[The protective effect of different doses of dexamethasone on acute kidney injury induced by sepsis in mice].

OBJECTIVE: To investigate the effect of different doses of dexamethasone (DEX) on sepsis induced acute kidney injury (AKI). METHODS: One hundred and thirty healthy male Kunming mice were randomly divided into sham group, sepsis group, physiological-dose DEX group (0.12 mg/kg), stress-dose DEX group (1.2 mg/kg), and high-dose DEX group (12 mg/kg). The sepsis model was reproduced by cecal ligation and puncture (CLP) method. Histopathological changes in the kidney were observed at 24 hours and 48 hours after CLP. The expressions of glucocorticoid receptor-α (GR-α) in the kidney were detected by immunohistochemistry. The levels of GR-α mRNA and nuclear factor-ΚB (NF-ΚB) mRNA were determined by real-time polymerase chain reaction (PCR). The levels of tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) in the plasma were measured by enzyme linked immunosorbent assay (ELISA). RESULTS: Compared with sham group mice, sepsis mice showed serious impairment in renal tubules. The mRNA and protein expression of GR-α were decreased, and NF-ΚB mRNA, plasma TNF-α and IL-1ß were elevated. Compared with sepsis group, the histopathological changes in the kidney were mitigated with different levels in groups treated with different doses of DEX. GR-α protein and mRNA were up-regulated, NF-ΚB mRNA and plasma TNF-α, IL-1ß were down-regulated obviously. The best effect could be seen in physiological DEX group [AKI score: 24 hours 1.480±0.334 vs. 3.040±0.517, 48 hours 1.840±0.167 vs. 3.400±0.400; GR-α protein (A value): 24 hours 0.102±0.009 vs. 0.088±0.005, 48 hours 0.103±0.008 vs. 0.085±0.006; GR-α mRNA: 24 hours 0.0400(0.0300, 0.0400) vs. 0.0100(0.0093, 0.0100), 48 hours 0.0350(0.0300, 0.0475) vs. 0.0100(0.0010, 0.0138); NF-ΚB mRNA: 24 hours 0.009±0.001 vs. 0.012±0.000,48 hours 0.011±0.000 vs. 0.013±0.001; TNF-α: 24 hours 105.84±3.84 ng/L vs. 135.52±4.49 ng/L, 48 hours 111.35±3.67 ng/L vs. 141.22±4.46 ng/L; IL-1ß: 24 hours 45.71±2.93 ng/L vs. 64. 12±3.62 ng/L, 48 hours 57.04±3.04 ng/L vs. 74.87±3.67 ng/L; P<0.05 or P<0.01]. CONCLUSIONS: DEX given in physiological-dose could increase renal GR-α level and alleviate the sepsis induced kidney injury. The protective effect was much better than that of high dose DEX.

Prenatal immune challenge in rats increases susceptibility to seizure-induced brain injury in adulthood.

Maternal infection during pregnancy is associated with an increased risk of neurodevelopmental injury. Our aim was to investigate whether prenatal immune challenge could alter susceptibility to seizure-induced brain injury in adulthood. Pregnant Wistar rats were injected intraperitoneally with lipopolysaccharide (LPS) or normal saline (NS) at days 15 and 16 of gestation. At postnatal day 45, seizure susceptibility was assessed in response to lithium-pilocarpine (LiPC) in adult offspring. Four groups were studied, including normal control (NS-NS), prenatal inflammation (LPS-NS), adult seizure (NS-LiPC), and "two-hit" (LPS-LiPC) groups. Our results demonstrated that adult rat offspring of LPS-exposed dams showed significantly greater susceptibility to LiPC-induced seizures, as well as enhanced hippocampal neuronal injury after seizures. Furthermore, animals in the "two-hit" group performed significantly worse than those from the NS-LiPC group in the open field test and Morris water maze. Our findings suggest that prenatal immune activation can cause a long-lasting increase in seizure susceptibility and predispose the brain to the damaging effect of seizures later in life.

Selenoprotein S expression in the rat brain following focal cerebral ischemia.

Recent studies on cerebral ischemic stroke have demonstrated the importance of the inflammatory response. Ongoing inflammatory insults have been implicated as a secondary mechanism underlying neuronal injury induced by ischemia, and anti-inflammatory strategies have gained considerable interest. Selenoprotein S (SelS), which is an endoplasmic reticulum resident protein, is known to promote cell survival by regulating inflammation. Moreover, SelS has been shown to be responsive to ischemia in cultured astrocytes. A Finnish report revealed that a variation in the SelS gene locus is associated with a higher predisposition to ischemic stroke in humans, suggesting a crucial role for SelS in protection against brain ischemia. However, the time-course of SelS expression following cerebral ischemia in vivo remains unknown. In the present study, we show, for the first time, differential SelS expression from 3 h to 7 days after reperfusion in rats with transient focal cerebral ischemia induced by a 1-h middle cerebral artery occlusion. We found that the SelS protein level decreased in the ischemic core 3-7 days after reperfusion. Furthermore, SelS expression was upregulated in the ischemic penumbra adjacent to the ischemic core 3-7 days after reperfusion and is matched by reactive astrogliosis. Thus, we propose that the upregulation of Sels represents a reaction of astrocytes against inflammatory stimuli, and the findings of this study open a new chapter in the research of the interrelationships between SelS and cerebral ischemic stroke.

Neonatal immune challenge exacerbates seizure-induced hippocampus-dependent memory impairment in adult rats.

Our aim was to examine whether neonatal lipopolysaccharide (LPS) exposure is associated with changes in microglia and whether these alternations could influence later seizure-induced neurobehavioral outcomes. Male pups were first injected intraperitoneally with either LPS or saline on postnatal day 3 (P3) and postnatal day 5 (P5). Immunohistochemical analysis showed that LPS-treated animals exhibited increased microglia activation that persisted into adolescence. At P45, seizures were induced in rats by intraperitoneal injection of kainic acid (KA). Rats treated with LPS neonatally showed significantly greater proinflammatory responses and performed significantly worse in the Y-maze, Morris water maze, and inhibitory avoidance tasks after KA insult. Treatment with minocycline at the time of neonatal LPS exposure to block LPS-induced microglia alternation attenuated the exaggerated neuroinflammatory responses and alleviated memory impairment associated with the KA insult. Our findings suggest that neonatal immune activation can predispose the brain to exacerbated behavioral deficits following seizures in adulthood, possibly by priming microglia.

[Effect of XPA expression on the chemotherapy sensitivity of A549/DDP cells].

AIM: To investigate the influence on platinum-based chemotherapy sensitivity by silencing xeroderma pigmentosum group A (XPA) gene expression in non-small cell lung cancer (NSCLC) drug resistance cell lines (A549/DDP). METHODS: We detected the expression of XPA in lung normal and tumor tissues by immunohistochemistry, quantitative real-time PCR (qPCR) and Western blotting. We silenced XPA expression in A549/DDP cells by XPA-shRNA transfection, and detected the expression of XPA by qPCR and Western blotting. The cell sensitivity to cisplatin and the apoptosis of A549/DDP cells transfected with XPA-shRNA were determined by MTT assay. RESULTS: The expression of XPA was higher in NSCLC tissues than that in normal lung tissues. Silencing XPA gene increased the apoptosis and sensitivity of A549/DDP cells to cisplatin. CONCLUSION: Silencing XPA gene can partly reverse the cisplatin resistance in human cisplatin-resistant NSCLC cell line A549/DDP.

Danshensu protects vascular endothelia in a rat model of hyperhomocysteinemia.

AIM: To examine whether danshensu could protect vascular endothelia in a rat model of hyperhomocysteinemia. METHODS: The model was established by feeding rats with a methionine-rich diet (1 g·kg⁻¹·d⁻¹) for 3 months. Immediately following the discontinuation of methionine-rich diet, rats were treated with danshensu (67.5 mg·kg⁻¹·d⁻¹, po) or saline for 3 additional months. One group of rats receiving vitamin mixture (folic acid, vitamin B12 and vitamin B6) was included as a positive control. One group of rats not exposed to methionine-rich diet was also included as a blank control. The expression of tumor necrosis factor-alpha (TNF-alpha) and intercellular adhesion molecule-1 (ICAM-1) protein in the descending aorta was examined using immunohistochemistry and Western blot. Homocysteine and blood concentration of endothelin and nitric oxide (NO) was also examined. RESULTS: Methionine-rich diet resulted in accumulation of "foam cells", up-regulated expression of TNF-alpha and ICAM-1 in the descending aorta, and significantly increased serum homocysteine. Plasma endothelin concentration was significantly increased; NO was decreased. Danshensu treatment, either simultaneous to methionine-rich diet or afterwards, attenuated the above mentioned changes. CONCLUSION: Chronic treatment with danshensu could prevent/attenuate the formation of atherosclerosis. Potential mechanisms include inhibited expression of representative proinflammatory cytokines and adhesion molecules in arterial endothelia. Changes in homocysteine and circulating molecules that control vascular contraction/relaxation via endothelial cells (eg, endothelin and NO) were also implicated.

[The anti-fibrotic effects of Qidan granule in experimental silicosis].

OBJECTIVE: To investigate the anti-fibrotic effects of Qidan granule in rats. METHODS: The rats were randomly divided into six experimental groups: normal group, model group, Qidan group, Tetrandrine group. All rats except normal group were treated with silicon dioxide (50 mg/rat) by intratracheal instillation to induce silicosis. Qidan group and Tetrandrine group were treated with Qidan granule (3125 mg/kg) or treated with Tetrandrine (22 mg/kg) respectively. All the rats were sacrificed after 5 months. Calculate Lung/body coefficient by weighting the lung wet weight and the body weight of rats. Content of Hydroxyproline was measured by alkaline hydrolysis. The gene expression of transforming growth factor-beta1 was examined by using enzyme-linked immunosorbent assay (ELISA). Paraffin embedded lung sections with HE staining, VG staining and Gomori staining were observed under light microscope. RESULTS: In Qidan group and Tetrandrine group, Lung/body coefficient and content of Hydroxyproline and expression of transforming growth factor-beta1 were lower as compared with model group (P < 0.05). Model group mainly showed III approximately IV grade silicotic nodule, which contained thick collagen and sparse reticulum fibe; Qidan group and Tetrandrine group appeared with II grade silicotic nodule, which contained tiny collagen and intensive reticulum fibe. Tetrandrine group showed injury of kidney, and others were normal. CONCLUSION: Qidan granule extract should prevent and from inhibit the remarkably silicotic fibrosis in rats.

[The protective effect of recombinant Chinese interferon-gamma in pulmonary injury in mice].

OBJECTIVE: To observe the protective role of recombinant Chinese interferon-gamma (INF-gamma) in pulmonary injury (PI) induced by bleomycin (BLM) in C57 mice. METHODS: Seventy-five C57 mice were randomly divided into a control group and groups treated with BLM, BLM + INF-gamma minimum dose (0.25 microg/d), BLM + INF-gamma medium dose (0.5 microg/d), and BLM + INF-gamma maximum dose (1.0 microg/d, with 15 mice each). PI was induced by BLM, and intervention with different doses of INF-gamma was carried out in the experiment groups, but no treatment was administered in the control mice. Measurement of pulmonary hydroxyproline (Hyp), image analysis of collagen I and III, and measurement of the ratio between lung alveoli and interstitial areas were performed. RESULTS: Lung Hyp content and collagen I and III deposition were increased as compared with the control after administration of BLM (0.78 +/- 0.08 vs 0.65 +/- 0.06, P < 0.01; 0.048 +/- 0.006 vs 0.004 +/- 0.001, P < 0.01). Hyp content and collagen I and III deposition were reduced in group INF-gamma maximum dose (0.67 +/- 0.08 vs 0.78 +/- 0.08, P < 0.05; 0.008 +/- 0.001 vs 0.048 +/- 0.006, P < 0.01). The ratio of lung collagen to lung tissue areas was increased with the increase of INF-gamma doses (1.78, 0.12, 0.67, 0.73, 1.65 respectively). CONCLUSION: INF-gamma is effective in alleviating BLM induced pulmonary injury in mice, possibly by inhibition of transformation of fibroblasts to myofibroblasts and collagen synthesis.