Photohardening therapy, also known as photodesensitization therapy, refers to the phototherapy and photochemotherapy of idiopathic actinic dermatoses, and its goal is to improve the patients′ tolerance to sunlight and prevent disease flares. Its mechanisms of action involve a variety of cellular and inflammatory factors. This therapy is suitable for all idiopathic actinic dermatoses, with definite efficacy and good safety. However, the treatment specificity usually leads to poor compliance. The development of UVA1 rush hardening and home phototherapy is expected to solve this problem.

Objective:To investigate serum lipidomic profiles in patients with chronic actinic dermatitis (CAD), and to search for biomarkers of CAD.Methods:A retrospective analysis was conducted. Serum samples were collected from 46 patients with CAD and 16 age- and gender-matched healthy controls in the Guangzhou Institute of Dermatology from April 2011 to December 2021. Changes in serum lipid composition and expression were assessed by liquid chromatography-mass spectrometry. Principal component analysis, partial least squares discriminant analysis, and orthogonal partial least squares discriminant analysis were performed to screen differential biomarkers, and receiver operating characteristic (ROC) curve analysis was conducted to screen diagnostic markers. Comparisons of the age and gender distribution between groups were performed using t test and chi-square test, respectively. Results:The 46 CAD patients were aged from 30 to 84 (60.39 ± 10.52) years, including 41 males and 5 females; the 16 healthy controls were aged from 50 to 89 (59.81 ± 10.72) years, including 14 males and 2 females; there were no significant differences in the age or gender distribution between the two groups (age: t = 0.19, P = 0.853; gender: χ2 = 0.03, P = 0.859). Totally, 4 136 lipid molecules belonging to 40 subclasses were identified in the serum samples from CAD patients as well as healthy controls. Twenty-two differential lipid molecules were identified between the CAD patients and healthy controls, belonging to 9 subclasses (triglycerides, sphingomyelin, phosphatidylserine, phosphatidylethanolamine, monofatty acid glycerides, lysophosphatidylcholine, hexose ceramide, diglycerides, and cardiolipin). When the combinations of triglycerides (37.7e) and Na, those of monoglycerides (22.3) and NH 4, or those of phosphatidylserine (18.0_18.1) and H served as diagnostic markers separately, the areas under the ROC curve (AUCs) were all > 0.8, and the AUCs of 16 differential lipid molecules were all > 0.7. Conclusion:The serum lipid composition differed between healthy controls and CAD patients, and the combinations of triglycerides (37.7e) and Na, those of monoglycerides (22.3) and NH 4, and those of phosphatidylserine (18.0_18.1) and H may be promising biomarkers for the diagnosis of CAD.

Objective:To evaluate the effect of metformin on ultraviolet A (UVA) -induced photoaging of an immortalized human keratinocytes cell line (HaCaT), and to explore its potential mechanisms.Methods:Cell counting kit 8 (CCK8) assay was performed to evaluate the effect of metformin at different concentrations (0 - 100 mmol/L) on the viability of HaCaT cells, and 10 mmol/L metformin was selected for subsequent experiments. Cultured HaCaT cells were divided into a blank control group (conventional culture), a metformin group (treated with culture medium containing 10 mmol/L metformin), a UVA irradiation group (conventional culture for 24 hours followed by 10 J/cm 2 UVA irradiation) and a metformin + UVA group (treated with culture medium containing 10 mmol/L metformin for 24 hours followed by 10 J/cm 2 UVA irradiation) ; UVA irradiation was performed at a dose of 10 J/cm 2 once a day for 3 consecutive days. After 4-day treatment, cells were collected, the β-galactosidase assay was performed to determine the proportion of senescent cells in each group, 2′, 7′-dichlorodihydrofluorescein diacetate assay to detect levels of intracellular reactive oxygen species (ROS), and the comet assay to detect DNA damage levels. Additionally, some HaCaT cells were divided into the blank control group, metformin group, 1.25 μmol/L dorsomorphin (an adenosine monophosphate-activated protein kinase [AMPK] inhibitor) + metformin group, and 2.5 μmol/L dorsomorphin + metformin group, and cells in the latter two groups were treated with 1.25 and 2.5 μmol/L dorsomorphin respectively for 2 hours, followed by the treatment with 10 mmol/L metformin for 24 hours. Western blot analysis was performed to determine the cellular localization and phosphorylation levels of nuclear factor-erythroid 2-related factor 2 (Nrf2). By using the small-interfering RNA (siRNA) -mediated silencing method, siRNA-Nrf2 was transfected into HaCaT cells to knock down Nrf2 expression (siRNA-Nrf2 group) ; 2.5 μmol/L dorsomorphin-treated HaCaT cells or Nrf2-knockdown HaCaT cells were treated with metformin and UVA irradiation (dorsomorphin + metformin + UVA group, siRNA-Nrf2 + metformin + UVA group, respectively), and the proportions of senescent cells were further calculated in each group. Statistical analysis was carried out by using one-way analysis of variance and two-way analysis of variance, and least significant difference (LSD) - t test was used for multiple comparisons. Results:Treatment with different concentrations of metformin for 24 hours could affect the viability of HaCaT cells to varying degrees ( F = 5 206.31, P < 0.001) ; there were no significant differences in the relative survival rates of HaCaT cells between the 10 - 20 mmol/L metformin groups and the control group (0 mmol/L metformin group, all P > 0.05), while the relative cell survival rates were significantly lower in the 25 - 100 mmol/L metformin groups than in the control group (all P < 0.05). After UVA irradiation, HaCaT cells shrank significantly and became narrow and elongated, and the intercellular spaces increased; the relative cell survival rate was significantly lower in the UVA irradiation group (76.13% ± 1.03%) than in the blank control group (100.00% ± 1.24%, LSD- t = 14.86, P < 0.001), but significantly higher in the metformin + UVA group (106.69% ± 2.45%) than in the UVA irradiation group (LSD- t = 11.55, P < 0.001). Moreover, the UVA irradiation group showed significantly increased proportions of senescent cells (45.14% ± 4.98%), intracellular ROS levels (144.61% ± 4.91%), and percentages of DNA in the tail (75.33% ± 1.77%) compared with the blank control group (23.84% ± 1.89%, 55.49% ± 1.57%, 1.88% ± 0.29%, respectively, all P < 0.001), while the metformin + UVA group showed significantly decreased proportions of senescent cells (24.26% ± 1.34%), intracellular ROS levels (58.62% ± 2.17%), percentages of DNA in the tail (15.83% ± 1.23%) compared with the UVA irradiation group (all P < 0.001). Western blot analysis showed that the Nrf2 expression in the cytoplasm was lower in the 10 mmol/L metformin group than in the blank control group, while the phosphorylated Nrf2 expression in the nuclei was higher in the 10 mmol/L metformin group than in the blank control group, suggesting that metformin could effectively induce the phosphorylation of Nrf2 and its nuclear translocation; both the pretreatment with 1.25 and 2.5 μmol/L dorsomorphin could significantly reduce the phosphorylation levels of AMPKα and Nrf2 induced by 10 mmol/L metformin. The proportions of senescent cells in the dorsomorphin + metformin + UVA group and the siRNA-Nrf2 + metformin + UVA group were 67.84% ± 2.74% and 65.94% ± 1.33%, respectively, which were significantly higher than those in the metformin + UVA group (37.76% ± 1.64%, t = 14.45, 13.34, respectively, both P < 0.001) . Conclusion:Metformin may inhibit UVA-induced photoaging of HaCaT cells by activating the AMPK/Nrf2 signaling pathway, scavenging ROS and reducing DNA damage.

Objective To investigate the efficacy of entecavir (ETV) versus tenofovir disoproxil fumarate (TDF) and the treatment measures for poor response in previously untreated chronic hepatitis B (CHB) patients with high viral load. Methods A total of 165 CHB patients who received antiviral therapy and met the inclusion criteria in Department of Infectious Diseases, The First Affiliated Hospital of Guangxi Medical University, from June 2016 to July 2021 were enrolled. The patients enrolled had a baseline HBV DNA level of > 6lg copies/ml and were previously untreated CHB patients who had used ETV or TDF for 48 weeks, and quantitative real-time PCR was used to measure HBV DNA. Virologic response rate was calculated after 48 weeks of treatment; a logistic regression analysis was used to investigate the influencing factors for the response of HBV DNA < 500 copies/mL and HBV DNA < 100 copies /mL at 48 weeks; a stratified analysis was performed to compare the virologic response rate of HBV DNA < 500 copies /ml and HBV DNA < 100 copies/ml after 48 weeks between the patients with different ages, sexes, baseline HBV DNA levels, baseline alanine aminotransferase (ALT) levels, types of first-line medication, and HBeAg statuses. The Mann-Whitney U test was used for comparison of non-normally distributed continuous data between two groups, the chi-square test or the Fisher's exact test was used for comparison of categorical data between two groups, and the binary logistic regression model was used for multivariate analysis. Results After 48 weeks of treatment, 85.5% (141/165) of the patients achieved an HBV DNA load of < 500 copies/mL, and 66.1% (109/165) of the patients achieved an HBV DNA load of < 100 copies /mL, with no significant difference in treatment outcome between the ETV group and the TDF group. The multivariate logistic regression analysis showed that sex( OR =2.793, 95% CI : 1.197-6.517), baseline HBV DNA( OR =0.369, 95% CI : 0.142-0.959), baseline ALT( OR =4.556, 95% CI : 1.770-11.732), and baseline HBeAg( OR =0.120, 95% CI : 0.033-0.429) were influencing factors for complete virologic response(all P < 0.05). For the patients with normal ALT (≤40 U/L) at baseline, 75.6% (34/45) achieved an HBV DNA load of < 500 copies/mL after 48 weeks of treatment, and 53.3% (24/45) achieved an HBV DNA load of < 100 copies/mL, with no significant difference in treatment outcome between the ETV group and the TDF group. For the patients with abnormal ALT (> 40 U/L) at baseline, 89.2% (107/120) achieved an HBV DNA load of < 500 copies/mL after 48 weeks of treatment, and the proportion of such patients in the TDF group was significantly higher than that in the ETV group (96.1% vs 84.1%, χ 2 =4.386, P =0.036); 70.8% (85/120) achieved an HBV DNA load of < 100 copies/mL, the proportion of such patients was no significant difference between the TDF group and the ETV group (78.4% vs 65.2%). The response of HBV DNA < 100 copies/ml of the normal baseline ALT group and the abnormal baseline ALT group, there were no significant differences between the patients aged≤30 years and aged > 30 years (77.8% vs 47.2%, 85.2% vs 66.7%). For the patients who did not achieve complete virologic response (HBV DNA ≥100 copies/mL) after 48 weeks of treatment, 87.9% (29/33) achieved complete virologic response after the original treatment regimen was prolonged for 48 weeks, and 100% (9/9) of the patients achieved complete virologic response after switching to or adding the first-line nucleos(t)ide analogues (NUCs) without cross-resistance sites with the original regimen for another 48 weeks. Conclusion The patients aged > 30 years should receive antiviral therapy as early as possible, regardless of viral load and ALT level, especially those with a family history of liver cirrhosis or hepatocellular carcinoma; the patients aged ≤30 years who have a normal ALT level and a high viral load should consider initiating antiviral therapy after providing informed consent. For the patients with poor response after 48 weeks of treatment, first-line NUCs without cross-resistance sites with the original regimen should be switched to or added in time.

Objective:To explore the efficacy and safety of unrelated mismatched hematopoietic stem cell transplantation(HSCT)for thalassemia major.Methods:For this retrospective cohort study, 15 patients with β-thalassemia major underwent unrelated mismatched HSCT between January 2018 and April 2022. There were 8 males and 7 females with a median age of 7(3-12)years and a median ferritin level of 3 417.3(223-14 485)μg/L. The conditioning regimens on the basis of fludarabine(Flu), busulfan(Bu)and cyclophosphamide(CTX)and GVHD prophylaxis on the basis of cyclosporine(CsA), mycophenolate mofetil(MMF), anti-human thymocyte immunoglobulin(ATG)plus low-dose post-cyclophosphamide(PTCy)and mesenchymal stem cells were offered.Results:Up until April 1, 2022, 15 children were successfully implanted during a median follow-up period of 24.1(11-49)months and all of them achieved stable donor chimerism. The median time to neutrophil and platelet engraftment were 12(11-22)and 14(8-38)days respectively. Except for 2 deaths, 13 cases survived. The estimated 2-year probability of overall survival(OS)and thalassemia-free survival(TFS)were both 86.67%. There were 5 cases of acute graft versus host disease (aGVHD) below grade Ⅱ, 2 cases of grade Ⅲ to Ⅳ aGVHD, and 3 cases of localized chronic graft versus host disease (cGVHD) after transplantation. No gengralized cGVHD occurred. Both cytomegalovirus and Epstein-Barr virus were activated in five recipients.Conclusions:Unrelated mismatched donor HSCT is both safe and feasible for thalassemia major.

Objective:To investigate the effect of pterostilbene on the growth, apoptosis and autophagy of a human papillomavirus type 16 (HPV-16) -immortalized cervical epithelial cell line H8.Methods:H8 cells were treated with pterostilbene at different concentrations of 0 (control group) , 25, 50, 75, 100 μmol/L for 24 and 48 hours. Cell counting kit-8 (CCK8) assay was performed to evaluate the cellular proliferative activity, flow cytometry was conducted to detect apoptosis and cell cycle, monodansylcadaverine (MDC) staining and fluorescence microscopy were performed to detect autophagy, and Western blot analysis was conducted to determine the expression of the cell cycle-related protein cyclinD1, apoptosis-related proteins caspase-3 and caspase-9, autophagy-related proteins Beclin1, microtubule-associated protein 1 light chain 3 (LC3) -Ⅱ/Ⅰ, ATG5 and P62, as well as HPV oncoproteins E6 and E7. Statistical analysis was carried out by using one-way analysis of variance, repeated measures analysis of variance and least significant difference- t test. Results:After 48-hour treatment with pterostilbene at different concentrations of 0, 25, 50, 75, 100 μmol/L, the relative cellular proliferation rate significantly differed among the groups (100.00% ± 1.56%, 99.02% ± 4.97%, 93.59% ± 2.01%, 81.28% ± 4.90%, 69.17% ± 7.56%, respectively; F = 77.22, P < 0.05) , and gradually decreased along with the increase in the concentration of pterostilbene; compared with the control group, the pterostilbene groups all showed significantly decreased cellular proliferation rate (all P < 0.05) . After 24-hour treatment with pterostilbene, the proportions of H8 cells at G1, G2 and S phases significantly differed among the above groups ( F = 7 845.00, 51.14, 266.50, respectively, all P < 0.05) ; compared with the control group, the pterostilbene groups showed significantly increased proportions of H8 cells at G1 and G2 phases (all P < 0.05) , but significantly decreased proportions of H8 cells at S phase ( P < 0.05) . After 48-hour treatment with pterostilbene, the apoptosis rate was significantly higher in the 25-, 50-, 75- and 100-μmol/L pterostilbene groups (14.66% ± 0.22%, 13.50% ± 0.49%, 14.56% ± 0.19%, 15.30% ± 0.76%, respectively) than in the control group (11.58% ± 0.50%, all P < 0.05) . After 24-hour treatment with pterostilbene, MDC staining showed only a small number of H8 cells with bright dot-like fluorescence in the control group, but increased number of autophagosome-positive H8 cells with bright dot-like fluorescence in the pterostilbene groups. Western blot analysis revealed that there were significant differences in the protein expression of cyclin D1, caspase-3, caspase-9, Beclin1, LC3-Ⅱ/Ⅰ, ATG5, P62, E6 and E7 among the control and pterostilbene groups after 24- and 48-hour treatment with pterostilbene (all P < 0.05) . The treatment with pterostilbene could down-regulate the expression of cyclin D1, E6 and E7, and up-regulate the expression of caspase-3, caspase-9, Beclin1, LC3-Ⅱ/Ⅰ, ATG5 and P62, with significant differences between the control group and most pterostilbene groups in expression of the above proteins (all P < 0.05) . Conclusion:Pterostilbene can inhibit the proliferation of H8 cells, promote their apoptosis and autophagy, and down-regulate the expression of oncogenes E6 and E7.

Objective: To investigate the expression of myocyte enhancer factor 2B (MEF2B) in mantle cell lymphomas (MCL), and to analyze the correlation between the expression of MEF2B and pathological subtypes, structural subtypes, SOX11 expression and its clinical significance. Methods: Paraffin-embedded tissues were stained with HE, immunohistochemistry (EnVision method) and fluorescence in situ hybridization (FISH) , in addition, the clinical and pathological data of 60 cases of MCL were collected at Sun Yat-sen University Foshan Hospital and Sun Yat-sen University Cancer Center from January,2002 to May, 2019 for analysis. Results: Of the 60 MCLs, males is predominant (M∶F=3∶1). Histologically, the typical MCL is the majority (classical MCL: variant type MCL=48 cases:12 cases) . Fifty cases were classified into non-complete FDC meshwork type MCL, and the remaining 10 cases were classified into the complete-FDC meshwork type MCL group. Patients with classical MCL were more than 60 years old. The coexistent lesion sites both node and extranode in pathological subtype or structural subtype was the most common lesion sites. SOX11(+) MCL was common in classical MCL (P=0.040) and tended to be complete-FDC meshwork type MCL (P=0.086). The expression rate of MEF2B in MCL was 60.0%(36/60). This rate of MEF2B in classical type, complete-FDC meshwork type and SOX11(+) MCL was significantly higher than that variant type, no complete-FDC meshwork type, SOX11(-)MCL (P<0.05), respectively. There was no difference in clinical characteristics of MCL between MEF2B positive and negative groups. Compared with SOX11(-)MCL, the percentage of MEF2B expressed in tumor cells of SOX11(+)MCL was significantly higher (P=0.027). The expression of MEF2B was not related to the proliferation of tumor cells (P=0.341). There was no significant difference in the survival rate between different expression groups of MEF2B and SOX11 (P=0.304 and P=0.819, respectively). Only the mortality of variant type (blastoid/pleomorphic) MCL within 2 years was significantly higher than that of classical type MCL (P<0.05). Conclusions The expression of MEF2B in MCL is related to the pathological subtypes, structural subtypes and the expression of SOX11, but not to the proliferation and prognosis. The high mortality rate within 2 years is only found in variant MCL. However, the role of MEF2B in MCL needs to be further studied.

Objective:To retrospectively analyze the risk factors for the development of liver cancer in patients with hepatitis B-related liver cirrhosis (LC) treated and fully managed with long-term nucleos(t)ide analogues (NAs).Methods:The study subjects were derived from the follow-up cohort of chronic hepatitis B and liver cirrhosis who received antiviral therapy in the Department of Infectious Diseases of the First Affiliated Hospital of Guangxi Medical University from February 2004 to September 2019. LC patients who met the inclusion criteria were enrolled. The life-table method was used to calculate the incidence of liver cancer. Multivariable Cox regression model was used to analyze the risk factors that may affect the development of liver cancer in patients with LC. A subgroup analysis was conducted in liver cirrhotic patients who developed liver cancer to evaluate the effectiveness of antiviral treatment compliance. The 2 test was used for rate comparison. Results:The median follow-up time of 198 LC cases treated with NAs was 6.0 years (1.0-15.3 years). By the end of the visit: (1) 16.2% (32/198) of LC patients had developed liver cancer, and the cumulative incidence of liver cancer in 1, 3, 5, 7, and 9 years were 0, 8.9%, 14.3%, 18.6%, and 23.4%, respectively, with an average annual incidence of 3.1%. Among the 32 cases with liver cancer, 68.7% had developed small liver cancer (22/32). (2) Univariate Cox model analysis showed that the development of liver cancer was related to four factors, i.e., the presence or absence of LC nodules, whether the baseline was first-line medication, the family history of liver cancer, and patient compliance. The results of multivariate Cox model analysis showed that poor patient compliance and baseline non-first-line medication were risk factors for liver cancer. (3) The results of log-rank test subgroup analysis showed that the 5-year cumulative incidence of liver cancer in patients with hardened nodules was significantly higher than that of patients without hardened nodules (21.7% vs. 11.5%, P = 0.029). The 5-year cumulative incidence of liver cancer in patients with non-first-line drugs was significantly higher than that of patients with first-line drugs (22.0% vs.8.2%, P = 0.003). The 5-year cumulative incidence of liver cancer in patients with poor compliance was significantly higher than that of patients with good compliance (21.3% vs. 12.7%, P = 0.014). The 5-year cumulative incidence of liver cancer in patients with a family history of liver cancer was significantly higher than that of patients without a family history of liver cancer (22.3% vs. 8.1%, P = 0.006). (4) Compared with patients with poor compliance, patients with good compliance had higher HBV DNA negative serconversion rate (98.7% vs. 87.8%, P = 0.005), and a lower virological breakthrough rate (12.1% vs. 29.3%, P = 0.007). Conclusion:The long-term NAs antiviral therapy can reduce the risk of liver cancer, but it cannot completely prevent the development of liver cancer, especially in patients with a family history of liver cancer and baseline hardened nodules (high risk of liver cancer). Furthermore, the complete management can improve patient compliance, ensure the efficacy of antiviral therapy, and reduce the risk of liver cancer development, so to achieve secondary prevention of liver cancer, i.e., early detection, diagnosis and treatment.

Objective:To retrospectively analyze the serological, virological, biochemical, liver histological status and clinical outcomes in HBeAg-negative chronic hepatitis B (CHB) patients with low HBV viral load, and to explore the necessity of antiviral therapy for these patients.Methods:A total of 99 HBeAg-negative CHB patients with HBV DNA level < 4 lg copies/ml who performed liver biopsy at the baseline were enrolled from the follow-up cohort. Among them, 23 cases received the second liver biopsy during follow-up. The relationships among the degree of inflammation and fibrosis of liver tissues, the status of HBsAg and HBcAg, age, gender, family history, HBV DNA load, serological markers and other indicators were analyzed. The pathological differences between two liver biopsy examinations were compared. The effect of nucleos(t)ide analogues (NAs) treatment on patient’s clinical outcomes were analyzed. For multivariate analysis, a binary logistic regression model was performed. Log-rank test was used to compare the cumulative incidence of hepatocellular carcinoma (HCC) in NAs-treated and non-NA streated patients.Results:Baseline liver histology status showed that 58.6% (58/99) patients had obvious liver tissue damage in their baseline liver tissue pathology (G≥2 and /or S≥2). Univariate logistic regression analysis showed that a liver cirrhosis (LC) family history, a HBsAg-positive family history, baseline alanine aminotransferase and aspartate aminotransferase levels were positively correlated factors for liver tissue damage. Multivariate logistic regression analysis showed that a LC family history was the main risk factor for liver tissue damage. Twenty-three cases had received a second liver biopsy after an interval of 4.5 years. In 10 untreated cases, the second liver biopsy results showed the rate of obvious liver tissue damage (G≥2 and/ or S≥2) increased from 50.0% to 90.0%. In the other 13 cases who received NAs treatment, the second liver biopsy showed improvement in liver histology, and the rate of obvious liver tissue damage decreased from 61.5% to 46.2%. The 5-year HCC cumulative incidence in non-NAs-treated patients was significantly higher than that of in NAs-treated patients (17.7% vs. 3.8%, P = 0.046). Conclusion:For most HBeAg-negative CHB patients with low viral load, liver tissue pathology result suggests that it meets the indications for antiviral therapy, especially in patients with a LC familial history. Without antiviral therapy, liver tissue damage for these patients will progressively worse with the high incidence of HCC. Therefore, it is suggested that antiviral therapy should be started as soon as possible for the HBeAg-negative CHB patients with low viral load regardless of the alanine aminotransferase level, especially in patients over 30 years-old with a LC or HCC family history.

Objective To evaluate the protective effect of pterostilbene against ultraviolet B (UVB)-induced acute damage in HaCaT cells,and to explore related mechanisms.Methods The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazo1ium (MTS) assay and flow cytometry were performed to estimate the proliferative activity and the apoptosis and necrosis rate of HaCaT cells treated with different concentrations of pterostilbene respectively,so as to screen the non-toxic concentration of pterostilbene.HaCaT cells were randomly divided into several groups:normal control group receiving no treatment,UVB group irradiated with 57 mJ/cm2 UVB,3 pterostilbene groups treated with 2.44,4.88 and 9.75 μmol/L pterostilbene respectively for 24 hours,3 pterostilbene + UVB groups treated with 2.44,4.88 and 9.75 μmol/L pterostilbene respectively for 24 hours followed by UVB radiation.Western blot analysis was conducted to detect changes of the transcription factor NF-E2-related factor 2 (Nrf2) expression in cell nuclei and cytoplasm before and after the treatment with pterostilbene and UVB,quantitative PCR to determine the mRNA expression of catalase and superoxide dismutase in the HaCaT cells,and enzyme-linked immunosorbent assay (ELISA) to evaluate the activity of catalase and superoxide dismutase.Results MTS assay and flow cytometry showed that 2.44,4.88 and 9.75 μmol/L pterostilbene had non-toxic effect on HaCaT cells.The protein expression of Nrf2 in the nuclei and cytoplasm in the normal control group was 1.03 ± 0.08 and 1.04 ± 0.11 respectively.Compared with the normal control group,the protein expression of Nrf2 in the nuclei and cytoplasm experienced no significant changes in the 2.44-,4.88-and 9.75-μmol/L pterostilbene groups,and the UVB group showed similar protein expression of Nrf2 in the cytoplasm,but significantly increased protein expression of Nrf2 in the nuclei (1.77 ± 0.08,q =17.24,P ＜ 0.01).Compared with the normal control group and UVB group,the 2.44-,4.88-and 9.75-μmol/L pterostilbene + UVB groups all showed significantly lower protein expression of Nrf2 in the cytoplasm (0.86 ± 0.10,0.87 ± 0.11 and 0.46 ± 0.11 respectively,all P ＜ 0.05),but significantly higher protein expression of Nrf2 in the nuclei (2.38 ± 0.11,2.57 ± 0.11 and 2.07 ± 0.13,all P ＜ 0.01).As qPCR showed,UVB radiation could significantly inhibit the mRNA expression of CAT (P ＜ 0.05),but had no obvious effect on the mRNA expression of SOD (P ＞ 0.05).The mRNA expression of CAT and SOD experienced no significant changes in the 2.44-,4.88-and 9.75-μmol/L pterostilbene groups compared with the normal control group (P ＞ 0.05).However,2.44,4.88 and 9.75 μmol/L pterostilbene could significantly reduce the inhibitory effect of UVB radiation on the mRNA expression of CAT (P ＜ 0.05) and up-regulate the mRNA expression of SOD in the pterostilbene + UVB groups (P ＜ 0.05).ELISA revealed that UVB radiation could inhibit the activity of CAT and SOD in the HaCaT cells (both P ＜ 0.001),while 2.44,4.88 and 9.75 μmol/L pterostilbene could reduce the inhibitory effect of UVB radiation on the activity of CAT and SOD (all P ＜ 0.05).However,the activity of CAT and SOD were still lower in the 2.44-,4.88-and 9.75-μmol/L pterostilbene + UVB groups than in the normal control group (P ＜ 0.05).Conclusion Pterostilbene can prevent UVB-induced acute damage in HaCaT cells by activating the Nrf2 pathway and up-regulating the expression of the downstream antioxidant enzymes CAT and SOD.