RESUMO
In the present study, the effects of tubeimoside I (TBMS1) on particulate matter <2.5 µm in diameter (PM2.5)-induced pulmonary injury and its mechanisms of action were investigated. Male BALB/c mice were randomly assigned into five groups (n=10/group): Control, PM2.5, PM2.5 + TBMS1 45 mg/kg, PM2.5 + TBMS1 90 mg/kg and PM2.5 + TBMS1 180 mg/kg. The dose of the PM2.5 suspension administered to the mice was 40 mg/kg via nasal instillation. The PM2.5 + TBMS1 groups received TBMS1 daily orally for 21 consecutive days, while the mice in the control and PM2.5 groups received equivalent volumes of PBS. Subsequently, lactic dehydrogenase, acid phosphatase, alkaline phosphatase, albumin, tumor necrosis factor-α and interleukin-6 protein levels in bronchoalveolar lavage fluid were determined. Oxidative stress was evaluated by detecting the protein levels of malondialdehyde, superoxide dismutase and inducible nitric oxide synthase, and the level of nitric oxide in lung tissue. Lastly, histopathological images of lung sections were obtained to observe changes in the lung tissue with treatment. The results indicated that exposure to PM2.5 induced pathological pulmonary changes, and biofilm and parenchymal cell damage, and promoted inflammation and oxidative stress. Treatment with TBMS1 attenuated the development of PM2.5-induced pulmonary injury. Its mechanisms of action were associated with reducing cytotoxic effects, levels of inflammatory mediators and oxidative damage. In conclusion, the results of the present study indicate that TBMS1 is a potential therapeutic drug for treating PM2.5-induced pulmonary injury.
RESUMO
BACKGROUND: Pterygium is a common ocular surface disease characterized by abnormal epithelial and fibrovascular proliferation, invasion, and matrix remodeling. This lesion, which migrates from the periphery to the center of the cornea, impairs vision and causes considerable irritation. The mechanism of pterygium formation remains ambiguous, and current treatment is solely surgical excision, with a significant risk of recurrence after surgery. Here, we investigate the role of methylation in DNA sequences that regulate matrix remodeling and cell adhesion in pterygium formation. METHODOLOGY/PRINCIPAL FINDINGS: Pterygium and uninvolved conjunctiva samples were obtained from the same eye of patients undergoing surgery. The EpiTYPER Sequenom technology, based on differential base cleavage and bisulfite sequencing was used to evaluate the extent of methylation of 29 matrix and adhesion related genes. In pterygium, three CpG sites at -268, -32 and -29 bp upstream of transglutaminase 2 (TGM-2) transcription initiation were significantly hypermethylated (p<0.05), whereas hypomethylation was detected at CpGs +484 and +602 bp downstream of matrix metalloproteinase 2 (MMP-2) transcription start site, and -809, -762, -631 and -629 bp upstream of the CD24 transcription start site. RT-qPCR, western blot and immunofluorescent staining showed that transcript and protein expression were reduced for TGM-2 and increased for MMP-2 and CD24. Inhibition of methylation in cultured conjunctival epithelial cells increased these transcripts. CONCLUSIONS/SIGNIFICANCE: We found regions of aberrant DNA methylation which were consistent with alteration of TGM-2, MMP-2, and CD24 transcript and protein expression, and that inhibition of methylation in cultured cells can increase the expression of these genes. Since these genes were related to cell adhesion and matrix remodeling, dysregulation may lead to fibroblastic and neovascular changes and pterygium formation. These results have implications for the prognostication of pterygium in clinical practice, for example, detection of epigenetic changes may have a role in predicting post surgical recurrence of aggressive lesions.