Background Retinal retinoic acid (RA) plays an important role in the formation of the lensinduced myopia.However,it is not clear how RA transfer the myopic signal to choroid throughout the retinal pigment epithelium (RPE) barrier.Objective The aim of this study was to investigate the effect of all-trans retinoic acid (atRA) on the barrier of RPE in lens-induced myopic eye of guinea pig.Methods Thirty left eyes of 30 21-dayold clean guinea pigs were randomized into normal control group and the model group.The models of out of focus were induced by covering of-6.00 D concave lens on the left eyes for 15 days.Radius of corneal curvature was measured using corneal curvimeter,and diopeter of the guinea pig was examined by mydriatic optometry.The length of ocular axis was detected by A-sonography.The animals were sacrificed and the retinas of the left eyes were isolated for the culture and passage of RPE cells.The third generation of cells were incubated Millcell-PET microporous film,and atRA at the concentration of 1 × 10-6,1 × 10-7,1 × 10-8 and 1 × 10-9 mol/L was added to the micropore respectively for 12 hours,and the micropores with equal-solvent served as negative control group.Methyl thiazolyl tetrazolium (MTT)colorimetric method was used to detect the survival rate of the cells.Subsequently,the transepithelial electrical resistance (TER) of the monolayer cells was determined with CN10-EVOM2 resistance measuring meter.The vesicular transport change of RPE membrane in different groups was evaluated by FM1-43 fluorescence staining.Results The mean diopter was (-2.20±0.95) D in the models,and that in the controls was (+ 1.15 ±0.30) D,with a significant difference between them (t =14.57,P＜ 0.01).The axial length was (8.24 ± 0.09) mm in the models and it was significantly longer than (7.81±0.05) mm in the controls (t=17.20,P＜0.01).RPE cells grew well to form a monolayer in Millcell culture pool after one week.After 24 hours of the atRA treatment,the survival rate of RPE cells reduced gradually with the increase of atRA concentration with the highest rate in the 1 × 10-9 mol/L atRA group (93.3 ％) and followed by the 1 × 10-8 mol/L atRA group (88.2％).More than half of the cells dead in the 1 × 10-6mol/L and 1 × 10-7mol/L atRA groups (53.8％ and 47.1％).Significant differences in the TER value and fluorescence staining intensity of the cells were seen among the various groups (F =43.89,P =0.00 ; F =26.13,P =0.00),with the maximal values in the 1 × 10-8mol/L atRA group.The FM1-43 fluorescence located on the cellular membrane and cytoplasm.Conclusions AtRA can increase the functional state of tight junction and vesicular transport,which regulated the RPE cell barrier in the guinea pig.

Objective:To construct the core indicators for entrustable professional activities in specialists in obstetrics and gynecology.Methods:A study group was formed by the specialists in obstetrics and gynecology and the experts in medical education. The core indicators for entrustable professional activities were constructed for the specialists in obstetrics and gynecology based on literature review and clinical practice, and then the Delphi method was used to conduct two rounds of expert letter consultation for screening and optimization from March 2021 to January 2023 to further identify the core indications.Results:The expert positive coefficient was 100% for the two rounds of consultation, with an expert authority coefficient of 0.82, and the Kendall's coefficient of concordance was 0.221 and 0.213, respectively (both P<0.01). Ten core indicators and their content descriptions were constructed for entrustable professional activities in obstetrics and gynecology specialists, and the experts had a degree of recognition of more than 80% for the importance of these ten entrustable professional activities, with a coefficient of variation of <0.25. This study determined the expected entrustable level of each indicator for specialists at the completion of the course, which ranged from grade 3 to 5; the highest level of 4.48 was observed for the diagnosis and treatment of outpatients, which was between the levels of mastery and expert; the lowest level of 3.52 was observed for laparoscopic hysterectomy, which was between the levels of competency and mastery. Conclusion:This study preliminarily constructs the core indicators for entrustable professional activities in specialists in obstetrics and gynecology, which provides a new exploration for the standardized training of specialists.