Abstract
Abstract: :
Purpose: Hypoxia induces deleterious effects on neural cells. Bax–inhibiting peptide (BIP) is a membrane permeable peptide comprised of five amino acids (VPMLK) designed from the Bax–binding domain of Ku70. It inhibits Bax–mediated translocation of cytochrome c and suppresses mitochondria–dependent apoptosis. We evaluate the effects of BIP on hypoxia–induced cell deaths in purified cultured retinal ganglion cells (RGCs). Methods: Purified RGCs were obtained from retina of 6–to 7–day–old rats utilizing the two–step immno–panning procedure and cultured in serum–free medium. After being pre–incubated with VPMLK (10, 50 and 200 µM) for 2 hrs, the RGCs were then incubated under hypoxic condition (5% O2, 5%CO2, 37°C) for 12 hours. Using the calcein–AM assay, the numbers of the viable cells were counted and the cell viabilities were calculated. A scrambled negative control of VPMLK, KLPVM (10, 50 and 200 µM), was also tested. Results: The viability of RGC cultures after 12 hours of hypoxia was 49.0% without BIP treatment. The viability increased in a dose dependent manner with exposure to VPMLK (10 µM: 53.1%; NS, 50 µM: 57.1%; p<0.01, 200 µM: 61.3%; p<0.01, n=8), There was no significant increase of viability in the KLPVM–adding groups. Conclusions:BIP has the protective effect against hypoxia–induced cell death of the purified RGCs. This finding suggests that Bax–mediated apoptosis plays a role in hypoxia–induced damage.
Keywords: neuroprotection • apoptosis/cell death • hypoxia