Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, Chiang Mai University, Chiang Mai, 50200, Thailand.
Department of Family and Community Dentistry, Chiang Mai University, Chiang Mai, Thailand.
Clin Oral Investig. 2021 Jun;25(6):3919-3928. doi: 10.1007/s00784-020-03721-7. Epub 2021 Jan 6.
N-Acetyl cysteine (NAC), a well-known antioxidant molecule, has been used to modulate oxidative stress and inflammation. However, no studies have examined the effect of NAC in regenerative endodontic procedures (REPs). Therefore, the aim of this study was to investigate the effects of NAC on cell survival, mitochondrial reactive oxygen species (mtROS) production, and inflammatory and mitochondria-related gene expression on lipopolysaccharide (LPS)-treated apical papilla cells (APCs).
To assess the NAC concentration, 5 and 10 mM NAC were administered to LPS-treated APCs. Cell proliferation was measured at 24, 48, and 72 h by using AlamarBlue® assay. The 5-mM concentration was further analyzed using different treatment durations: 10 min, 24 h, and the entire study period. The mtROS production was quantified using MitoSOX™ Red and MitoTracker™ Green. RT-PCR was used to detect the expression of IL-6 and TNF-α inflammatory genes and mitochondrial morphology-related genes (Mfn-2/Drp-1 and Bcl-2/Bax) at 6 and 24 h. The statistical significance level was set at 0.05.
Five-millimolar NAC promoted the highest LPS-treated APC proliferation. The use of 24-h NAC stimulated cell proliferation, whereas the entire-period NAC application (> 48 h) significantly reduced the cell number. The mtROS levels were slightly altered after NAC induction. Ten-minute NAC treatment downregulated the IL-6 and TNF-α expression, whereas the expression of Bcl-2/Bax and Mfn-2/Drp-1 ratios was upregulated at 6 h.
Under the LPS-induced inflammatory condition, NAC stimulated APC survival and decreased inflammation. Ten-minute NAC treatment was sufficient to reduce the level of inflammation and maintain the mitochondrial dynamics.
Ten-minute NAC application is sufficient to reduce the level of inflammation and maintain the mitochondrial dynamics. Therefore, NAC may be considered as a potential adjunctive irrigation solution in REPs.
N-乙酰半胱氨酸（NAC）是一种众所周知的抗氧化分子，已被用于调节氧化应激和炎症。然而，尚无研究探讨 NAC 在再生性牙髓治疗（REP）中的作用。因此，本研究旨在探讨 NAC 对脂多糖（LPS）处理的根尖乳头细胞（APC）的细胞存活、线粒体活性氧（mtROS）产生以及炎症和线粒体相关基因表达的影响。
为了评估 NAC 的浓度，将 5 和 10mM 的 NAC 给予 LPS 处理的 APC。通过使用 AlamarBlue® 测定法在 24、48 和 72 小时测量细胞增殖。进一步分析 5mM 的浓度，采用不同的处理时间：10 分钟、24 小时和整个研究期间。使用 MitoSOX™ Red 和 MitoTracker™ Green 定量测定 mtROS 的产生。使用 RT-PCR 在 6 和 24 小时检测 IL-6 和 TNF-α 炎症基因以及线粒体形态相关基因（Mfn-2/Drp-1 和 Bcl-2/Bax）的表达。统计显著性水平设置为 0.05。
5mM 的 NAC 促进 LPS 处理的 APC 增殖率最高。24 小时的 NAC 应用刺激细胞增殖，而整个时间段（>48 小时）的 NAC 应用显著减少细胞数量。NAC 诱导后 mtROS 水平略有改变。10 分钟的 NAC 处理下调了 IL-6 和 TNF-α 的表达，而 Bcl-2/Bax 和 Mfn-2/Drp-1 比值的表达在 6 小时时上调。
在 LPS 诱导的炎症条件下，NAC 刺激 APC 存活并减少炎症。10 分钟的 NAC 处理足以降低炎症水平并维持线粒体动力学。
10 分钟的 NAC 应用足以降低炎症水平并维持线粒体动力学。因此，NAC 可能被认为是 REP 的潜在附加冲洗液。
