Effect of sevoflurane on activities of Na+ -K+ -ATPase and Ca2+ -ATPase in hippocampus of diabetic rats

Abstract

Objective To evaluate the effect of sevoflurane on activities of Na+ -K+ -ATPase and Ca2+ -ATPase in the hippocampus of diabetic rats. Methods SPF healthy male Wistar rats, aged 8 weeks, weighing 180-200 g, were fed a high-fat diet for 3 consecutive weeks and streptozotocin was intraperitoneally injected to induce type 2 diabetes mellitus.Forty-four rats with diabetes mellitus were divided into 2 groups(n=22 each)using a random number table: diabetic group(D group)and sevoflurane group(S group). Another 22 healthy Wistar rats, aged 8 weeks, weighing 180-200 g, served as control group (C group). Oxygen was inhaled for 2 h in C and D groups, and 2.4% sevoflurane was inhaled for 2 h in S group.Eight rats were sacrificed at 30 min after treatment, brains were removed and hippocampi were isolated for measurement of Na+ -K+ -ATPase and Ca2+ -ATPase activities in hippocampal tissues by spectrophotometry.Ten rats were randomly selected at 1 day after treatment, and Morris water maze test was performed to assess the cognitive function.Four rats were randomly sacrificed, brains were removed and hippocampi were isolated for examination of the mitochondrial ultrastructure with a transmission electron microscope. Results Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the percentage of time of staying at the original platform quadrant was decreased, the activities of Na+ -K+ -ATPase and Ca2+ -ATPase in hippocampi were decreased (P<0.05), and mitochondrial swelling and decreased mitochondrial cristae were observed under the electron microscope in group D. Compared with group D, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the percentage of time of staying at the original platform quadrant was decreased, the activities of Na+ -K+ -ATPase and Ca2+ -ATPase in hippocampi were decreased (P<0.05), and mitochondrial swelling and vacuolization were found under the electron microscope in group S. Conclusion The mechanism by which sevoflurane aggravates cognitive dysfunction is related to deceasing activities of Na+ -K+ -ATPase and Ca2+ -ATPase in the hippocampus of diabetic rats. Key words: Anesthetics, inhalation; Cognition; Hippocampus; Sodium-potassium-exchanging ATPase; Calcium-transporting ATPase; Type 2 diabetes mellitus