Table 1.

Qualitative, semi-quantitative scoring system used to evaluate the tissue integrity and viability of the ovine skin explants from the 3D culture model.

Score	Histopathology (changes observed)	Tissue viability
0 (plus signs stated below)	- Acute ischaemic degeneration of epidermal cells (necrosis) - Severe extent of all epidermal and dermal changes described below	Tissue is not viable
1 Marked (plus signs stated below)	- Multifocal subepidermal clefting - Basal cell vacuolisation (epidermal degeneration) - Nuclear pyknosis and detachment of eccrine glands, leukocytes and epidermal cells showing signs of autolysis - Multifocal pyknosis of basal cells with degenerating neutrophils	Tissue is viable
1.5 Moderate to marked (plus signs stated below)	- Apoptotic keratinocytes - Vacuolation of basal cells - Supepidermal clefting - Eccrine glands and peripheral nerves show signs of autolysis, as do some follicular epithelial cells (detached)	Tissue is viable
2 Moderate (plus signs stated below)	- Prominent pyknotic nuclei in stratum spinosum - Some subasilar clefting around follicles - Few sloughed epithelial cells in glands	Tissue is viable
2.5 Mild to moderate (plus signs stated below)	- Scattered apoptotic keratinocytes	Tissue is viable
3 Mild	- Normal tissue architecture and viability and occasionally few sloughed epithelial cells within eccrine glands	Tissue is viable