Roles of 12-Lipoxygenase and Its Interaction with Angiotensin II on p21 and p27 Expression in Diabetic Nephropathy.

BACKGROUND: 12-Lipoxygenase (12-LO) and angiotensin II (Ang II) are involved in the development of diabetic renal hypertrophy, in which cyclin-kinase inhibitors, p21 and p27 play pivotal roles. Here, we study the effects of 12-LO and its interaction with Ang II on glomerular p21 and p27 expression in diabetic conditions. METHODS: Models used in the current study include glomerular mesangial cells (MCs); and glomeruli from (1) type 2 diabetic db/db mice; (2) type 2 diabetic rats induced by high-fat diet feeding followed by streptozotocin injection; (3) 12-LO knockout (12-LOKO) mice; and (4) normal rats infused with Ang II or 12(S)-hydroxyeicosatetraenoic acid (12[S]-HETE, arachidonic acid metabolite of 12-LO). RESULTS: The protein expression levels of p21 and p27 were increased in high glucose-stimulated MCs and in glomeruli isolated from db/db mice. In type 2 diabetic rats, cinnamyl-3,4-dihydroxy-α-cynanocinnamate (inhibitor of 12-LO) attenuated the increases in glomerular p21 and p27 protein expression, while in normal rats, 12(S)-HETE injection increased glomerular p21 and p27 expression. 12(S)-HETE and Ang II were mutually stimulated in glomeruli. Glomerular p21 and p27 expression were decreased in 12-LOKO mice compared to levels in control mice, and Ang II stimulation increased the protein expression of p27 in control but not 12-LOKO mice. Ang II stimulation had no effect on p21 protein expression in 12-LOKO mice. CONCLUSION: 12-LO is involved in diabetic renal hypertrophy via the induction of p21 and p27 protein expression and interacts with Ang II to induce p27 upregulation in diabetes. The current results suggest a potential amplifying loop in the pathogenesis of diabetic nephropathy.

Cell Cycle Arrest as a Therapeutic Target of Acute Kidney Injury.

The current lack of complete understanding of the pathogenesis of acute kidney injury (AKI) is a significant barrier to its early diagnosis and treatment. Cell cycle arrest plays an important role in the protection of renal tubular epithelial cells and maladaptive repair following AKI. G1 phase cell arrest serves as a protective mechanism following AKI, avoiding replication of damaged DNA. Insulinlike growth factor-binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinase-2 (TIMP-2) are closely associated with G1 cell cycle arrest during the very early phase of cellular damage and can serve as an ideal biomarker to predict AKI. However, sustained cell cycle arrest after severe AKI may result in cell senescence and maladaptive repair, with typical characteristics of the development of cell cycle arrest in the gap 2 (G2) or mitotic (M) phase. Markers of cell cycle arrest signal and spread the "alarm" from the site of injury to adjacent cells in an autocrine or paracrine manner, giving rise to abnormal amplification and release of profibrogenic factors, activation of pericytes/perivascular fibroblasts, and eventually fibrosis. Therefore, cell cycle regulation has become a potentially new target for the prevention and treatment of AKI. In this review, we summarize the characteristics of the cell cycle following AKI and the markers of cell cycle arrest that enable the early detection of AKI. We also discuss how to prevent the progression of chronic kidney disease (CKD) by regulating cell cycle arrest.

Renal protective effect of sirtuin 1.

Silent information regulator 2 (Sir2) is a nicotinamide adenine dinucleotide- (NAD(+)-) dependent deacetylase. The homology of SIRT1 and Sir2 has been extensively studied. SIRT1 deacetylates target proteins using the coenzyme NAD(+) and is therefore linked to cellular energy metabolism and the redox state through multiple signalling and survival pathways. During the past decade, investigators have reported that SIRT1 activity is essential in cancer, neurodegenerative diseases, diabetes, cardiovascular disease, and other age-related diseases. In the kidneys, SIRT1 may inhibit renal cell apoptosis, inflammation, and fibrosis. Therefore its activation may also become a new therapeutic target in the patients with chronic kidney disease including diabetic nephropathy. In this paper, we would like to review the protective functions of sirtuins and the role of SIRT1 in the onset of kidney disease based on previous studies, including diabetic nephropathy, acute renal injury, chronic kidney disease as well as lupus nephritis.

[Quantitative prediction of soil salinity content with visible-near infrared hyper-spectra in northeast China].

Studying the spectral property of salinized soil is an important work, for it is the base of monitoring soil salinization by remote sense. To investigate the spectral property of salinized soil and the relationship between the soil salinity and the hyperspectral data, the field soil samples were collected in the region of Northeast China and then reflectance spectra were measured. The partial least squares regression (PLSR) model was established based on the statistical analysis of the soil salinity content and the reflectance of hyperspectra. The feasibility of soil salinity prediction by hyperspectra was decided by analyzed calibration model and independent validation. Models accuracy was also analyzed, which was established in the conditions of different treatment methods and different re-sampling intervals. The results showed that it was feasible to predict soil salinity content based on measured reflectance spectrum. The results also revealed that it was necessary to smooth measured hyperspectra for spectral prediction accuracy to be improved significantly after smoothing. The best model was established based on smoothed and log(l/x) transformed hyperspectra with high determination coefficients (R2) of 0.6677 and RPD = 1.61, which showed that this math transformation could eliminate noise effectively and so as to improve the prediction accuracy. The largest re-sampling interval is 8 nm that could meet the accuracy of the soil salinity prediction. Therefore, it provided scientific reference of monitoring soil salinization by remote sensing from satellite platform.

[Effect of cisplatin on apoptosis of spiral ganglion cell and expression of caspase-3 in mouse cochlea].

OBJECTIVE: To establish a mice model of cisplatin-induced ototoxicity, and to investigate the effect of cisplatin on apoptosis of spiral ganglion cell and expression of caspase-3 in mouse cochlea. METHODS: Terminal deoxynucleotidyl transferase-mediated nick end labeling method (TUNEL) was used to monitor the apoptosis of spiral ganglion cell. Envision method of immunohistochemistry was applied to detect the expression of caspase-3 in cochlea. Auditory brainstem response (ABR) was measured to observe the change of hearing. RESULTS: The weight and hearing of mice in different dose of cisplatin groups were declined significantly as compared with those of control group (P < 0.05, P < 0.01), and the TUNEL positive cell number and expression of caspase-3 were greater remarkably with the more cisplatin injected. CONCLUSION: A mouse model of cisplatin-induced ototoxicity can be established. Cisplatin can lead to the apoptosis of spiral ganglion cells, and caspase-3 has participated in this apoptosis process, which approves further that apoptosis might be one of the mechanisms of cisplatin ototoxicity.

[Estimates and affecting factors of soil organic carbon storages in Yunnan-Guizhou-Guangxi Region of China].

Soil organic carbon (SOC) plays a key role in the terrestrial eco-systems. However, there is a large variation in SOC estimates at regional and global scales. In order to improve the accuracy of SOC estimates, the SOC storage in Yunnan-Guizhou-Guangxi Region of China (include Yunnan Province, Guizhou Province and Guangxi Zhuang Municipality) was estimated using 798 soil profiles and 1:500 000 digitized soil map, and the dominant affecting factors on SOC density were also discussed employing stepwise regression and path analysis. Results showed that the SOC storages estimated in the 0-20 cm and 0-100 cm layers are 4.39 Pg and 10.91 Pg, respectively; and the corresponding SOC density are 56.2 Mg x hm(-2) and 139.8 Mg x hm(-2), respectively. The mean SOC density of Yunnan-Guizhou-Guangxi Region is higher than that of China. The environmental factors (including altitude, longitude, latitude, annual mean precipitation and annual mean temperature), soil parent materials and land use could explain 37.9% and 30.7% of the variability of SOC density to the upper 20 cm and 100 cm, respectively. The environmental factors are the dominant affecting factors of SOC density. The effect of temperature is more important than that of precipitation, and the temperature and precipitation mainly vary with altitude and latitude, respectively. Except for temperature and precipitation, there are also other factors varying with altitude, longitude and latitude significantly affect SOC density. And the effects of other factors are more important than that of precipitation.

[Multiple central clinical studies on the needling method for regulating wei and strengthening brain for treatment of insomnia].

OBJECTIVE: To observe the clinical therapeutic effect of the needling method for regulating wei and strengthening brain on insomnia. METHODS: Two hundred cases of insomnia were randomly divided into a test group and a control group, 100 cases in each group. The test group were treated with the needling method for regulating wei and strengthening brain with Baihui (GV 20), Dazhui (GV 14), Shenmai (BL 62), Zhaohai (KI 6) and ear points Yuanzhong, Shenmen selected; and in the control group, Sishencong (EX-HN 1), Shenmen (HT 7) and Sanyinjiao (SP 6) were selected. Acupuncture was given once daily for 15 days. Pittsburgh sleep quality index (PSQI) was used for scoring before and after treatment. RESULTS: The total effective rate was 89.0% in the test group and 65.0% in the control group with a very significant difference between the two groups (P<0.01); the difference of PSQI scores before and after was -9.15+/-5.68 in the test group and -5.64+/-5.73 in the control group, with a very significant difference before and after treatment in the two groups (P<0.01). CONCLUSION: The therapeutic effect of the needling method for regulating wei and strengthening brain on insomnia is better than that of normal needling method.