca²⁺/Mg²⁺-ATPase， and cGMP levels （P<0.01）， decreased sperm motility， sperm count， and TMS scores， and downregulated the expression of STRA8， SCP3， and TNP1. Compared with the model group， the icariin group with high dose exhibited increased exhaustive swimming time （P<0.01）， reduced LA， LDH， BUN， and MDA levels （P<0.01）， elevated superoxide dismutase （SOD） （P<0.01）， upregulated testicular RGN， PKG， GKAP1， testosterone， Ca²⁺/Mg²⁺-ATPase， and cGMP levels （P<0.01）， improved sperm motility， sperm count， and TMS scores， and enhanced STRA8， SCP3， and TNP1 expression. Compared with the L-NAME group， the icariin group with medium dose showed increased expression of STRA8， SCP3， and TNP1 in the testicular tissue （P<0.01） and elevated cGMP and GKAP1 levels （P<0.01）. ConclusionExercise-induced fatigue reduces the expression of RGN and cGMP/PKG/GKAP1 in mice， thereby causing abnormal spermatogenesis and impairing reproductive function in mice. Icariin ameliorates spermatogenic dysfunction in exercise-induced fatigue mice by promoting the expression of RGN and cGMP/PKG/GKAP1， thereby mitigating the damage of exercise-induced fatigue to the reproductive system.

ObjectiveThis paper aims to investigate the effects of icariin on spermatogenesis in mice with exercise-induced fatigue and explore the underlying mechanisms. MethodsICR male mice were screened by swimming and randomly divided into normal group， model group， vitamin C group， icariin groups with low， medium， and high doses， and medium-dose icariin+N-nitro-L-arginine methyl ester （L-NAME） group， with 10 mice per group. Except for the normal group， all the other groups underwent weighted swimming training to establish an exercise-induced fatigue model. No gavage was administered during the first two weeks of the weighted training. From week three to four， the icariin groups with low， medium， and high doses received 0.03， 0.06， and 0.12 g·kg^-1 icariin via gavage， respectively. The vitamin C group received 0.2 g·kg^-1 vitamin C. The L-NAME group received 0.06 g·kg^-1 icariin and 0.01 g·kg^-1 L-NAME via intraperitoneal injection. The normal and model groups received equivalent physiological saline. After the experiment， body weight and the last exhaustive swimming time were recorded. Blood urea nitrogen （BUN）， lactate （LA）， lactate dehydrogenase （LDH）， malondialdehyde （MDA）， testicular testosterone （T）， testicular Ca²⁺/Mg²⁺-adenosine triphosphatase （ATPase） （micro-assay）， and the levels of testicular cyclic guanosine monophosphate （cGMP） were measured by using kits. Sperm CD46 levels were detected by flow cytometry. Testicular seminiferous tubules were observed via hematoxylin-eosin （HE） staining， and the testicular morphometric score （TMS） was used to evaluate the spermatogenic function. Protein expression of regucalcin （RGN， SMP30）， cGMP-dependent protein kinase 1 （PKG）， and cGMP-dependent protein kinase anchoring protein （GKAP1） was detected by Western blot. Testicular regucalcin expression was examined by immunofluorescence （IF）. The epididymal sperm quality of mice was observed under a microscope. Fluorescence-stained sections of stimulated by retinoic acid gene 8 （STRA8）， synaptonemal complex protein 3 （SCP3）， and transition protein 1（TNP1） in testicular seminiferous tubules were assessed by immunohistochemistry （IHC）. ResultsCompared with the normal group， the model group showed decreased body weight and exhaustive swimming time （P<0.01）， significantly increased fatigue markers （LA， LDH， and BUN） and lipid peroxidation product MDA （P<0.01）， reduced testicular RGN， PKG， GKAP1， testosterone， Ca²⁺/Mg²⁺-ATPase， and cGMP levels （P<0.01）， decreased sperm motility， sperm count， and TMS scores， and downregulated the expression of STRA8， SCP3， and TNP1. Compared with the model group， the icariin group with high dose exhibited increased exhaustive swimming time （P<0.01）， reduced LA， LDH， BUN， and MDA levels （P<0.01）， elevated superoxide dismutase （SOD） （P<0.01）， upregulated testicular RGN， PKG， GKAP1， testosterone， Ca²⁺/Mg²⁺-ATPase， and cGMP levels （P<0.01）， improved sperm motility， sperm count， and TMS scores， and enhanced STRA8， SCP3， and TNP1 expression. Compared with the L-NAME group， the icariin group with medium dose showed increased expression of STRA8， SCP3， and TNP1 in the testicular tissue （P<0.01） and elevated cGMP and GKAP1 levels （P<0.01）. ConclusionExercise-induced fatigue reduces the expression of RGN and cGMP/PKG/GKAP1 in mice， thereby causing abnormal spermatogenesis and impairing reproductive function in mice. Icariin ameliorates spermatogenic dysfunction in exercise-induced fatigue mice by promoting the expression of RGN and cGMP/PKG/GKAP1， thereby mitigating the damage of exercise-induced fatigue to the reproductive system.

Objective:To evaluate the effectiveness of anti-G straining maneuver (AGSM) in pilots by surface electromyography (sEMG), and to explore the relationships between characteristics of sEMG and anti-G endurance in pilots.Methods:Thirty-eight male high-performance fighter pilots who completed the human centrifuge test at the Air Force Medical Center were selected. Among them, 25 completed the 8.0 G for 10 s anti-G endurance test and 13 completed the 9.0 G for 10 s anti-G endurance test. The sEMG tester was used to keep track of the changes of sEMG in rectus abdominis, rectus femoris, anterior tibial and gastrocnemius muscles while pilots were engaged in AGSM. The anti-G endurance was evaluated according to the changes of visual fields and consciousness. The pilots were divided into 3 groups: the good vision and consciousness group, peripheral visual field narrowing group and endurance endpoint group. The differences in the integral electromyogram (iEMG), mean power frequency (MPF) and muscle input rates between the 3 groups were investigated.Results:A total of 25 pilots completed the 8.0 G for 10 s anti-G endurance test. Among them, 8 (32.0%) were in the good vision and consciousness group, 13 (52.0%) in the peripheral visual field narrowing group and 4 (16.0%) reached the endurance endpoint. Among the 13 pilots who completed the 9.0 G for 10 s anti-G endurance test, 3 (23.1%) were in the good vision and consciousness group, 6 (46.1%) in the peripheral visual field narrowing group, and 4 (30.8%) in the endurance endpoint group. The results of sEMG showed that the iEMG values of the anterior tibialis muscle in pilots under the 9.0 G for 10 s load were significantly different across endurance groups ( H=7.54, P=0.023), and that the iEMG values of the tibialis anterior muscle in the good vision and consciousness group were higher than those in the endurance endpoint group ( P=0.036). The negative slopes of MPF for the rectus abdominis, rectus femoris, anterior tibialis, and gastrocnemius muscles were higher in the good vision and consciousness group than in the other 2 groups, but the differences were not statistically significant ( P>0.05). During the 8.0 G for 10 s anti-G endurance test, there were significant differences in lower limb muscle contribution rates between the 3 groups ( F=4.19, P=0.029). The endurance endpoint group exhibited a lower contribution rate than the good vision and consciousness group ( P=0.025). During the 9.0 G for 10 s anti-G endurance test, there were significant differences in tibialis anterior muscle contribution rates between the 3 groups ( F=4.16, P=0.049). The endurance endpoint group demonstrated a lower contribution rate than the good vision and consciousness group ( P=0.049). Conclusions:The full and balanced activation of abdominal muscles and lower limb muscles, especially the effective mobilization of calf muscles, plays a pivotal role in improving pilots′ AGSM efficiency in high G environments.

Objective:To find out whether the performance of a China-made high performance human centrifuge can satisfy the need of high G training by conducting physiological experiments.Methods:The dynamic physical performance of the anti-G equipment with the human centrifuge was tested before 5 subjects underwent the gradual-onset rate (GOR) run and rapid onset rate (ROR) run experiments. The G onset rate of GOR was 0.1 G/s. The relaxed G-tolerance under GOR (GOR tolerance 1) and the anti-G straining maneuver aided G-tolerance under GOR (GOR tolerance 2) were tested respectively. The G onset rate of ROR was 3 G/s, and the closed-loop mode and pre-programed mode were employed respectively. The closed-loop mode involved 5 G 10 s and 8 G 10 s, where the subjects were required to manipulate the joystick to ensure that the real-time curve of the load matched the target curve. In the pre-programmed mode, the subjects were exposed to 8 G 10 s passively, without any operation requirements. A subjective evaluation form was filled out by subjects after the experiments, in which the 14 indexes for evaluation were about the gondola facilities and environment, running processes, medical monitoring and overall assessment.Results:Both the oxygen mask and anti-G suit achieved full pressurization within 2.0 s. The GOR tolerance 1 was [4.0(3.8, 4.6)] G while the GOR tolerance 2 was (6.2±0.5) G, suggesting a statistically significant difference ( Z=-2.63, P=0.008). The HP anti-G straining maneuver effect was (2.0±0.6) G. All the 5 subjects finished the 5 G 10 s experiment in a closed-loop mode. Three of them attempted 8 G 10 s in the closed-loop mode (1 subject achieved only 7.6 G peak acceleration, and the other 2 achieved full 8 G 10 s exposure), while the remaining 2 completed the 8 G 10 s in the pre-programmed mode. In the closed-loop mode, it was found that the stick force was too strong, the guiding G and real time G curve were not easy to distinguish for some of the subjects because the curve colors were similar, and that the subjects could not see the G curves clearly in case of a grayout. Both seat comfort and the voice quality of communication got the highest subjective assessment score [5.0(4.0, 5.0)] while the sensation of tumble got the lowest score (2.8±0.8). The median or mean scores of other subjective evaluation indexes ranged from 3.0 to 4.6 points. The overall score of subjective assessment was [4.0(3.5, 4.0)] points. Conclusions:The China-made high performance human centrifuge can meet the requirements of 8.0 G high G training, which can be made more effective and comfortable if the strong stick force and feeling of tumble during stop running are overcome.

Objective To examine the effect of the demethylating agent 5-aza-2'-deoxycytidine(5-Aza-CdR)on pericyte-myofibroblast transition(PMT)in primary rat renal myofibroblasts.Methods Rat primary renal myofibroblasts were treated with 5-Aza-CdR 250 ng/mL for 72 h,and the degree of Epo promoter methylation was detected by pyrosequencing.Protein expression levels of α-smooth muscle actin(α-SMA),platelet-derived growth factor receptor-β(PDGFRβ)and DNA methyltransferase(Dnmt3a)were detected by immunofluorescence and Western blot,and erythropoietin(EPO)levels in the supernatant were detected.Results Compared with the control group,5-Aza-CdR treatment significantly decreased the expression of Dnmt3a and hypermethylation of the Epo promoter,and subsequently decreased the expression of α-SMA and the expression ratio of α-SMA to PDGFRβ in myofibroblasts.Meanwhile,5-Aza-CdR treatment increased the level of EPO in the cell supernatant.Conclusions 5-Aza-CdR can reverse PMT by inhibiting Epo promoter hypermethylation in primary renal myofibroblasts.

Objective To examine the effect of the demethylating agent 5-aza-2'-deoxycytidine(5-Aza-CdR)on pericyte-myofibroblast transition(PMT)in primary rat renal myofibroblasts.Methods Rat primary renal myofibroblasts were treated with 5-Aza-CdR 250 ng/mL for 72 h,and the degree of Epo promoter methylation was detected by pyrosequencing.Protein expression levels of α-smooth muscle actin(α-SMA),platelet-derived growth factor receptor-β(PDGFRβ)and DNA methyltransferase(Dnmt3a)were detected by immunofluorescence and Western blot,and erythropoietin(EPO)levels in the supernatant were detected.Results Compared with the control group,5-Aza-CdR treatment significantly decreased the expression of Dnmt3a and hypermethylation of the Epo promoter,and subsequently decreased the expression of α-SMA and the expression ratio of α-SMA to PDGFRβ in myofibroblasts.Meanwhile,5-Aza-CdR treatment increased the level of EPO in the cell supernatant.Conclusions 5-Aza-CdR can reverse PMT by inhibiting Epo promoter hypermethylation in primary renal myofibroblasts.

Objective:To evaluate the effectiveness of anti-G straining maneuver (AGSM) in pilots by surface electromyography (sEMG), and to explore the relationships between characteristics of sEMG and anti-G endurance in pilots.Methods:Thirty-eight male high-performance fighter pilots who completed the human centrifuge test at the Air Force Medical Center were selected. Among them, 25 completed the 8.0 G for 10 s anti-G endurance test and 13 completed the 9.0 G for 10 s anti-G endurance test. The sEMG tester was used to keep track of the changes of sEMG in rectus abdominis, rectus femoris, anterior tibial and gastrocnemius muscles while pilots were engaged in AGSM. The anti-G endurance was evaluated according to the changes of visual fields and consciousness. The pilots were divided into 3 groups: the good vision and consciousness group, peripheral visual field narrowing group and endurance endpoint group. The differences in the integral electromyogram (iEMG), mean power frequency (MPF) and muscle input rates between the 3 groups were investigated.Results:A total of 25 pilots completed the 8.0 G for 10 s anti-G endurance test. Among them, 8 (32.0%) were in the good vision and consciousness group, 13 (52.0%) in the peripheral visual field narrowing group and 4 (16.0%) reached the endurance endpoint. Among the 13 pilots who completed the 9.0 G for 10 s anti-G endurance test, 3 (23.1%) were in the good vision and consciousness group, 6 (46.1%) in the peripheral visual field narrowing group, and 4 (30.8%) in the endurance endpoint group. The results of sEMG showed that the iEMG values of the anterior tibialis muscle in pilots under the 9.0 G for 10 s load were significantly different across endurance groups ( H=7.54, P=0.023), and that the iEMG values of the tibialis anterior muscle in the good vision and consciousness group were higher than those in the endurance endpoint group ( P=0.036). The negative slopes of MPF for the rectus abdominis, rectus femoris, anterior tibialis, and gastrocnemius muscles were higher in the good vision and consciousness group than in the other 2 groups, but the differences were not statistically significant ( P>0.05). During the 8.0 G for 10 s anti-G endurance test, there were significant differences in lower limb muscle contribution rates between the 3 groups ( F=4.19, P=0.029). The endurance endpoint group exhibited a lower contribution rate than the good vision and consciousness group ( P=0.025). During the 9.0 G for 10 s anti-G endurance test, there were significant differences in tibialis anterior muscle contribution rates between the 3 groups ( F=4.16, P=0.049). The endurance endpoint group demonstrated a lower contribution rate than the good vision and consciousness group ( P=0.049). Conclusions:The full and balanced activation of abdominal muscles and lower limb muscles, especially the effective mobilization of calf muscles, plays a pivotal role in improving pilots′ AGSM efficiency in high G environments.

Objective:To find out whether the performance of a China-made high performance human centrifuge can satisfy the need of high G training by conducting physiological experiments.Methods:The dynamic physical performance of the anti-G equipment with the human centrifuge was tested before 5 subjects underwent the gradual-onset rate (GOR) run and rapid onset rate (ROR) run experiments. The G onset rate of GOR was 0.1 G/s. The relaxed G-tolerance under GOR (GOR tolerance 1) and the anti-G straining maneuver aided G-tolerance under GOR (GOR tolerance 2) were tested respectively. The G onset rate of ROR was 3 G/s, and the closed-loop mode and pre-programed mode were employed respectively. The closed-loop mode involved 5 G 10 s and 8 G 10 s, where the subjects were required to manipulate the joystick to ensure that the real-time curve of the load matched the target curve. In the pre-programmed mode, the subjects were exposed to 8 G 10 s passively, without any operation requirements. A subjective evaluation form was filled out by subjects after the experiments, in which the 14 indexes for evaluation were about the gondola facilities and environment, running processes, medical monitoring and overall assessment.Results:Both the oxygen mask and anti-G suit achieved full pressurization within 2.0 s. The GOR tolerance 1 was [4.0(3.8, 4.6)] G while the GOR tolerance 2 was (6.2±0.5) G, suggesting a statistically significant difference ( Z=-2.63, P=0.008). The HP anti-G straining maneuver effect was (2.0±0.6) G. All the 5 subjects finished the 5 G 10 s experiment in a closed-loop mode. Three of them attempted 8 G 10 s in the closed-loop mode (1 subject achieved only 7.6 G peak acceleration, and the other 2 achieved full 8 G 10 s exposure), while the remaining 2 completed the 8 G 10 s in the pre-programmed mode. In the closed-loop mode, it was found that the stick force was too strong, the guiding G and real time G curve were not easy to distinguish for some of the subjects because the curve colors were similar, and that the subjects could not see the G curves clearly in case of a grayout. Both seat comfort and the voice quality of communication got the highest subjective assessment score [5.0(4.0, 5.0)] while the sensation of tumble got the lowest score (2.8±0.8). The median or mean scores of other subjective evaluation indexes ranged from 3.0 to 4.6 points. The overall score of subjective assessment was [4.0(3.5, 4.0)] points. Conclusions:The China-made high performance human centrifuge can meet the requirements of 8.0 G high G training, which can be made more effective and comfortable if the strong stick force and feeling of tumble during stop running are overcome.

Objective To construct an evaluation index system for the technical labor value of operators of large-scale medical equipment and conduct a practical measurement of it.Methods The literature survey method and semi-structured interview were used to preliminarily construct the evaluation index framework.The questionnaire survey method and expert consultation method were employed to screen and determine the final evaluation index system,and the entropy method was used to calculate the weight of each evaluation index.Based on the KANO model,the evaluation requirements of the technical labor value of MRI operators were investigated.Results The final expert authority coefficient of the consultation questionnaire was 0.80;the chi-square test results of Kendall's W coefficient were all statistically significant differences(P＜0.05);finally,5 first-level indicators,13 second-level indicators,and 22 third-level indicators were screened out,jointly forming the evaluation index system.The Cronbach's coefficients of the positive and negative questionnaires in the reliability analysis of the KANO model were 0.953 and 0.983 respectively;MRI operators perceived that the cerebral thinking load,the steps taken to operate the imaging equipment,and the difficulty in interpreting imaging results were more reflective of the value of their technical labor.Conclusion The evaluation index system of technical labor value of large medical equipment operators has been scientifically constructed to provide theoretical support for improving the performance evaluation system of large medical equipment operators.

Objective To identify the key influencing factors and role mechanisms of large-scale medical equip-ment allocation decision-making in public hospitals,and to provide a reference basis for optimizing resource alloca-tion strategies.Methods Through searching the literature related to large-scale medical equipment decision-making in public hospitals and combing the policies,the system of decision-making influencing factors was initially screened.The Delphi method and decision-making trial and evaluation laboratory method were used to obtain the key influencing factors of equipment allocation decision-making and to determine the interaction effects among the factors.Results A total of seven cause factors and nine effect factors were screened.Among them,cost-benefit analysis,equipment technical performance,and evaluation of similar equipment were the top three key drivers;leadership emphasis,equipment market price,and equipment supporting facilities were the top three key con-straints.Conclusion Priority be given to strengthening the management of driving factors,mainly by conducting a full-cycle assessment of cost-effectiveness,paying attention to the clinical value output of equipment technical performance,and monitoring regionally similar equipment.A dynamic response mechanism for constraints should be established,mainly to strengthen leadership decision-making,implement a centralized procurement price nego-tiation model and improve the pre-assessment system for ancillary facilities.