Salidroside prevents PM2.5-induced BEAS-2B cell apoptosis via SIRT1-dependent regulation of ROS and mitochondrial function.

PM2.5 is a harmful air pollutant currently threatening public health. It has been closely linked to increased morbidity of bronchial asthma and lung cancer worldwide. Salidroside (Sal), an active component extracted from Rhodiola rosea, has been reported to ameliorate the progression of asthma. However, there are few studies on the protective effect of salidroside on PM2.5-induced bronchial epithelial cell injury, and the related molecular mechanism is not clear. Here, we aimed to explore the protective effect and related mechanism of Sal on PM2.5 bronchial injury. We chose 50 µg/mL PM2.5 for 24 h as a PM2.5-induced cell damage model. After that BEAS-2B cells were pretreated with 40, 80, 160 µM Sal for 24 h and then exposed to 50 µg/mL PM2.5 for 24 h. We found that Sal pretreatment significantly inhibited the decrease of cell viability induced by PM2.5. Sal was effective in preventing PM2.5-induced apoptotic features, including Ca2+ overload, the cleavages of caspase 3, and the increases in levels of caspase 9 and Bcl-2-associated X protein (Bax), ultimately, Sal significantly inhibited PM2.5-induced apoptosis. Sal improved mitochondrial membrane potential, inhibited the release of cytochrome c from the mitochondria to cytoplasm. Sal alleviated ROS production, decreased the level of MDA, prevented the reduction of CAT, SOD and GSH-Px and increased the expression of NF-E2-related factor 2 (Nrf2), HO-1 and superoxide dismutase 1 (SOD1) in cells exposed to PM2.5. Furthermore, Sal improved the decrease of SIRT1 and PGC-1 α expression levels caused by PM2.5. In addition, inhibition of SIRT1 by EX527 (SIRT1 inhibitor) reversed the protective effects of Sal, including the decrease of ROS level, the increase of membrane potential level and the decrease of apoptosis level. Thus, Sal may be regarded as a potential drug to prevent PM2.5-induced apoptosis of bronchial epithelial cells and other diseases with similar pathological mechanisms.

[Renal injury induced by cadmium chloride and the protective effect of vitamin C in mice].

OBJECTIVE: To investigate the renal injury induced by cadmium chloride(CdCl_2) and the protective effect of vitamin C(VC) in mice. METHODS: Forty healthy clean grade male Kunming mice were randomly divided into 4 groups: control group(double distilled water gavage and intraperitoneal injection), VC group(200 mg/kg VC gavage and double distilled water intraperitoneal injection), CdCl_2 group(double distilled water gavage and 2 mg/kg CdCl_2 intraperitoneal injection), VC+CdCl_(2 )group(200 mg/kg VC gavage and 2 mg/kg CdCl_2 intraperitoneal injection). Exposure for 30 days.24 hours after the last exposure, the eyeballs were taken out for blood, and the renal tissue was immediately taken out to calculate kidney coefficient and then separate renal cells. The levels of reactive oxygen species(ROS) were detected by DCFH-DA kit and flow cytometry. Blood urea nitrogen(BUN), serum creatinine(Scr)and ß2 microglobulin(ß2-MG), cystatin C(Cys C), superoxide dismutase(SOD), glutathione peroxidase(GSH-Px), malondialdehyde(MDA), Caspase3 and Caspase9 kits were used to detect the corresponding indicators respectively. The contents of Cd~(2+) and Zn~(2+) in serum and kidney were detected by graphite furnace atomic absorption spectrometry. RESULTS: The levels of kidney coefficient and BUN, Scr, ß2-MG were 1.36±0.10, (19.34±0.63)mmol/L, (61.30±2.04)mmol/L and(1.02±0.10)g/mL respectively in CdCl_(2 )group, which were higher than those in the control group and VC group(P<0.05). The levels of the above four indexes in VC+CdCl_(2 )group were 1.09±0.10, (9.65±0.50)mmol/L, (41.85±1.27)mmol/L and(0.61±0.01)g/mL respectively, which were lower than those in CdCl_2 group(P<0.05). CdCl_2 exposure resulted in unclear glomerular contour, swelling of renal tubules, interstitial hyperemia, and exfoliated epithelial cells in the lumen. VC pretreatment could improve the above changes. The levels of Cd~(2+) in serum and renal tissue of mice in CdCl_2 group were(4.36±0.07)µg/L, (18.6±1.95)µg/g respectively, which were higher than that of control group and VC group(P<0.05), in VC+CdCl_2 group, the level were(2.12±0.06)µg/L and(2.18±0.09)µg/g, they were lower than that of CdCl_2 group(P<0.05). The level of serum Zn~(2+ )in CdCl_2 group was(11.35±1.03)µg/L, that was lower than control group(P<0.05). The level of serum Zn~(2+) in VC+CdCl_2 group was(26.98±3.13)µg/L, which was higher than that of CdCl_2 group(P<0.05). The levels of ROS, MDA, Caspase3 and Caspase9 in kidney tissue of mice in CdCl_2 group were(1.86±0.13), (4.78±0.15)nmol/mg, 1.50±0.24 and 1.69±0.17 respectively, which were higher than those in control group(P<0.05). And the level of GSH-Px was(261.3±23.36)U/mg, it was lower than that in control group(P<0.05). Compared with the CdCl_2 group, the levels of ROS, MDA, Caspase3 and Caspase9 in VC+CdCl_2 group decreased, and the level of GSH-Px increased, the difference was statistically significant(P<0.05). CONCLUSION: CdCl_2 exposure can lead to oxidative stress, damage of glomerulus and renal tubules, imbalance of zinc ion homeostasis, and damage of renal function. VC pretreatment can reduce the damage caused by CdCl_2 to a certain extent.

[Air fine particulate matter induced alveolar type â ¡ epithelial cell injury in rats].

OBJECTIVE: To investigate the damage of rat alveolar type II epithelial cells(RLE-6 TN) caused by air fine particulate matter(PM_(2.5)) and its related mechanism. METHODS: PM_(2.5) in the atmosphere of Weifang City in 2020 was collected and cell culture medium was used to prepare particulate suspension. RLE-6 TN cells were exposed to different concentrations(25, 50, 100, 200, 400 µg/mL) of particulate matter suspensions for 24 h. The morphological changes of RLE-6 TN cells were observed under inverted microscope, and the cell viability was determined by MTT method. The concentration of lactate dehydrogenase(LDH) in cell supernatant was determined by microplate method. DCFH-DA, Annexin V-FITC/PI, JC-1 probe and laser confocal fluorescence intensity were used to determine the levels of reactive oxygen species(ROS), apoptosis and mitochondrial membrane potential. Total superoxide dismutase(T-SOD), glutathione(GSH) and malondialdehyde(MDA) contents and activity levels in cells were determined by colorimetric method. Caspase-3 and Caspase-9 kit were used to detect the relative expression activity of apoptosis proteins. RESULTS: PM_(2.5) could lead to morphological changes of RLE-6 TN cells, enlarged cell space and decreased cell viability. Compared with the control group, there were statistically significant differences in each dose group(P<0.05). LDH concentration in the supernatant of ≥50 µg/mL infected group increased, and LDH concentration was ≥(377.82±29.84), which was significantly different from that of the control group(278.51±23.76)(P<0.05). The result of laser confocal detection of ROS showed that the intracellular green fluorescence increased gradually in the ≥50 µg/mL group, and the relative fluorescence intensity was ≥(2.77±0.18), which was statistically significant compared with the control group(P<0.05). The level of apoptosis was significantly increased compared with the control group(P<0.05). The level of mitochondrial membrane potential decreased gradually, and the level of mitochondrial membrane potential in the ≥25 µg/mL group was ≤(4.22±0.45), which was statistically different from that in the control group(6.16±0.49)(P<0.05). PM_(2.5) could reduce the levels of T-SOD and GSH, and the levels of T-SOD and GSH in ≥50 µg/mL exposed group were ≤(14.67±0.49) and ≤(433.29±39.24), respectively, significantly lower than those in control group((16.58±0.60) and(542.90±45.06))(P<0.05). MDA level increased with the increase of PM_(2.5) concentration. Compared with the control group(1.15±0.19), MDA level in ≥50 µg/mL exposed group was ≥(1.72±0.13), with statistical significance(P<0.05). The activity levels of Caspase-3 and Caspase-9 increased in ≥100 µg/mL group, and the activity levels were ≥(1.62±0.27) and ≥(1.23±0.06), respectively, compared with the control group, the differences were statistically significant(P<0.05). CONCLUSION: Exposure to a certain concentration of PM_(2.5) can induce oxidative stress of rat alveolar type II epithelial cells, reduce the membrane potential, and eventually lead to cell apoptosis.

[Protective effect of oleanolic acid on L02 hepatocyte injury induced by HgCl_2].

OBJECTIVE: To investigate the protective effect of oleanolic acid(OA) on HgCl_2 induced liver injury. METHODS: L02 cells were divided into four groups according to different treatment, control group(Con), oleanolic acid group(OA, 10 µmol/L), HgCl_2 group(HgCl_2, 40 µmol/L) and oleanolic acid + HgCl_2 group(OA + HgCl_2). Cells of control group were given serum-free medium, cells of OA group were pretreated with OA solution for 8 hours, cells of HgCl_2 group were exposed to HgCl_2 solution for 6 hours, cells of OA + HgCl_2 group were pretreated with OA solution for 8 hours, and then exposed to HgCl_2 solution for 6 hours. MTT assay was used to detect cell viability. Laser confocal scanning was used to detect JC-1 probe fluorescence intensity to determine mitochondrial membrane potential. DCFH-DA fluorescence probe combined with flow cytometry was used to detect reactive oxygen species(ROS) level. Annexin V/PI double staining method combined with flow cytometry was used to determine cell apoptosis rate. Catalase(CAT), total superoxide dismutase(T-SOD), glutathione(GSH), malondialdehyde(MDA), Caspase 3 and Caspase 9 kits combined with enzyme labeled instrument were used to determine their activity or content respectively. RESULTS: Compared with the control group, 40 µmol/L HgCl_2 could significantly reduce cell viability, the level was 0.52±0.03(P<0.05), OA pretreatment could significantly inhibit the decrease of cell viability induced by HgCl_2, the level was 0.86±0.05(P<0.05). The result of mitochondrial membrane potential detection showed that cell exposed to 40 µmol/L HgCl_2 significantly reduced the intensity of red fluorescence, and the ratio of red to green fluorescence was 0.23±0.02(P<0.05). OA pretreatment significantly increased red fluorescence, and the ratio of red fluorescence to green fluorescence was 1.32±0.08, which was significantly higher than that of HgCl_2(P<0.05). After exposure to 40 µmol/L HgCl_2, the relative fluorescence intensity of ROS was 1.21±0.07, the apoptosis rate was about 8%, the activity levels of Casepase 3 and Casepase 9 were 3.11±0.20 and 2.94±0.17, respectively, which were all significantly higher than those in the control group(P<0.05). OA pretreatment could significantly alleviate the changes of the above indexes, and the difference was statistically significant compared with HgCl_2 group(P<0.05). The level of T-SOD in HgCl_2 group was(7.68±0.39)U/mL, which was significantly lower than that in control group(P<0.05). Compared to the control group, the level of MDA was significantly increased to(4.99±0.26)nmol/mg(P<0.05). OA pretreatment significantly increased level of T-SOD and decreased the level of MDA, the levels were(13.97±0.71)U/mL and(3.01±0.17)nmol/mg, respectively(P<0.05). CONCLUSION: A certain concentration of HgCl_2 can induce hepatocyte damage. OA pretreatment may reduce cell damage by improving oxidative stress.

A femtomolar level and highly selective 17ß-estradiol photoelectrochemical aptasensor applied in environmental water samples analysis.

Driven by the urgent demand of determining low level of 17ß-estradiol (E2) present in environment, a novel and ultrasensitive photoelectrochemical (PEC) sensing platform based on anti-E2 aptamer as the biorecognition element was developed onto CdSe nanoparticles-modified TiO2 nanotube arrays. The designed PEC aptasensor exhibits excellent performances in determination of E2 with a wide linear range of 0.05-15 pM. The detection limit of 33 fM is lower than the previous reports. The aptasensor manifests outstanding selectivity to E2 while used to detect seven other endocrine disrupting compounds that have similar structure or coexist with E2. The superior sensing behavior toward E2 can be attributed to the appropriate PEC sensing interface resulting from the preponderant tubular microstructure and excellent photoelectrical activity, the large packing density of aptamer on the sensing interface, as well as the high affinity of the aptamer to E2. The PEC aptasensor was applied successfully to determine E2 in environmental water samples without complicate sample pretreatments, and the analytical results showed good agreement with that determined by HPLC. Thus, a simple and rapid PEC technique for detection low level of E2 was established, having promising potential in monitoring environmental water pollution.

Investigation of the indoor 222Rn and 220Rn levels in the residential environment and estimation of the annual effective radiation dose for ordinary residents.

To evaluate the health risk of radon and its progeny, a large amount of accurate monitoring data is needed according to the theory and practice of health risk assessment. However, the indoor radon levels in different regions in China and worldwide reveal temporal and spatial variations. In addition, the residents living in different areas follow distinct living modes. Therefore, it is recommended and accepted by many researchers to detect the radon level in local areas and subsequently conduct health risk assessments based on local detection data. In this study, 21 bedrooms of households in Weifang city were selected, and the indoor 222Rn and 220Rn levels were detected with RAD7 radon detector in winter, while the annual effective radiation dose was calculated for ordinary residents in Weifang city. Our investigation showed that the 24- and 12-hour average levels of 222Rn were 35.7±15.2 Bq/m3 and 36.2±15.8 Bq/m3, respectively. The 24- and 12-hour average levels of 220Rn were 30.4±12.3 Bq/m3 and 22.4±11.6 Bq/m3, respectively. There were significant differences in the average levels of 222Rn and 220Rn between floors. The estimated annual effective radiation dose received by ordinary residents in Weifang city was 1.7193 mSv, of which 0.9479 mSv originated from 222Rn and its progeny and 0.7714 mSv originated from 220Rn and its progeny, accounting for 55.1% and 44.9%, respectively, of the total dose. Our findings suggest that 220Rn should not be ignored by local residents in Weifang city, and more attention should be paid to 220Rn in future research.

A simple and highly selective electrochemical label-free aptasensor of 17ß-estradiol based on signal amplification of bi-functional graphene.

In the present work, a convenient signal-on electrochemical label-free aptasensor for 17ß-estradiol (E2), a typical steroidal hormones endocrine disrupting chemicals, was proposed. 6-mercapto-1-hexanol (MCH) self-assembled monolayer (SAM) modified Au (MCH/Au) electrode was used as the substrate electrode. Graphene is used with bi-functions, not only to adsorb E2 binding aptamer, serving as the recognition element to E2, but also to be assembled onto MCH/Au electrode when sensing E2, to controllably turn on the electron transfer (eT), and further indicate the signal to E2 concentration. With the synergistic effect of DNase I enzyme, highly sensitive detection of E2 was achieved at this aptasensing system, with a linear range from 0.07 to 10 pM and a detection limit of 50 fM. An outstanding selectivity towards E2 was proven for the sensing system by simultaneously detecting 100-fold potential co-existing interferences. The stability and reproducibility were also evaluated to be satisfactory. Spiked real water analysis further indicated its reliability and potential in practical environmental monitoring.

A highly sensitive and wide-ranged electrochemical zinc(II) aptasensor fabricated on core-shell SiO2-Pt@meso-SiO2.

In this work, bi-functional SiO2-Pt@meso-SiO2 core-shell nanoparticles were designed to prepare a highly sensitive and selective electrochemical zinc(II) aptasensor. This core-shell structure boasts its SiO2 mesoporous shell and the inside Pt nanoparticles. SiO2 mesoporous shell can fix aptamer without affecting its configuration and can admit electrolyte through the shell. SiO2 core inside can be the substrate of larger amount of Pt nanoparticles that improve the conductivity of the modified electrode dramatically. Due to the application of such a special bi-functional structure and the aptamer's strong combination capacity with Zn(2+), Zn(2+) is pre-enriched onto the electrode effectively and specifically, so that it can be determined sensitively and selectively. Results have shown that the zinc(II) aptasensor can be utilized at a wide linear working range from 100 pM to 50 µM and a low detection limit of 65 pM, which makes it practical in both biological samples and environment monitoring. This method has been successfully applied in Zn(2+) monitoring in human blood and disrupted human cells (MCF-7).