Naocl

The root canal was prepared using MTWO files (VDW, Munich, Germany) adapted to an electric motor (VDW Silver motor; VDW) in rotary movement. The following files were used: size #10/0.04, #15/0.05, #20/0.06 and #25/0.06. The instrumentation was performed in a gentle in-and-out motion, taking the files to the working length.
During instrumentation, the canals were irrigated using 1 mL of distilled water following the use of each instrument. After the instrumentation was completed, the debris in the root canal was subjected to ultrasonic vibration. Then, the root canal opening was dried and sealed with flowing resin (Beautiful Flow Plus F00, Shofu, Japan).
The three groups were subdivided into four subgroups (n = 40) based on the irrigation solution used: subgroup A, distilled water; subgroup B, 1% NaOCl (Sigma-Aldrich Co., USA); subgroup C, 2% NaOCl (Sigma-Aldrich Co.); subgroup D, 5.25% NaOCl (Sigma-Aldrich Co.). Half of the samples in each subgroup were washed with CNI, and half were washed with PIPS (n = 20).

Exponential phase cells were used for toxicant treatments. Typical toxicants CuSO₄ (Cat. number C1297, Sigma, MO), NaOCl (Cat. number 425044, Sigma, MO), and Aroclor 1016 (48701, Sigma, a type of PCBs) were employed in the present study. To test the doses effect of toxicants on CpHSP70 and CpHSP90 transcriptional expression, a series of concentrations of each toxicant were added in the C. polykrikoides cultures (with final concentration of CuSO₄: 1, 5, and 8 mg L⁻¹; NaClO₃: 0.02, 0.1, 0.3, and 0.5 mg L⁻¹; PCB: 0.05, 0.1, 0.2, and 0.5 mg L⁻¹). The treated and untreated cultures were harvested for gene expression analysis at indicated time points. RNA extraction and cDNA were prepared with the same manner described previously. Gene expression and statistical analysis were followed by Guo et al. [27 (link)].

Commercial chow diet (balanced diet), containing 67% carbohydrates, 10% fat, and 23% protein as the energy sources (overall calories: 3.6 kcal/g), was purchased from El Gomhorya company (Cairo, Egypt). Azathioprine (AZA): manufactured by EXCELLA Gmbh & Co. Feucht, Germany. Taurine (TAU): 2-amino ethane sulfonic acid was supplied by GALL Pharma, Austria Pharmaceutical. Taurine-chloramine (TAU-Cl), N-Monochlorotaurine, was synthesized freshly on the day of use by adding equimolar amounts of NaOCl (Sigma-Aldrich) to taurine. This was prepared by dropwise additions of 5 ml of 2 mM NaOC1 (Sigma) solution in 0.06 M phosphate buffer (pH 7.4-7.5) with vigorous stirring to 5 ml of 29 mM amine solution in the same buffer. The authenticity of TAU-Cl formation was monitored by UV absorption (200–400 nm). Its sodium salt form (molecular weight 181.57) was prepared, and its purity was checked according to a previously published method of Gottardi and Nagl (2002) [14 (link)]. Stock solution of taurine chloramine was kept at 4 ºC for a maximum period of 2 weeks before use.