1.Study on Reducing Hepatotoxicity and Retaining Anti-osteoporosis Activity of Psoraleae Fructus Though Salt Processing Based on Zebrafish
Yiqi LIU ; Xuan WANG ; Qiqi FAN ; Zehua CHANG ; Shuo FAN ; Na WANG ; Zheng LI ; Xinfang XU ; Chongjun ZHAO ; Xiangri LI
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(9):79-90
ObjectiveTo investigate the mechanism of salt processing of Psoraleae Fructus (PF) through modern analytical techniques and biotechnology, focusing on its effects related to hepatotoxicity and anti-osteoporosis activity. MethodsThe zebrafish model was utilized to evaluate the impact of PF and salt-processed Psoraleae Fructus (SPF) on the hepatotoxicity (using 134.17 , 178.89, 268.34 mg·L-1 as low, medium, and high dose groups of PF, 135.04, 180.06, 270.08 mg·L-1 as low, medium, and high dose groups of SPF, respectively) and anti-osteoporotic activity (using 33.54 , 67.08 and 134.17 mg·L-1 as low, medium, and high dose groups of PF, 33.76, 67.52, 135.04 mg·L-1 as low, medium, and high dose groups of SPF, respectively), which was using alizarin red skull staining of zebrafish as an indicator of different batches of PF. The specific dosage of a batch of PF was taken as an example. Then ultra-performance liquid chromatography-quadrupole-time of flight-mass spectrometry(UPLC-Q-TOF-MS) analysis was employed to identify the chemical composition of PF before and after salt processing, and PCA, OPLS-DA, and independent sample t-test were used to elucidating the compositional changes associated with the effects of salt processing on hepatotoxicity and anti-osteoporosis activity. ResultsUnder specific conditions, PF induced notable hepatotoxicity in zebrafish while simultaneously demonstrating protective effect against prednisolone-induced osteoporosis. In comparison to PF, SPF showed alleviated hepatotoxicity while retaining significant anti-osteoporosis activity. UPLC-Q-TOF-MS analysis revealed that after salt processing, the overall chemical composition of PF showed a downward trend, with 69 components showing a decrease in content, represented by psoralen, and 13 components showing an increase, represented by 4′-O-methyl psoralen B. Further multivariate statistical analysis revealed 11 key differential components before and after salt processing of PF, including psoralen and bakuchiol. ConclusionSalt processing effectively diminishes hepatotoxicity without impairing therapeutic efficacy against osteoporosis of PF, which may be related to the compositional changes before and after salt processing of PF and provides key evidence to reveal the scientific significance of salt processing of PF.
2.Nanopackaged Astaxanthin Improves Demyelination in Multiple Sclerosis Model Mice by Scavenging Excessive Endogenous Formaldehyde
Wan-Jia LÜ ; Xin ZENG ; Zhi-Qian TONG ; Yang XING ; Xu YANG ; Mei-Na WU ; Ping MA
Progress in Biochemistry and Biophysics 2026;53(2):442-457
ObjectiveMultiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS); however, its underlying neurological pathogenic mechanisms remain incompletely understood. Endogenous formaldehyde (FA), a metabolic byproduct of methylation-demethylation cycles, has recently been implicated in neurotoxicity, oxidative damage, and cognitive impairment. This study aimed to investigate whether excessive FA contributes to myelin sheath demyelination in mice and to evaluate the protective effects and mechanisms of two FA-elimination strategies: sodium bisulfite (NaHSO3), a classical FA scavenger, and polyethylene glycol-modified astaxanthin nanoparticles (PEG-ATX@NPs), a brain-targeted nano-antioxidant formulation. MethodsA chronic demyelination model was established by feeding female C57BL/6J mice a diet containing 0.2% cuprizone (CPZ) for four weeks, followed by a two-week intervention period. Eighty mice were randomly assigned to four groups: NS (normal saline), CPZ+NS, CPZ+NaHSO3, and CPZ+PEG-ATX@NPs. Behavioral tests, including open-field, Y-maze, and pole-climbing assays, were conducted to assess locomotor activity, motor coordination, and working memory. FA levels in serum, corpus callosum, and spinal cord were measured using an Na-FA fluorescent probe and quantified via in vivo and ex vivo fluorescence imaging. Neuroinflammatory responses were evaluated by measuring TNF-α, IL-1β, and IL-6 levels using ELISA, while oxidative stress was assessed by reactive oxygen species (ROS) fluorescence intensity. Demyelination was examined via Luxol fast blue staining, and microglial activation was analyzed by Iba1 immunofluorescence. Correlation analyses were performed to explore relationships among FA levels, inflammatory cytokines, ROS intensity, and behavioral parameters. ResultsCompared with the NS group, mice in the CPZ+NS group exhibited significant weight loss, impaired motor coordination and memory, and markedly reduced myelin regeneration (P<0.05). FA levels and pro-inflammatory cytokines were significantly elevated in serum, corpus callosum, and spinal cord (P<0.05). FA-associated fluorescence in brain and spinal tissues, as well as ROS intensity across all tissues examined, also increased substantially (P<0.05). CPZ treatment induced pronounced microglial activation and severe demyelination in the corpus callosum (P<0.01). Both NaHSO3 and PEG-ATX@NPs effectively reduced FA accumulation in the brain and spinal cord, attenuated demyelination, suppressed microglial activation, decreased inflammatory cytokine levels, and improved motor and cognitive performance. These results confirm that CPZ induced severe demyelination accompanied by oxidative stress, neuroinflammation, and abnormal FA accumulation. Following intervention with either NaHSO3 or PEG-ATX@NPs, endogenous FA levels in the CNS were substantially reduced. Both treatments alleviated demyelination and significantly decreased the number of activated microglia. Levels of TNF-α, IL-1β, and IL-6 in serum, corpus callosum, and spinal cord were downregulated. Behavioral performance improved significantly, as evidenced by enhanced locomotor activity, better coordination, and improved memory function. These findings indicate that both FA-scavenging agents mitigate CPZ-induced biochemical and behavioral abnormalities. ConclusionThis study demonstrates that excessive endogenous FA is closely associated with cognitive impairment, inflammatory dysregulation, and demyelination in a CPZ-induced chronic demyelination mouse model. Clearing abnormally elevated FA effectively reduces neuroinflammation, suppresses microglial overactivation, decreases oxidative stress, and alleviates demyelination, ultimately improving motor and cognitive outcomes in mice. These results suggest that targeting endogenous FA represents a promising therapeutic strategy for MS and other demyelinating disorders. Further investigations are warranted to explore the long-term safety, dosage optimization, and molecular pathways involved in FA-mediated neurotoxicity.
3.Nanopackaged Astaxanthin Improves Demyelination in Multiple Sclerosis Model Mice by Scavenging Excessive Endogenous Formaldehyde
Wan-Jia LÜ ; Xin ZENG ; Zhi-Qian TONG ; Yang XING ; Xu YANG ; Mei-Na WU ; Ping MA
Progress in Biochemistry and Biophysics 2026;53(2):442-457
ObjectiveMultiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS); however, its underlying neurological pathogenic mechanisms remain incompletely understood. Endogenous formaldehyde (FA), a metabolic byproduct of methylation-demethylation cycles, has recently been implicated in neurotoxicity, oxidative damage, and cognitive impairment. This study aimed to investigate whether excessive FA contributes to myelin sheath demyelination in mice and to evaluate the protective effects and mechanisms of two FA-elimination strategies: sodium bisulfite (NaHSO3), a classical FA scavenger, and polyethylene glycol-modified astaxanthin nanoparticles (PEG-ATX@NPs), a brain-targeted nano-antioxidant formulation. MethodsA chronic demyelination model was established by feeding female C57BL/6J mice a diet containing 0.2% cuprizone (CPZ) for four weeks, followed by a two-week intervention period. Eighty mice were randomly assigned to four groups: NS (normal saline), CPZ+NS, CPZ+NaHSO3, and CPZ+PEG-ATX@NPs. Behavioral tests, including open-field, Y-maze, and pole-climbing assays, were conducted to assess locomotor activity, motor coordination, and working memory. FA levels in serum, corpus callosum, and spinal cord were measured using an Na-FA fluorescent probe and quantified via in vivo and ex vivo fluorescence imaging. Neuroinflammatory responses were evaluated by measuring TNF-α, IL-1β, and IL-6 levels using ELISA, while oxidative stress was assessed by reactive oxygen species (ROS) fluorescence intensity. Demyelination was examined via Luxol fast blue staining, and microglial activation was analyzed by Iba1 immunofluorescence. Correlation analyses were performed to explore relationships among FA levels, inflammatory cytokines, ROS intensity, and behavioral parameters. ResultsCompared with the NS group, mice in the CPZ+NS group exhibited significant weight loss, impaired motor coordination and memory, and markedly reduced myelin regeneration (P<0.05). FA levels and pro-inflammatory cytokines were significantly elevated in serum, corpus callosum, and spinal cord (P<0.05). FA-associated fluorescence in brain and spinal tissues, as well as ROS intensity across all tissues examined, also increased substantially (P<0.05). CPZ treatment induced pronounced microglial activation and severe demyelination in the corpus callosum (P<0.01). Both NaHSO3 and PEG-ATX@NPs effectively reduced FA accumulation in the brain and spinal cord, attenuated demyelination, suppressed microglial activation, decreased inflammatory cytokine levels, and improved motor and cognitive performance. These results confirm that CPZ induced severe demyelination accompanied by oxidative stress, neuroinflammation, and abnormal FA accumulation. Following intervention with either NaHSO3 or PEG-ATX@NPs, endogenous FA levels in the CNS were substantially reduced. Both treatments alleviated demyelination and significantly decreased the number of activated microglia. Levels of TNF-α, IL-1β, and IL-6 in serum, corpus callosum, and spinal cord were downregulated. Behavioral performance improved significantly, as evidenced by enhanced locomotor activity, better coordination, and improved memory function. These findings indicate that both FA-scavenging agents mitigate CPZ-induced biochemical and behavioral abnormalities. ConclusionThis study demonstrates that excessive endogenous FA is closely associated with cognitive impairment, inflammatory dysregulation, and demyelination in a CPZ-induced chronic demyelination mouse model. Clearing abnormally elevated FA effectively reduces neuroinflammation, suppresses microglial overactivation, decreases oxidative stress, and alleviates demyelination, ultimately improving motor and cognitive outcomes in mice. These results suggest that targeting endogenous FA represents a promising therapeutic strategy for MS and other demyelinating disorders. Further investigations are warranted to explore the long-term safety, dosage optimization, and molecular pathways involved in FA-mediated neurotoxicity.
4.Association between snack consumption and depressive symptoms among first year junior high school students with different left behind experiences in Yunnan Province
LIU Na, WU Huijuan, WANG Liangui, LUO Chengyong, CAO Yanrong, FU Yun, ZHANG Tai,〖JZ〗 KONG Jing, HU Mengdie, XIONG Yuan, XU Honglü ;
Chinese Journal of School Health 2026;47(1):18-22
Objective:
To explore the relationship between snack consumption and depressive symptoms in first year junior high school students with different left behind experiences in Yunnan Province, so as to provide a basis for improving depressive symptoms among first year junior high school students with different left behind experiences.
Methods:
From October to December 2022,a cluster random sampling method was used to select 8 500 first year junior high school students from 11 ethnic minority areas (Fugong County, Longling County, Longyang District, Luchun County, Mojiang County, Nanjian County, Qiaojia County, Shuangjiang County, Tengchong City, Yuanmou County, Zhenyuan County) in Yunnan Province for a questionnaire survey. The Chinese version of Depression Anxiety Stress Scale-21 was applied to assess depressive symptoms in first year junior high school students, and snack consumption was collected by employing food frequency questionnaire. The generalized linear model was used to analyze the association between first year junior high school students snack consumption and depressive symptoms, and the analysis was stratified according to left behind experience.
Results:
The detection rates of depressive symptoms among firstyear junior high school students with and without left behind experience were 36.25% and 26.91%, respectively. After controlling for confounding variables, the generalized linear model analysis showed that sweet snacks ( β=0.16, 95%CI =0.07-0.25), fast food ( β=0.14, 95%CI =0.04-0.23) and carbonated drinks ( β=0.09, 95%CI =0.01-0.17) of first year junior high school students with left behind experience (all P <0.05). Compared with those without such behavior, the risk of depressive symptoms was higher in consumption of fast food ( β=0.13, 95%CI =0.07-0.18) and carbonated drinks ( β=0.10, 95%CI =0.06-0.15)among first year junior high school students without left behind experience (both P <0.05).
Conclusion
Snack consumption among first year junior high school students in Yunnan may increase the risk of developing depressive symptoms, while first year junior high school students with left behind experience may have a greater risk of developing depressive symptoms.
5.Establishment and Evaluation of New Mouse Model of Rheumatoid Arthritis Combined with Interstitial Lung Disease
Liting XU ; Qingyu ZHAO ; Chao YANG ; Lianhua HE ; Congcong SUN ; Shuangrong GAO ; Lili WANG ; Chunfang LIU ; Na LIN
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(6):81-90
ObjectiveTo establish a mouse model of rheumatoid arthritis with interstitial lung disease (RA-ILD) in DBA/1 mice using Porphyromonas gingivalis (Pg) infection combined with collagen-induced arthritis (CIA), and to comprehensively evaluate pathological characteristics in joints, lungs, and serum. MethodsForty DBA/1 mice were randomly divided into four groups, i.e., Control, Pg infection (Pg), CIA, and Pg infection combined with CIA (Pg+CIA), with 10 mice in each group. Arthritis clinical symptoms were evaluated by recording arthritis incidence and clinical scores. Micro-CT scanning was used to assess knee joint pathology. Histopathological changes and collagen deposition in knee joints and lung tissues were analyzed using hematoxylin-eosin (HE) and Masson staining. Immunohistochemistry was performed to detect protein expression of α-smooth muscle actin (α-SMA), typeⅠ collagen (ColⅠ), and fibronectin (FN) in lung tissues. Real-time quantitative polymerase chain reaction(Real-time PCR)was used to measure mRNA expression levels of α-SMA, ColⅠ, FN, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β in lung tissues. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum levels of Pg, cyclic citrullinated peptide (CCP), and immunoglobulin G (IgG). ResultsJoint lesions: The CIA and Pg+CIA groups showed 100% arthritis incidence, with evident joint redness, swelling, and deformity. The number of affected limbs was 27 and 28, and clinical scores were 68 and 70, respectively. No obvious clinical symptoms were observed in the Pg group. Histopathological and imaging analyses showed severe joint lesions in the CIA and Pg+CIA groups, with significantly increased histopathological scores, bone mineral density, bone volume fraction, trabecular thickness, and trabecular number compared to the Control group (P<0.01). No obvious joint pathology was observed in the Pg group. Lung lesions: The Pg+CIA group exhibited marked alveolar inflammation, interstitial inflammatory cell infiltration, and alveolar wall thickening, with pronounced blue staining of collagen fibers. Histopathological scores and collagen area ratios were significantly higher than those of the Control, Pg, and CIA groups (P<0.05). Lung protein and mRNA expression levels of α-SMA, ColⅠ, and FN were markedly increased, and mRNA levels of IL-6, TNF-α, and IL-1β were significantly elevated compared to the Control group (P<0.05). Serology: The Pg+CIA group showed significantly higher levels of CCP, Pg, and IgG compared with the Control, Pg, and CIA groups (P<0.05). ConclusionDBA/1 mice subjected to Pg infection combined with CIA exhibited pronounced symptoms and pathological features of RA-ILD, along with elevated serum anti-CCP antibody levels. This model represents a novel RA-ILD mouse model, providing a valuable experimental tool for investigating RA-ILD pathogenesis and developing new therapeutics, and serves as a basis for establishing anti-cyclic citrullinated peptide antibody (ACPA)-positive RA-ILD animal models.
6.Guidelines for establishing animal models of rheumatoid arthritis with cold dampness obstruction pattern and damp heat obstruction pattern (2024 Version)
Na LIN ; Yanqiong ZHANG ; Changhong XIAO ; Shenghao TU ; Jianning SUN ; Shijun XU ; Xia MAO
Science of Traditional Chinese Medicine 2026;4(2):174-180
Rheumatoid arthritis belongs to arthralgia in the theory of traditional Chinese medicine, with cold dampness obstruction pattern (CDO) and damp heat obstruction pattern (DHO) as the main pattern types. Fine therapeutic effects have been obtained in clinical practice following the differentiation of CDO and DHO. However, suitable animal models are not available currently. For adapting to the clinical diagnosis, as well as carrying out basic research of integrated Chinese and Western medicine and preclinical study on new Chinese medicine in a better way, the “Guidelines for Establishing Animal Models of Rheumatoid Arthritis with Cold Dampness Obstruction Pattern and Damp Heat Obstruction Pattern” (referred to as “Guidelines”) were compiled by our research group in cooperation with renowned experts in clinical, pharmaceutical, zoological, and methodological research fields. According to the theory of disease and syndrome integration, experts standardized the establishment methods for animal models of rheumatoid arthritis with CDO and DHO. The Guidelines were compiled via the nominal group method according to the principle of evidence coming in main place, consensus as the auxiliary, and experience as the references. Contents such as animal species, arthritis induction methods, external stimulation conditions, and assessment indicators were specified in the Guidelines based on the comprehensive evaluation of pathogenesis homology, behavioral phenotypic consistency, and drug therapy predictability between animal models and human diseases. The Guidelines will be applicable to the research on syndromes in rheumatoid arthritis, elucidation of acting mechanism, and development of new medicine, and provide reference for standardizing other types of animal models with the integration of disease and syndrome, to promote the modernization of Chinese medicine research.
7.Preclinical mouse models for studying cholangiocarcinoma
Shanru Yang ; Chaodi Bao ; Yuan Li ; Yangxiang Ou ; Yifan Jiang ; Wenjie Xu ; Dongfang Zheng ; Na Li ; Mengjie Yang ; Fuyan Wang ; Xin Hou
Liver Research 2026;10(1):22-34
Cholangiocarcinoma (CCA) is a malignancy characterized by tumor cells originating in the liver or bile ducts, exhibiting features of cholangiocyte differentiation. It poses a significant clinical challenge due to the limited diagnostic and therapeutic options available. Robust animal models are essential for advancing our understanding of CCA pathogenesis and developing effective treatments. This review provides a comprehensive overview of CCA mouse models, highlighting various approaches, including chemical induction, genetically engineered models, and tumor xenografts. Each model is discussed in terms of its establishment techniques, pathological characteristics, and research significance, with a focus on intrahepatic CCA. Chemical induction models, such as diethylnitrosamine- and azoxymethane-induced models, offer insights into tumorigenesis processes, whereas genetically modified models involving alterations in key genes such as Kirsten rat sarcoma viral oncogene homolog, tumor protein 53, and isocitrate dehydrogenase serve as important tools for studying the molecular mechanisms underlying CCA. Xenograft models, including patient-derived xenografts, bridge the gap between experimental research and clinical applications, allowing for precise therapeutic evaluations. By comparing these models, this review underscores their respective advantages and limitations, paving the way for future studies aiming to optimize and innovate CCA modeling strategies.
8.Characteristics of newly diagnosed occupational diseases in Huangpu District, Guangzhou City, 2010-2024
Na SHI ; Yu HUANG ; Xianbang CAO ; Dan XU
China Occupational Medicine 2026;53(2):212-215
Objective To analyze the epidemiological characteristics of newly reported occupational diseases in Huangpu District, Guangzhou City, from 2010 to 2024. Methods Data on newly reported occupational diseases in Huangpu District, Guangzhou City, from 2010 to 2024 were collected from the Occupational Diseases and Health Hazard Factors Monitoring Information System, a subsystem of the China Disease Prevention and Control Information System. The spectrum composition and distribution characteristics of diseases were analyzed by year, enterprise and industry. Results A total of 501 newly diagnosed occupational disease cases involving seven categories and 21 specific disease types were reported in Huangpu District from 2010 to 2024. The overall trend showed a pattern of rapid increase, decline after peaking, and low-level fluctuation. The top four occupational disease categories by case count were occupational pneumoconiosis and other respiratory diseases (32.53%), occupational ear, nose, and throat diseases (30.14%), occupational diseases caused by physical factors (21.96%), and occupational chemical poisoning (12.18%). The predominant specific diseases type within these four categories were occupational pneumoconiosis, occupational noise-induced deafness, occupational hand-arm vibration disease, and occupational benzene poisoning. Cases were mainly distributed in enterprises invested by Hong Kong-, Macao-, and Taiwan, in private enterprises, and in foreign-invested enterprises, accounting for 82.44% of all cases. Medium- and small-sized enterprises were predominant in terms of enterprise scale, accounting for 46.71% and 34.33%, respectively. Cases were predominantly distributed across four industries: manufacturing of railway, ship, aerospace, and other transport equipment; manufacture of articles for culture, education, arts and crafts, sport, and entertainment; manufacturing of general-purpose machinery; and manufacture of chemicals and chemical products. Collectively, these sectors accounted for 56.09% of all cases. Conclusion Future occupational health work in Huangpu District should focus on key diseases including occupational pneumoconiosis, occupational noise-induced deafness, and occupational benzene poisoning. Prevention and control measures should target small- and medium-sized enterprises in high-risk industries such as shipbuilding and automobile manufacturing.
9.A time-stratified case-crossover study on effects of heatwaves on daily outpatient visits for skin diseases in Urumqi from 2016 to 2024
Ying ZHANG ; Zhe LIU ; Chunyu XU ; Na LI ; Jingyi LIU ; Haofeng YANG ; Li DING ; Jingxiu HAN
Journal of Environmental and Occupational Medicine 2026;43(8):967-971
Background Against the background of global warming, frequent heatwaves pose a major threat to public health. Objective To investigate the effects of heatwaves on outpatient visits for skin diseases in Urumqi, characterize the exposure–response relationship, identify the critical temperature threshold, and provide scientific evidence for targeted prevention and control of heat-related skin diseases. Methods Data on meteorological conditions, air quality, and dermatological outpatient visits from 10 hospitals in Urumqi were collected from January 1, 2016 to December 31, 2024. A time-stratified case-crossover design combined with a distributed lag model was adopted to construct a conditional logistic regression model, with adjustment for potential confounders, including relative humidity, air pollutants, and COVID-19 lockdown measures. With a maximum lag of 14 d, single-lag and cumulative-lag effects of heatwaves were examined, and the exposure–response relationship between temperature and the risk of dermatological outpatient visit was fitted. Results A total of 385 heatwave days were identified in Urumqi from January 1, 2016 to December 31, 2024. These days were concentrated between June and September and showed an increasing annual trend. The median daily number of dermatological outpatient visits during heatwave periods (165 cases) was significantly higher than that during control periods (114 cases) (Z=−5.108, P<0.001). After adjusting for confounders, the odds of dermatological outpatient visits during heatwaves were 1.088 times higher than those of the control period (OR=1.088, 95%CI: 1.069, 1.107). Single-lag effects were statistically significant from lag0 to lag11 (P<0.05), peaking at lag0 (OR=1.088, 95%CI: 1.069, 1.107), showing an acute and immediate effect. Cumulative-lag effects were statistically significant from 1 to 14 d (P<0.05), peaking at lag04 (OR=1.117, 95%CI: 1.099, 1.136). The exposure–response relationship indicated that the OR values increased steeply with increasing temperature when the daily mean temperature exceeded 24.2 ℃, peaking at approximately 28.1 ℃ (OR=1.400, 95%CI: 1.189, 1.649). Conclusions Heatwave exposure is significantly associated with an increased risk of dermatological outpatient visits among residents in Urumqi. The impact of high temperature on skin diseases is predominantly acute, with peak risks observed on the day of exposure and within the subsequent 4 d. A daily mean temperature of 24.2 ℃ can serve as the critical threshold for heightened dermatological consultation risk. Strengthened health education and early warning systems are recommended to mitigate heatwave-related adverse dermatological outcomes.
10.Cytotoxicity Studies of Light-oxygen-voltage (LOV) Domain Photosensitizers
Shuang XU ; Ben WAN ; Na SHA ; Kai-Hong ZHAO
Progress in Biochemistry and Biophysics 2025;52(2):487-500
ObjectiveAt present, the most commonly used photosensitizers in photodynamic therapy are still chemical photosensitizers, such as porphyrin and methylene blue, in order to specifically target cellular tissues, and thus poison cells, chemical photosensitizers need to use antibody conjugation or a transgenically encoded tag with affinity for the modified photosensitizing ligand, e.g. FlAsH, ReAsh or Halo Tag. Gene-encoded photosensitizers can directly poison cells by targeting specific cell compartments or organelles. However, currently developed gene-encoded photosensitizers have low reactive oxygen species production and low cytotoxicity, so it is necessary to continue to develop and obtain photosensitizers with higher reactive oxygen species production for the treatment of microbial infections and tumors. MethodsIn this study, we developed a photosensitizer LovPSO2 based on the light-oxygen-voltage (LOV) structural domain of phototropin-1B-like from Oryza sativa japonica. LovPSO2 was expressed in E. coli BL21(DE3) and purified to obtain protein samples, the purified protein samples were added 3 µmol/L singlet oxygen probe of SOSG and 5 µmol/L superoxide anion probe of DHE after fixed to A445=0.063±0.003, respectively, then measured every 2 min of singlet oxygen production for 10 min and every 1 min of superoxide anion production for 5 min under blue light irradiation at 445 nm, 70 µmol·m-2·s-1. ResultsThe results showed that LovPSO2 could produce a large amount of singlet oxygen under blue light irradiation at 445 nm, 70 µmol·m-2·s-1, and its singlet oxygen quantum yield was 0.61, but its superoxide anion yield was low, so in order to improve the superoxide anion yield of LovPSO2, a mutant with a relatively high superoxide anion yield was obtained by further development and design on its basis LovPRO2. The stability of proteins is crucial for research in drug development and drug delivery, among others. Temperature and light are the key factors affecting the production of reactive oxygen species (ROS) by photosensitive proteins and their stability, while the temperature in cell culture and mammals in vivo is about 37°C, and the temperature inside tumor cells is about 42-45°C. Therefore, we further analyzed the photostability of miniSOG, SOPP3, LovPSO2, and LovPRO2 and their thermostability at 37℃ and 45℃. The analysis of proteins thermostability showed that LovPSO2 and LovPRO2 had better thermostability at 37℃ and 45℃, respectively. Analysis of the photostability of the proteins showed that LovPRO2 had better photostability. In addition, to further determine the phototoxic effects of photosensitizers, LovPSO2 and LovPRO2 were expressed in E. coli BL21(DE3) and HeLa cells, respectively. The results showed that LovPSO2 and LovPRO2 had better phototoxicity to E. coli BL21(DE3) under blue light irradiation, and the cellular phototoxicity lethality was as high as 90% after 30 min of continuous light irradiation, but the phototoxicity was weaker in HeLa cells. The reason for this result may be that the intracellular environment exacerbated the photobleaching of FMN encapsulated by LovPSO2 and LovPRO2, respectively, which attenuated the damage of reactive oxygen species to animal cellular tissues, limiting its use as a mechanistic tool to study oxidative stress. ConclusionLovPSO2 and LovPRO2 can be used as antibacterial photosensitizers, which have broader application prospects in the food and medical fields.


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