LncRNA A2M-AS1 lessens the injury of cardiomyocytes caused by hypoxia and reoxygenation via regulating IL1R2.

BACKGROUND: Myocardial ischemia and reperfusion injury (MI/RI) is a complex pathophysiological process, which can lead to severe myocardial injury. The long noncoding RNA alpha-2-macroglobulin antisense RNA 1 (A2M-AS1) has been revealed to be abnormally expressed in MI, However, its function in MI and the potential mechanism are still unclear. OBJECTIVE: To evaluate the functional role of A2M-AS1 in hypoxia/reoxygenation (H/R)-induced neonatal cardiomyocytes and its potential molecular mechanism. METHODS: Dataset GSE66360 was obtained from GEO database for analyzing the RNA expression of A2M-AS1 and interleukin 1 receptor type 2 (IL1R2). KEGG pathway enrichment analysis of the genes that co-expressed with A2M-AS1 was performed. Human neonatal cardiomyocytes were subjected to H/R to construct in vitro models. QRT-PCR and Western blot were adopted to test the levels of mRNA and protein. The viability and apoptosis of cardiomyocytes were tested by CCK-8 and flow cytometry assays, respectively. RESULTS: The expression of A2M-AS1 was notably downregulated in H/R-treated cardiomyocytes. Overexpression of A2M-AS1 can notably enhance the cell viability of H/R-damaged cardiomyocytes, whereas knockdown of A2M-AS1 showed the opposite outcomes. Besides, a negative correlation was showed between A2M-AS1 and IL1R2 expression. In H/R-treated cardiomyocytes, overexpression of IL1R2 weakened the promoting proliferation and anti-apoptosis effects caused by overexpressing A2M-AS1, however, IL1R2-knockdown abolished the anti-proliferation and pro-apoptosis effects caused by silencing A2M-AS1. CONCLUSION: This study demonstrates the potential regulatory role of A2M-AS1/ IL1R2 axis in cardiomyocytes suffered from H/R, and provides insight into the protection of MI/RI.

[An in vitro evaluation of the effect of carboxymethyl chitosan and its composites against Enterococcus faecalis in the root canal].

PURPOSE: To evaluate the bacteriostasis effect of carboxymethyl chitosan and its composites on intracanal E. faecalis. METHODS: The pattern of E. faecalis infecting root canal was established, and then divided into 4 groups(A, B, C and D).They were filled with 2% chlorhexidine solution, 140 mg/mL mixture of carboxymethyl chitosan and chlorhexidine solution, 5 mg/mL carboxymethyl chitosan solution and calcium hydroxide paste respectively and incubated for 7 days. Samples obtained before and after the intracanal medication were plated onto BHI media to determine the colony-forming units (CFU/mL) after 48 hours. The data were analysed using SPSS 13.0 software package. RESULTS: Before intracanal medication, the variance of bacterial counts were not significantly different (P>0.05). After medication, the four groups showed significant difference in bacterial counts immediately(P<0.05).The antimicrobial effects of A and B group were better than group C and D. CONCLUSIONS: The antibiotic activity of 2% chlorhexidine solution and 140 mg/L mixture of carboxymethyl chitosan and chlorhexidine solution to E.faecalis were better. Supported by Key Science and Technology Project of Liaoning Province(2010225001).

[Study of the effect of chitosan and its composites on proliferation and differentiation of mouse osteoblasts].

PURPOSE: A mouse osteoblast cell line, MC3T3-E1, was cultivated in the medium that contained chitosan, type I collagen and recombinant human bone morphogenetic protein-2 in vitro to evaluate the effect of chitosan and its composites on proliferation and differentiation of mouse osteoblasts. METHODS: This study was categorized into 4 groups based on the medium used. Group A: α-MEM medium; group B: CS, type I collagen and α-MEM medium; group C: CS, type I collagen, rhBMP-2 and α-MEM medium. α-MEM medium containing 1%FBS was used in the control group. Cells of each group were cultivated for 1,3,5 and 7 days. The optical density (OD) value at each time point was evaluated with MTT assay and growth curve was drawn to observe the proliferation of osteoblasts. Differentiation of osteoblasts was determined with alkaline phosphatase (ALP) activity assay, alkaline phosphatase staining and alizarin red staining. Alkaline phosphatase activity of each group was measured at day 1, 3, 5 and 7 days. After 7 days of culture, the cells were stained with alkaline phosphatase, and at day 14, the mineralized nodules were stained with alizarin red. Statistical analysis was performed using SPSS13.0 software package. RESULTS: The MTT assay results showed that the OD value was maximal when osteoblasts were cultured in group C. The difference were statistically significant between group C and others (P<0.05). The ALP activity showed that the result of group C was significantly higher than other groups. The increase of ALP activity was significant between group C and control group (P<0.05). However, no significant difference was found between group C and group B (P>0.05). Compared with the control group, group C had more calcium nodules and blue particles than others. CONCLUSIONS: The incorporation of type I collagen and bone morphogenetic protein-2 into chitosan can promote MC3T3-E1 cell proliferation and differentiation better. Supported by Major Science and Technology Project of Liaoning Province (2010225001).