“…Overall, the majority of in vitro studies used fibroblastic skin cells. Human dermal fibroblasts (HDFs) were commonly used [ 20 , 21 , 22 , 24 , 27 , 28 , 31 , 34 , 35 , 36 ], followed by T3T mouse fibroblasts [ 19 , 23 , 25 , 29 , 30 ], and L929 mouse fibroblasts [ 33 , 35 ]. However, human epidermal keratinocytes (HEKs) were also used in four studies [ 22 , 31 , 34 , 35 ].…”