In situ immunohistochemical study of Bcl-2 and heat shock proteins in human corneal endothelial cells during corneal storage.

AIM: To investigate the expression of Bcl-2 and heat shock proteins (HSPs), which are known to increase cell survival, in human corneal endothelial cells (HCECs) of corneas stored in organ culture.

METHODS: 32 paired corneas were randomly assigned to either a short or a long storage time. The flat mounts of endothelium were examined after immunostaining with monoclonal antibodies to Bcl-2 and HSP 27, 60, 70, and 90.

RESULTS: HCECs expressed generally all the proteins studied. Bcl-2 expression was weaker in the long stored corneas (p=0.035). There was no relation between immunostaining, age, sex, or death to culture time. Frequently some Descemet membranes carried negative cells preferentially located in folds and exhibiting morphological changes consistent with swelling cells corresponding to early stages of apoptosis.

CONCLUSION: Expression of these cytoprotective proteins reflects the high level of HCEC resistance to stresses induced by organ culture. The decreased immunostaining of Bcl-2 in the long storage group could act in cellular loss currently observed with storage time. The negativity of Bcl-2 and HSP labelling in corneal folding may be related to apoptosis.