(a)
(b)
(c)
(d)
(e)
Figure 1: H and E staining of 3D-cultured human oral tissue. Nonirradiated, nontreated oral epithelium (negative control) consists of human oral keratinocytes and is divided into the stratum basalis (basal layer), stratum spinosum (the spindle shaped cell layer), and the stratum corneum (a); irradiated, nontreated tissue (positive control). Keratinocyte injury is noticeable at the top of the tissues, with an increased number of pyknotic cells at the bottom of the tissue (b); irradiated tissue prophylactically treated with NAC shows keratinocyte injury at the top of the tissue (c); irradiated tissue prophylactically treated with QYD shows keratinocyte injury (d); irradiated tissue prophylactically treated with NACQYD shows no injury and resembles the nonirradiated, nontreated negative control tissues (e).