Short photoperiod inhibited gonadal growth and elevated hypothalamic Dio3 expression unrelated to promoter DNA methylation in young Brandt's voles.

Photoperiod, the length of daylight, has a significant impact on the physiological characteristics of seasonal breeding animals, including their somatic and gonadal development. In rodents, expression of deiodinase type II (Dio2) and III (Dio3) in the hypothalamus is crucial for responding to photoperiodic signals. However, research on the photoperiodism of hypothalamic gene expression and the corresponding regulatory mechanism in Brandt's voles living in the Mongolian steppes is limited. In this study, we gradually changed day length patterns to simulate spring (increasing long photoperiod, ILP) and autumn (decreasing short photoperiod, DSP). We compared the somatic and gonadal development of voles born under ILP and DSP and the expression patterns of five reproduction-related genes in the hypothalamus of young voles. The results showed that DSP significantly inhibited somatic and gonadal development in both female and male offspring. Compared with ILP, Dio3 expression was significantly upregulated in the hypothalamus under DSP conditions and remained elevated until postnatal week 8 in both males and females. However, there was no significant difference in the methylation levels of the proximal promoter region of Dio3 between ILP and DSP, suggesting that methylation in the proximal promoter region may not be involved in regulating the expression of Dio3. These findings suggest that hypothalamic expression of Dio3 plays a key role in the photoperiodic regulation of gonadal activity in Brandt's voles. However, it appears that CpGs methylation in the promoter region is not the main mechanism regulating Dio3 expression.

Pitx2 suppression at meiotic stages associates with seasonal inhibition of testis development in Rattus norvegicus caraco.

The bicoid-related transcription factor 2 (Pitx2) plays a crucial role in the development of many organs and tissues by affecting the mitotic cell cycle. Postnatal testis development is related to mitosis and meiosis in multiple cell types, but the role of Pitx2 gene in seasonal inhibition of testicular development remains unknown in rodents. We analyzed PITX2 protein and Pitx2 mRNA expression features using both laboratory and wild male Rattus norvegicus caraco. In postnatal testicle of laboratory colony, we found that PITX2 was expressed in Leydig cells, pachytene spermatocytes, round spermatids, and elongating spermatids rather than spermatogonia and leptotene/zygotene spermatocytes. Pitx2b expression significantly increased along with the occurrence of pachytene spermatocytes and round spermatids, while decreased along with the processes of elongated spermatids. In wild male rats with similar testes weight, a significantly suppressed Pitx2b expression occurred with an active meiotic stage in the inhibited testes in autumn and winter, compared with the normally developing testes in spring and summer. These results indicate that Pitx2b expression suppression plays a crucial role in the seasonal inhibition of testis development.

In situ synthesis of nitrogen doped carbon with embedded Co@Co3O4 nanoparticles as a bifunctional electrocatalyst for oxygen reduction and oxygen evolution reactions.

A novel electrocatalyst of core-shell structural Co@Co3O4 nanoparticles embedded in an N-doped carbon nanosheet (N-C) (Co@Co3O4/N-C) has been in situ synthesized via a simple pyrolysis and subsequent oxidative calcination. The catalyst exhibits superior bifunctional catalytic activity for the ORR and OER, which is attributed to the synergetic effect between Co and Co3O4 and the carbon layer structure.

[Effect of heparin pretreatment on the level of neutrophil extracellular traps of serum and lung tissue in septic mice].

OBJECTIVE: To investigate the influence of heparin pretreatment on serum and lung tissue level of neutrophil extracellular traps (NETs) in septic mice model and its molecular mechanism. METHODS: Ninety male C57BL/6J mice were randomly divided into control group (n = 30), lipopolysaccharides (LPS) group (n = 30, 30 mg/kg LPS in 100 ?L normal saline was intraperitoneally injected) and LPS+heparin group (n = 30, 8 U of heparin in 20 ?L normal saline was subcutaneously injected 30 minutes before the injection of LPS). Six hours later of LPS injection, blood was collected and lung tissue was harvested. Enzyme linked immunosorbent assay (ELISA) was used to assess the concentration of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and histones 2AX (H2AX), neutrophil elastase (NE), which reflected NETs concentration. PicoGreen fluorescent dyes was used to detect serum circulating free DNA (cf-DNA/NETs) concentration. The protein expression levels of H2AX and NE in lung tissue were examined by Western Blot. RESULTS: The serum concentrations of TNF-α, IL-6, H2AX, NE, cf-DNA/NETs, and the protein expression levels of H2AX and NE in lung tissue of septic mice were significantly higher than those of control group [TNF-α (ng/L): 133.0±14.1 vs. 2.7±1.0, IL-6 (ng/L): 3 911.2±189.2 vs. 298.9±52.5, H2AX (ng/L): 545.5±40.0 vs. 21.9±8.3, NE (µg/L): 6.48±0.12 vs. 0.47±0.15, cf-DNA/NETs (µg/L): 846.3±137.5 vs. 152.7±36.4, H2AX protein (gray value): 1.14±0.09 vs. 0.68±0.04, NE protein (gray value): 0.56±0.03 vs. 0.32±0.04, all P < 0.05]. After heparin pretreatment, levels of serum TNF-α, H2AX, NE, cf-DNA/NETs, and protein expression levels of H2AX and NE in lung tissue were significantly reduced [TNF-α (ng/L): 83.2±7.6 vs. 133.0±14.1, H2AX (ng/L): 435.0±39.0 vs. 545.5±40.0, NE (µg/L): 4.26±0.17 vs. 6.48±0.12, cf-DNA/NETs (µg/L): 606.5±73.9 vs. 846.3±137.5, H2AX protein (gray value): 0.91±0.03 vs. 1.14±0.09, NE protein (gray value): 0.42±0.03 vs. 0.56±0.03, all P < 0.05], but no significant change was found in IL-6 (ng/L: 3 919.9±166.6 vs. 3 911.2±189.2, P > 0.05). CONCLUSIONS: Heparin pretreatment could significantly decrease the level of NETs in serum and lung tissue, and can be the potential mechanism of its organ protection in sepsis.

[Heparin reduces endothelial cell damage induced by neutrophil extracellular traps].

OBJECTIVE: Clarify the effect of neutrophil extracellular traps (NETs) on endothelial cell injury, and investigate whether the heparin can exert a protective effect on endothelial cells by reducing the endothelial cell injury induced by NETs. METHODS: Neutrophils (PMN) were obtained from healthy human peripheral blood by Percoll-Histopaque density gradient centrifugation, and was stimulated with phorbol ester (PMA) to induce NETs. The qualitative and quantitative analysis of NETs was detected by immunofluorescence staining combined with fluorescence detector. The NETs were used to induce human umbilical vein endothelial cells (HUVEC) in vitro. Recombinant DNA hydrolytic enzymes (rhDNase) and heparin intervention were added respectively. The activity of HUVEC was measured by methyl thiazolyl tetrazolium (MTT) method after 6 hours. RESULTS: PMA can stimulate PMN to produce NETs. Immunofluorescence staining showed the formation of reticular formation around the PMN. The concentration of cell-free DNA in the supernatant of PMN stimulated by PMA was significant increased compared with the control group through the detection of PicoGreen fluorescent labeling instrument (2 hours: 119.62±14.83 vs. 24.27±0.67, 4 hours: 146.67±21.24 vs. 28.35±2.98, both P < 0.05). Application of NETs to stimulate the HUVEC, cell damage was dose dependent and inhibition rate increased gradually. The endothelial cell inhibition induced by NETs can be antagonized after adding rhDNase [10 µg/L NETs: (8.65±0.51)% vs. (10.99±0.35)%, 20 µg/L NETs: (14.85±0.43)% vs. (16.85±0.49)%, 30 µg/L NETs: (26.06±3.51)% vs. (27.54±0.62)%, all P < 0.05]. Heparin with different concentrations were added into the experimental group (0.01, 0.1, 1, 10 kU/L). We found that the endothelial cell inhibition rate decreased compared with control group [10 µg/L NETs: (8.96±0.70)%, (5.32±1.36)%, (0.70±0.30)%, (0.75±0.20)% vs. (10.99±0.35)%; 20 µg/L NETs: (15.57±0.62)%, (13.28±0.65)%, (6.91±0.15)%, (5.86±0.17)% vs. (16.85±0.49)%; 30 µg/L NETs: (30.49±0.74)%, (29.41±1.41)%, (23.45±0.75)%, (21.72±1.52)% vs. (27.54±0.62)%, all P < 0.05]. CONCLUSIONS: NETs can induce endothelial cell injury, and the injury degree was increased with the concentration of NETs. Heparin can reduce endothelial cell injury induced by NETs, which may be a potential mechanism for the protective effect of heparin on sepsis.