Effects of isoflurance on learning and memory function and receptor for advanced glycation end products expression of hippocampus in rats

Abstract

Objective To explore the effect of isofluranee on receptor for advanced glycation end products (RAGE) expression of hippocampus and learning and memory function in rats. Methods 24-month Sprague-Dawley male rats (n=45) and 4-month Sprague-Dawley male rats (n=45) were randomly divided into six groups with 15 rats each group. Group C1 (aged control group),group C2(adult control group) breath 30% oxygen and air mixed gas; Group S1(single inhalation of isoflurane aged group),Group S2(single inhalation of isoflurane adult group)were anesthetized with 1.5% isoflurane,breath 30% oxygen and air mixed gas for 2h;Group R1(Repeated inhalation of isoflurane aged group), group R2(Repeated inhalation of isoflurane adult group) were anesthetized with 1.5% isoflurane,breath 30% oxygen and air mixed gas 2h a day for three days. Eight rats randomly selected from each group were killed and their hippocampus were immediately isolated for detection of RAGE expression by immunohistochemistry and RT-PCR after accomplished treatment 24h. The remained rats' learning and memory function were assessed using Morris water-maze test. Results The results of Morris water-maze test showed that the times of acerossing the original platform and the time consumption of staying the original platform quadrant was shorter in group S1 and group R1,but the escape latency was longer than group C1(escape latency C1 (9.42± 2.63)s,S1(13.20±3.85)s,R1(17.20±3.44)s, F=12.773, P 0.05). The levels of mRNA and protein of RAGE in hippocampus was significantly higher in group S1 and group R1 than group C1(RAGE mRNA expression C1(0.11±0.02),S1 (0.56±0.09), R1(0.73±0.14), F=179.447, P 0.05), but it was higher in the group R2 (RAGE mRNA express C2(0.22±0.04), R2 (0.41±0.08), F=40. 209, P < 0. 01). Conclusion Isoflurane can reduce learning and memory function in both aged and adult rats, but aged rats are particularly significant im-pacted. This effect may be induced by the increase of RAGE expression in hippocampas. Key words: Isoflurance; Cognition; Receptors; Advanced glycation end products; Hippocampus