OBJECTIVETo observe changes of learning and memory ability (LMA) in burn rats with depression, and study the relationship between LMA and expression of hippocampal NMDA.

METHODSAccording to simple random method, 46 Wistar rats were divided into burn group (B, with 30% TBSA deep partial-thickness burn, n = 10), depression group (D, with moderate stress stimulation in chronic and unpredictable, n = 12), B + D group (with the same stress stimulation inflicted to B group after burn, n = 12), healthy control group ( HC, without treatment, n = 12). Changes in escape latency was examined in water maze test. Expression of hippocampal NMDA in CA1, CA2 regions and dentate gyrus were observed with immunohistochemistry.

RESULTSCompared with that of HC group (22 +/- 20 s), water maze escape latency in B, D, B + D groups on 2 day after training prolonged (38 +/- 31, 41 +/- 36, 42 +/- 33 s, respectively, P < 0.05 or P < 0.01). Water maze escape latency in B + D group on 4th day after training was longer than that of other groups (P < 0.01). There was no obvious difference in positive expression of NMDA in CA1, CA2 regions among groups (P > 0.05). The positive count of NMDA in dentate gyrus in D group (198 +/- 14) and B + D group (191 +/- 6) were lower than that of HC group (224 +/- 23, P < 0.05 or P < 0.01), but there was no obvious difference between HC group and B group (219 +/- 25, P > 0.05).

CONCLUSIONSBurn complicated with depression can reduce LMA, which may be due to a decrease in NMDA in dentate gyrus.