Uv light meter

Before UVA irradiation, HDFs cells were rinsed and submerged under a thin layer of PBS to prevent UVA absorption by components of the medium, such as VB1. Cells were then irradiated using a Philips UVA lamp with an emission spectrum between 320 and 400 nm. Mock-irradiated cells were manipulated identically, except that they were not exposed to UVA. The dose of UVA irradiation was 10 J/cm² per day, as verified with a UV light meter (Sigma, Shanghai, China) for 3 days. Following each UVA irradiation, cells were incubated in complete medium, supplemented with indicated compounds.

To prevent UVA absorption by factors within the growth medium, when reached 80% confluence, HDF cells were rinsed in phosphate-buffered saline (PBS), and submerged under a thin layer of PBS prior to UVA irradiation. Cells were then irradiated three times with a UVA dose of 10 J/cm² per day for 3 days, as verified with a UV light meter (Sigma, Shanghai, China), using a Philips UVA lamp (emission spectrum320 to 400 nm). Mock-irradiated cells underwent identical procedures, but were not exposed to UVA. The time interval of these three UVA irradiations is 24 hours. Following each UVA irradiation, cells were incubated in complete medium as described above.