Effects of intranasal administration of glial cell line-derived neurotrophic factor on postoperative cognitive dysfunction in aged rats / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effects of intranasal administration of glial cell line-derived neurotrophic factor (GDNF) on postoperative cognitive dysfunction in aged rats.Methods:Forty healthy Sprague-Dawley rats of both sexes, aged 21-23 months, weighing 480-600 g, were divided into 4 groups ( n=10 each) using a random number table method: sham operation group (group S), operation group (group O), intranasal administration of low-dose GDNF group (group G1) and intranasal administration of high-dose GDNF group (group G2). Rats underwent exploratory laparotomy under anesthesia with chloral hydrate in O, G1 and G2 groups, while the rats in group S only received sham operation.The rats in group G1 and group G2 were intranasally treated with GDNF 25 and 50 μg (in 25 μl of PBS), respectively, and PBS 25 μl was nasally administered in group S and group O every day for 3 consecutive days after operation or sham operation.Morris water maze test was performed on days 3-7 after surgery, and then the rats were sacrificed, and hippocampal tissues were removed for determination of the expression of GDNF, high mobility group box 1 (HMGB1), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), activated caspase-3 and Bax (by Western blot). Results:Compared with group S, the escape latency was significantly prolonged on days 5-7 after operation, the number of crossing the platform was reduced, time spent in the target quadrant was shortened, expression of GDNF was down-regulated, and expression of IL-1β, TNF-α, HMGB1, activated caspase-3 and Bax in hippocampi was up-regulated in group O, and the number of crossing the platform was reduced, time spent in the target quadrant was shortened, and expression of IL-1β and TNF-α was up-regulated in G1 and G2 groups ( P<0.05). Compared with group O, the escape latency was significantly shortened on days 5-7 after operation, the number of crossing the platform was increased, time spent in the target quadrant was prolonged, expression of GDNF was up-regulated, expression of TNF-α, HMGB1, activated caspase-3 and Bax in hippocampi was down-regulated in G1 and G2 groups, and IL-1β in hippocampi was down-regulated in group G1 ( P<0.05). Compared with group G1, the expression of TNF-α in hippocampi was down-regulated ( P<0.05), and no significant change was found in the other parameters mentioned above in group G2 ( P>0.05). Conclusions:Intranasal administration of GDNF can improve postoperative cognitive dysfunction, and the mechanism may be related to inhibiting neuroinflammatory responses and neuroapoptosis in aged rats.