[Ultrastructural and growth factor analysis of amniotic membrane preserved by different methods for ocular surgery]

To compare the anatomical structure and the presence of growth factors and cytokines of amniotic membrane preserved in glycerol/MEM (1:1) or undiluted dimethyl sulfoxide through electron microscopy.

Amniotic membrane preserved in glycerol/MEM (1:1) or undiluted dimethyl sulfoxide were processed for transmission and scanning electron microscopy. As control, freshly collected amniotic membrane was fixed and processed for electron microscopy. The cytokines and growth factors assessed were: TGF-beta (transforming growth factor beta); TGF-beta activ (activated transforming growth factor beta); EGF (epidermal growth factor); FGF-4 (fibroblast growth factor 4); bFGF (basic fibroblast growth factor); IL-4 (interleukin 4); PGE2 (prostaglandin E2); IL-10 (interleukin 10); KGF (keratinocyte growth factor); HGF (hepatocyte growth factor).

Amniotic membrane from the control group showed intact epithelium, with surface microvilli and junctional complexes between the cells and the basal membrane. Glycerol/MEM preserved amniotic membrane had similar aspect to the control, with higher epithelial cells. Those amniotic membranes preserved in dimethyl sulfoxide disclosed less intercellular junction and detachment of the epithelium from the basal membrane. The cytokines and growth factors did not disclose significant differences, except for FGF-4, bFGF, PGE2 and KGF.

Amniotic membrane preserved in glycerol/MEM showed a better tissue structure, with less detachment of the epithelium from the basal membrane, in comparison to undiluted dimethyl sulfoxide. The majority of the growth factors and cytokines were kept with both techniques of preservation.