Protective Effects of N-Acetylcysteine on Lipopolysaccharide-Induced Respiratory Inflammation and Oxidative Stress.

As the leading cause of bovine respiratory disease (BRD), bacterial pneumonia can result in tremendous losses in the herd farming industry worldwide. N-acetylcysteine (NAC), an acetylated precursor of the amino acid L-cysteine, has been reported to have anti-inflammatory and antioxidant properties. To explore the protective effect and underlying mechanisms of NAC in ALI, we investigated its role in lipopolysaccharide (LPS)-induced bovine embryo tracheal cells (EBTr) and mouse lung injury models. We found that NAC pretreatment attenuated LPS-induced inflammation in EBTr and mouse models. Moreover, LPS suppressed the expression of oxidative-related factors in EBTr and promoted gene expression and the secretion of inflammatory cytokines. Conversely, the pretreatment of NAC alleviated the secretion of inflammatory cytokines and decreased their mRNA levels, maintaining stable levels of antioxidative gene expression. In vivo, NAC helped LPS-induced inflammatory responses and lung injury in ALI mice. The relative protein concentration, total cells, and percentage of neutrophils in BALF; the level of secretion of IL-6, IL-8, TNF-α, and IL-1ß; MPO activity; lung injury score; and the expression level of inflammatory-related genes were decreased significantly in the NAC group compared with the LPS group. NAC also ameliorated LPS-induced mRNA level changes in antioxidative genes. In conclusion, our findings suggest that NAC affects the inflammatory and oxidative response, alleviating LPS-induced EBTr inflammation and mouse lung injury, which offers a natural therapeutic strategy for BRD.

Rho/Rho-associated protein kinase signaling pathway-mediated downregulation of runt-related transcription factor 2 expression promotes the differentiation of dental pulp stem cells into odontoblasts.

The present study investigated the role of runt-related transcription factor 2 (Runx2) in regulating the differentiation of human dental pulp stem cells (hDPSCs) into odontoblasts under the mediation of the Rho/Rho-associated protein kinase (ROCK) signaling pathway. hDPSCs and human bone marrow mesenchymal stem cells (hBMSCs) were mineralized to induce differentiation. The expression levels of odontoblast- and osteoblast-specific proteins, dentin sialophosphoprotein (DSPP), osteocalcin (OCN) and Runx2, were measured using western blot analysis. The hDPSCs were treated with Rho/ROCK signaling pathway inhibitor, C3 exoenzyme, and mineralized prior to determining the protein expression levels of RhoA, ROCK, Runx2, OCN, DSPP, and mRNA expression levels of early mineralization genes, including alkaline phosphatase, collagen type I, Msh homeobox 2 and distal-less homeobox 2, and late mineralization genes, including DSPP, dentin matrix protein-1 (DMP-1), bone sialoprotein (BSP) and OCN. Flow cytometry data indicated that 95% of the isolated hDPSCs were positive for mesenchymal stem cell markers, including cluster of differentiation (CD)29, CD90 or CD105, and vascular endothelial cell marker, CD146, whereas <5% of the hDPSCs were positive for hematopoietic stem cell markers, CD34 and CD45. The expression levels of DSPP in hDPSCs and OCN in hBMSCs were significantly upregulated with increased time in mineralization medium (P<0.01), which suggested that hDPSCs and hBMSCs were differentiated into odontoblasts and osteoblasts, respectively. During the osteogenic process, Runx2 protein was highly expressed in mesenchymal stem cells following stimulation with mineralization medium compared with cells that received no stimulation. During odontoblast differentiation in hDPSCs, Runx2 protein was highly expressed in the early stage; however, the expression declined in the late stage. Furthermore, treatment with C3 exoenzyme significantly downregulated the expression of RhoA, ROCK and Runx2 compared with the control in hDPSCs (P<0.01). Additionally, in mineralization solution, C3 exoenzyme also significantly downregulated the expression of Runx2 (P<0.01); however, the Rho/ROCK signaling pathway inhibitor did not significantly impact the expression of early mineralization genes. By contrast, C3 exoenzyme significantly upregulated the expression of DSPP and DMP-1, and downregulated the expression of BSP and OCN (P<0.01). The present findings suggested that odontoblast differentiation in hDPSCs may be regulated by Rho/ROCK signaling pathway-mediated downregulation of Runx2.

[The influence of Qi-lan granulates on the variation of proliferating cell nuclear antigen during the course of SD rat tongue carcinogenesis].

PURPOSE: To study the cancer blocking effect of the Qi-lan granulates in SD rats. METHODS: A total of 150 SD rats were divided into five groups A,B,C,D,E. Rats in group A, B, C, D were fed with 0.002% 4NQO dissolved in drinking water to induce tongue carcinogenesis in rats. Different concentration of the herb Qi-lan granulates was given to the rats of group B, C, D during oral carcinogenesis. Group A was model group, group E was normal group. The rats were sacrificed at 9, 18, 27 and 36 weeks respectively from the beginning of the experiment. The samples were collected for histophology and PCNA immunohistochemistry. The date was analyzed by Chi-square test and Kruskal-Wallis test using SPSS13.0 software package. RESULTS: The overall canceration rate of group B (14.29%), C (3.57%), D (14.29%) was significantly lower than group A (39.29%) (P<0.05), the effect of Qi-lan granulates in group C was the best. Immunohistochemistry result showed that 6 cases of normal oral mucosa in group A had positive expression of PCNA. In 11 cases of dysplasia, 8 had positive express of PCNA, 11 rats with oral cancerous tissues had positive expression of PCNA.In group A, the expression of PCNA was normal tissue0.05). In general, the expression of PCNA in group A was significantly higher than the Qi-lan granulates group, the difference was statistically significant (P<0.05). The expression of PCNA in group E was negative. CONCLUSIONS: Qi-lan granulates have significant inhibitory effect on tongue cancer, through blocking cell proliferation.

[Significance of cell immunoreactions and cell apoptosis in oral lichen planus].

OBJECTIVE: To evaluate the expression of CD4+, CD8+ T cells and cell apoptosis in oral lichen planus (OLP) and investigate the role and the relationship of immunological reaction and cell apoptosis in the pathogenesis of OLP2. METHODS: Immunohistochemical technique was used to study the expression of CD4+, CD8+ T cells in 27 OLP cases. TUNEL was used for detecting the cell apoptotic index (AI) in 17 OLP2 cases. RESULTS: The expression of CD4+, CD8+ T cells were obviously elevated in lamina propria of OLP group compared with control group (P<0.05). There was a strong significance when compared the ration of CD4/CD8 in both group. AI was remarkably increased in epithelia cells and significantly decreased in lymphocytes in lamina propria in OLP cases compared with its expression in the control group respectively. CONCLUSION: The increased amount of CD4+, CD8+ T cells in lamina propria of OLP and the change ration of CD4/CD8 suggest that immune response is involved in the pathogenesis of OLP. The abnormal cell apoptosis plays an important role in the pathogenesis of OLP.

[Expression of TGF-beta1, Smad7 and cell apoptosis in epithelium of oral lichen planus].

OBJECTIVE: To examine the expression of TGF-beta1, Smad7 and cell apoptosis in oral lichen planus (OLP) and to evaluate the possible pathogenesis of oral lichen planus. METHODS: Immunohistochemical technique was used to study the expression of TGF-beta1 and Smad7 in the epithelia cells of 17 OLP cases and 7 normal oral mucosa (NOM). TUNEL was used for detecting the cell apoptosis in 17 OLP cases and 7 NOM. RESULTS: TGF-beta1 was moderately positive in the epithelia cells of OLP. All the epithelia cells in OLP showed strong cytoplasmic staining. The expression of TGF-beta1 and Smad7 were significantly increased in OLP compared with that in NOM (P < 0.05). Cell apoptotic index (AI) was remarkably increased in epithelia cells in OLP cases, and the cell apoptosis was localized in basal and suprabasal epithelial layers. There was a positive correlation between TGF-beta1 expression and cell apoptosis in the epithelia of OLP (r = 0.69, P <0.05). CONCLUSIONS: High expression of TGF-beta1 and Smad7 in the epithelia of OLP suggests that TGF-beta1-Smad7 signal pathway was disturbed in oral lichen planus. The imbalance of TGF-beta1-Smad7 pathway may contribute to the mechanisms of cell apoptosis of epithelial cells in OLP.