Pressure related apoptosis in neuronal cell lines

Pressure is a crucial component of the cellular environment, and can lead t o pathology if it varies beyond its normal range, The increased intra-ocula r pressures in acute glaucoma are associated with the loss of neurons by ap optosis. Little is known regarding the interaction between pressure and apo ptosis at the level of the cell, The model developed in this study examines the effects of elevated ambient hydrostatic pressure directly upon culture d neuronal lines. Conditions were selected to be within physiological limit s: 100 mmHg over and above atmospheric pressure for a period of 2 hr, as se en clinically in acute glaucoma. This system can be used to investigate pre ssure relatively independently of other variables. Neuronal cell line cultu res (B35 and PC12) were subjected to pressure conditions in specially desig ned pressure chambers. Controls were treated identically, except for the ap plication of pressure, and positive controls were treated with a known apop totic stimulus, Apoptosis was detected by cell morphology changes and by 2 specific apoptotic markers: TUNEL (Terminal transferase dUTP Nick-End Label ing) and Annexin V. These fluorescent markers were detected and quantified by automated Laser Scanning Cytometry, All techniques showed that increased pressure was associated with a greater level of apoptosis compared to equi valent controls. Our results suggest that pressure alone may act as a stimu lus for apoptosis in neuronal cell cultures. This raises the possibility of a more direct relationship at the cellular level between pressure and neur onal loss. (C) 2000 Wiley-Liss, Inc.