Lactate Dehydrogenase Assay

Lactate Dehydrogenase (LDH) assay was performed with the Pierce™ LDH Cytotoxicity Assay Kit (Thermo Fisher Scientific, Waltham, MA, USA). After completing the PCLS generation, supernatant of PCLS was harvested in 24 h-intervals over 2 days and replaced with fresh 500 µl DMEM/F12 supplemented with 1% Penicillin-Streptomycin between two 24-h intervals. As positive control for LDH release, PCLS were treated with 1% TritonX-100 at 37°C, 5% CO₂, and 95% humidity for 45 min. The LDH assay was performed immediately after harvesting the supernatant according to the manufacturer’s instructions. The absorbance was measured at 492 nm and at a reference wavelength of 620 nm with the TECAN SUNRISE Absorbance reader (Tecan, Salzburg, Austria) and the Magellan V 5.0 software (Tecan, Salzburg, Austria).