Effect of propofol upon ammonia-induced neocortical astrocyte swelling and aquaporin-4 expression

Abstract

To investigate the effect of propofol upon ammonia-induced neocortical astrocyte swelling and aquaporin-4 expression in rat astrocyte. Methods Astrocytes were isolated from newborn Sprague Dawley rats. After a 3-week culture, cell immunofluorescence was employed to label glial fibrillary acidic protein, the specific protein of astrocyte. Astrocytes were cultured with NH4Cl (5 mmol/L) for 6, 12, 24 and 48h. Astrocytes were pretreated by propofol and DMSO respectively for 30 min and then exposed to NH4Cl for 24h. The expression of AQP4 was detected by the Western blot; cell morphology assessed by light microscopy and cell viability measured by MTF reduction assay. The expression of AQP4 was elevated after a 12h exposure to ammonia, lasted to 48h and peaked at 24h. Astrocytes were found significantly swelling in the NH4Cl-24h and DMSO pretreated groups as compared with the propofol pretreated group. The over-expression of aquaporin-4 was attenuated by propofol pretreatment and the cell viability of astrocytes in the propofol pretreated group was higher than that in the NH4Cl-24h group (P < 0.05). Pretreatment of astrocytes with propofol can inhibit the over-expression of AQP4, relieve cellular swelling and reduce the ammonia-induced decline in cell viability of astrocytes.