Pathomorphological peculiarities of damage to hair cells of the organ of Corti in experimental sensorineural hearing loss

Pathomorphology of the organ of Corti was studied on models of acute and chronic sensorineural damage to the acoustic analyzer. Peculiarities of hair cell degeneration, necrosis, and apoptosis in the organ were studied by light and scanning electron microscopy. The type of pathomorphological substrate in abnormalities of the organ of Corti depends on the intensity of the destructive exposure, but not on the nature of otopathological factors. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 3, pp. 356–360, March, 2006     

Relationship between stiffness,internal cell pressure and shape of outer hair cells isolated from the guinea-pig hearing organ

The mechanical properties of outer hair cells are of importance for normal hearing, and it has been shown that damage of the cells can lead to a reduction in the hearing sensitivity. In this study, we measured the stiffness of isolated outer hair cells in hyper- and hypotonic conditions, and examined the change in stiffness in relation to the corresponding changes in internal cell pressure and cell shape. The results showed that the axial stiffness of isolated outer hair cells (30–90 μm in length, 8–12 μm in diameter), ranging from 0.13–5.39 mN m^?1, was inversely related to cell length. Exposure to hyper- and hypotonic external media with a small percentage change in osmolality caused a similar magnitude of change in cell length and cell diameter, but an average 60% change in cell stiffness. Therefore, a moderate osmotic change in the external medium can lead to a significant alteration in cell stiffness. The findings thus indicate an important contribution of internal cell pressure to cell stiffness.     

脂多糖通过核因子-κB途径影响腹膜间皮细胞生长及TNF的表达

目的研究脂多糖(LPS)是否通过核因子κB,即IκBα、NF-κBp65途径引起腹膜间皮细胞(peritonealmesothelial cells,PMC)凋亡、抑制细胞生长和诱导肿瘤坏死因子(TNF)的表达。方法胰蛋白酶-EDTA消化法用于PMC的原代培养、传代,经鉴定分组①不同浓度LPS组(正常对照组、0.1mg/L、1.0mg/L、10mg/L、50mg/L、100mg/L);②不同时间组LPS作用于PMC0、1、3、6、12、24h。Hoechst33258染色法检测PMC的凋亡;MTT法检测PMC的生长增殖抑制情况;免疫荧光法检测p65的活性;Western blot检测IκBα的表达;用L929细胞株检测TNF的活性;RT-PCR检测TNFα mRNA的表达。结果LPS抑制PMC生长并诱导凋亡、引起IκBα的降解、p65的核移位;LPS诱导PMC表达TNF,1hTNF-α mRNA达最大值、3hTNF-α活性达最大值。结论LPS可抑制PMC的生长及诱导凋亡;LPS诱导PMC表达TNF-α呈浓度依赖性,在LPS作用早期TNF-α明显升高,随后下降。这一过程中IκBα-NF-κBp65信号途径可能发挥了重要作用。     

MicroRNA-301b-3p accelerates the growth of gastric cancer cells by targeting zinc finger and BTB domain containing 4

MicroRNAs (miRNAs) have been found to be aberrantly expressed and exert essential roles in the tumorigenesis and progression of gastric cancer (GC). miR-301b-3p has been recognized as a cancer-related miRNA in lung cancer, bladder cancer and hepatocellular carcinoma. However, the function of miR-301b-3p in GC progression and its underlying mechanism have not been studied yet. In this study, we found that miR-301b-3p expression was up-regulated in GC tissues compared to adjacent noncancerous tissues. Furthermore, the elevated levels of miR-301b-3p were detected in GC cell lines (SGC-7901, AGS, MKN-45 and MGC-803) as compared with GES-1 cells. Interestingly, GC tissues from patients with tumor size ≥ 5 cm and advanced tumor stages showed obvious higher levels of miR-301b-3p compared to matched controls. Functionally, miR-301b-3p knockdown prominently inhibited cell proliferation, and induced cell cycle arrest at G1 phase and apoptosis in MGC-803 cells. Meanwhile, ectopic expression of miR-301b-3p conversely regulated these biological behaviors of MKN-45 cells. Next, we found that miR-301b-3p knockdown increased, whereas miR-301b-3p overexpression reduced the expression of zinc finger and BTB domain containing 4 (ZBTB4) in GC cells. Accordingly, luciferase reporter assay identified ZBTB4 as a direct target of miR-301b-3p. ZBTB4 overexpression markedly restrained the growth of MGC-803 cells. More importantly, ZBTB4 silencing partially reversed miR-301b-3p knockdown-induced tumor suppressive effects on MGC-803 cells. In conclusion, we firstly revealed that miR-301-3p was highly expressed in GC and contributed to tumor progression via attenuating ZBTB4, which might provide a novel molecular-targeted strategy for GC treatment.