Reaction solution

After IPL treatment, the T. rubrum suspension was incubated with 100 μl NOS detection buffer and 100 μl reaction solution (Beyotime Biotechnology, Haimen, China) at 28°C for 30 min and washed in PBS twice. The fluorescent signal intensity was analyzed using a flow cytometer (BD FACS Canto II) at an excitation wavelength of 495 nm and an emission wavelength of 515 nm.

We used a fluorescent probe method to detect the level of NOS activity. This method uses a nitric oxide fluorescent probe (DAF-FM DA) to detect the amount of nitric oxide that can be produced by NOS in a cell by providing sufficient substrates. Thereby, the activity of NOS was detected. After coculture with HaCaT cells, the T. rubrum suspension was incubated with 100 μl of NOS detection buffer and 100 μl of reaction solution (Beyotime Biotechnology, Haimen, China) at 37°C for 20-60 min in a CO₂ incubator. The fluorescence signal intensity was analyzed using a flow cytometer (BD FACSCanto II) at an excitation wavelength of 495 nm and an emission wavelength of 515 nm. Based on the fluorescence signal intensity, we could detect the level of NOS activity in T. rubrum.