Effect of diosmetin on ferroptosis of hippocampal cells in rats with bacterial meningitis and the mechanism of SIRT1-Nrf2 signaling pathway / 中华行为医学与脑科学杂志

Objective:To explore the effect and mechanism of diosmetin (Dio) on neuronal ferroptosis in rats with bacterial meningitis (BM).Methods:Male SD rats aged 6-7 weeks of SPF grade were selected for the experiment. The BM model was established by injecting group B hemolytic streptococcus into the cisterna magna of cerebellum. Sixty BM model rats were successfully modeled and divided into model group, low-dose Dio group, medium-dose Dio group, high-dose Dio group and inhibitor group according to the random number table method, with 12 rats in each group. Another 12 weight-matched rats were taken as the control group.The rats in the low-dose Dio group, medium-dose Dio group, high-dose Dio group and the inhibitor group were intragastrically administered with Dio at 50 mg/kg, 100 mg/kg, 200 mg/kg and 200 mg/kg, respectively. The rats in the control group were intragastrically administered with an equal volume of 0.9 % sodium chloride solution. On the day of intragastric administration, the rats in the inhibitor group were intraperitoneally injected with SIRT1 pathway inhibitor EX527 (10 mg/kg), and the rats in the other groups were injected with an equal volume of 0.9% sodium chloride solution. The above interventions were performed once a day for 28 consecutive days. Loeffler neurological score was used to evaluate the neurological impairment in rats. Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in cerebrospinal fluid of rats were detected by ELISA. The number of white blood cells in cerebrospinal fluid was detected by a blood cell analyzer. Glutathione (GSH) was detected by micro-enzyme labeling method, malondialdehyde (MDA) was detected by thiobarbituric acid colorimetric method, reactive oxygen species(ROS) was detected by colorimetry, and Fe 2+ level was detected by ferrozine method. Hematoxylin-eosin staining, Prussian blue staining and TUNEL staining were used to observe the pathological damage, iron accumulation and apoptosis in the hippocampus, respectively.Western blot was applied to measure the expression of transferrin (Tf), proliferating cell nuclear antigen (PCNA), Bcl-2-associated X protein (Bax), caspase-3 and SIRT1/Nrf2/HO-1/Gpx4 signaling pathway proteins. Graphpad Prism 9.0 was used for data analysis. One-way ANOVA was used for statistical analysis, and SNK- q test was used for further pairwise comparisons. Results:(1) There was a statistically significant difference in neurological function scores among the 6 groups of rats ( F=125.451, P<0.001). The neurological function score of the model group was lower than that of control group, while the neurological function scores of the low-dose Dio group, medium-dose Dio group, and high-dose Dio group were higher than those of the model group (all P<0.05). The neurological function score of the inhibitor group ((2.57±0.26)) was lower than that of high-dose Dio group ((4.34±0.48)) ( P<0.05). (2) There were statistically significant differences in the levels of IL-6, TNF-α and the number of white blood cells in the cerebrospinal fluid of rats among the 6 groups ( F=127.817, 102.413, 180.967, all P<0.001). The levels of IL-6, TNF-α and the number of white blood cells in model group were higher than those of control group(all P<0.05). The levels of IL-6, TNF-α and the number of white blood cells in low-dose Dio group, medium-dose Dio group and high-dose Dio group were lower than those of model group (all P<0.001), and those in inhibitor group were all higher than those in high-dose Dio group(all P<0.001). (3) There were statistically significant differences in iron deposition rate and neuronal apoptosis rate among the 6 groups of rats ( F=90.857, 88.835, both P<0.001). The iron deposition rate ((18.37±3.14)%) and neuronal apoptosis rate ((27.58±2.63)%) in the inhibitor group were higher than those in the high-dose Dio group ((6.35±1.08)%, (14.02±1.87)%) (both P<0.05). (4) The levels of GSH, ROS, MDA, and Fe 2+ in the hippocampus of the 6 groups of rats showed statistically significant differences ( F=54.465, 106.453, 55.969, 105.457, all P<0.001). The GSH content in the inhibitor group ((103.48±8.76) mmol/g) was lower than that in the high-dose Dio group ((133.97±10.54) mmol/g), while the contents of ROS, MDA, Fe 2+ ((225.17±16.32) μmol/mg, (10.73±1.58) μmol/mg, (62.71±5.43) μg/g) were higher than those of the high-dose Dio group ((131.87±11.67) μmol/mg, (4.35±0.87) μmol/mg, (34.86±2.95) μg/g) (all P<0.05). (5)There were statistically significant differences in the protein levels of Tf, PCNA, Bax, caspase-3, SIRT1, Nrf2, HO-1 and Gpx4 in the hippocampus of the 6 groups of rats ( F=120.179, 107.568, 157.265, 98.031, 90.932, 52.283, 59.424, 114.539, all P<0.001). The protein levels of Tf, Bax and caspase-3 in the hippocampus of inhibitor group were higher than those of the high-dose Dio group, while the protein levels of PCNA, SIRT1, Nrf2, HO-1, Gpx4 were lower than those of the high-dose Dio group (all P<0.05). Conclusion:Diosmetin can activate SIRT1/Nrf2/HO-1/Gpx4 signaling pathway, thereby inhibiting neuronal ferroptosis in BM rats.

Beyond diabetes mellitus: role of metformin in non-muscle-invasive bladder cancer

INTRODUCTION@#Usage of metformin is associated with improved survival in lung, breast and prostate cancer, and metformin has been shown to inhibit cancer cell growth and proliferation in in vitro studies. Given the lack of clinical data on metformin use in patients with bladder cancer, we aimed to evaluate the role of metformin in their oncological outcomes.@*METHODS@#Medication use data from a prospectively maintained database of 122 patients with non-muscle-invasive bladder cancer treated with intravesical Bacille Calmette-Guerin (BCG), who were recruited under a randomised, double-blinded, controlled clinical trial, was collected and analysed. Kaplan-Meier curves were used to assess overall survival (OS) and disease-specific survival (DSS).@*RESULTS@#At a median follow-up duration of 102 (range 3-357) months, 53 (43.4%) patients experienced disease recurrence and 21 (17.2%) experienced disease progression. There was no significant difference in mortality between patients with and without diabetes mellitus. There was significant difference in OS between patients without diabetes mellitus, patients with diabetes mellitus on metformin and patients with diabetes mellitus but not on metformin (p = 0.033); patients with diabetes mellitus on metformin had the best prognosis. Metformin use was associated with significantly lower DSS (p = 0.042). Other oral hypoglycaemic agents, insulin or statins were not associated with disease recurrence or progression.@*CONCLUSION@#Metformin use was associated with improved oncological outcomes in patients with non-muscle-invasive bladder cancer treated with intravesical BCG. Prospective studies with larger patient populations are needed to validate the role of metformin as potential therapy for bladder cancer.

Optimising utilisation of kidneys from very young deceased donors: the technique of en bloc kidney transplantation

Kidneys of paediatric deceased donors were previously considered suboptimal for older recipients. An 18-month-old deceased donor was made available via Singapore's Medical (Therapy, Education and Research) Act. To the best of our knowledge, she is the youngest local donor. We herein report a case of successful kidney transplantation, using the en bloc technique, to a 15-year-old girl with renal failure secondary to bilateral cystic dysplastic kidney.