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PMID: 25063071 DOI: 10.1016/S1995-7645(14)60066-3 | |
2. Materials and methods | |
2.1. Animals | |
A total of 80 healthy 7-day-old SD rats, male or female, | |
weighing 12-18 g were selected. All animals were provided | |
by XX University Experimental Animal Center, and were | |
kept in a constant temperature 25 ℃, constant humidity | |
40% -50% environment, and had freely drank autoclaved | |
water. | |
2.2. Main reagents and instruments | |
Optical microscope was purchased from Japanese Nikon | |
company,German Leica Microtome was purchased from | |
Dalian Dajian Medical Devices Co., Ltd., Micro pipette and | |
homogenizer were purchased from the German Eppendorf | |
Company, -80 ℃ refrigerator were purchased from China | |
Haier Company. TUNEL assay kit was purchased from Roche | |
Company, IL-4, IL-1毬 and IgE radioimmunoassay kit were | |
purchased from Wuhan Boster Biological Engineering Co., | |
Ltd., Ketamine (100 mg/10 mL) were purchased from Jiangsu | |
Hengrui Limited Company, propofol injection (200 mg/20 mL) | |
were purchased from Sichuan Shule Pharmaceutical | |
Corporation. Experimental animal cages, precision electronic | |
balance, 0.9% saline solution, hematoxylin, eosin staining | |
solution were provided by the laboratory. | |
2.3. Experimental methods | |
2.3.1. Experimental animal model and grouping methods | |
A total of 80 young rats were randomly divided into | |
four groups (the control group, experimental group A, | |
experimental group B, experimental group C) (n=20). All | |
young rats received the adaptive breeding for 1 week in | |
animal room. The animals in the control group received 0.9% | |
saline l mL by intraperitoneal injection every 2 h, continuous | |
for 3 times. The animals in experiment group A received 80 mg/kg | |
ketamine l mL by intraperitoneal injection every 2 h, | |
continuous for 3 times. The animals in experiment group B | |
received 80 mg/kg propofol 1 mL by intraperitoneal injection | |
every 2 h, continuous for 3 times. The animals in experiment | |
group C received 80 mg/kg ketamine and propofol 1 mL by | |
intraperitoneal injection every 2 h, continuous for 3 times. | |
The injection volume was 1 mL, and if it was less than l mL it | |
was supplemented by saline. Half of rats in each group were | |
randomly sacrificed after 15 min of anesthesia, the other half | |
underwent Morris water maze test 3 weeks later. All died | |
or abandoned animals in midway were supplemented by | |
modeling again. | |
2.3.2. Immune parameters detection | |
Using heparinization disposable 5 mL sterile syringe, 2 mL | |
blood was obtained by percutaneous puncture at the point | |
of maximal impulse and then it was injected into sterile EP | |
tube. After 30 min at 4 ℃, it was centrifuged at 3 000 r/min at | |
low temperature for 10 min. Serum was separated and stored | |
at -80 ℃ for the test. Serum IL-2, IL-4 and IL-10 levels | |
were detected by ELISA. | |
2.3.3. Brain tissue specimen collection, preparation and | |
indicators test | |
After blood collection, half of the young rats were randomly | |
perfusion needle was inserted to the ascending aorta from | |
the left ventricle, and fixed. The right auricle was cut. It | |
was washed at 4 ℃ saline by perfusion needle until the | |
effluent of the right atrium was clear. Then it was fixed | |
by 4% paraformaldehyde phosphate buffer. Hippocampal | |
was isolated from the brain tissue when the body tissues | |
and organs were hard, they were paraffin-embedded | |
and cut. Neuronal apoptosis detection was performed by | |
terminal deoxynucleotidyl transferase-mediated nick end | |
labeling (TUNEL) method. TUNEL-positive cells showed | |
brown particles in the nucleus. Six horizons were randomly | |
selected and average optical density was measured. | |
Positive intensity and the apoptotic index were calculated. | |
The formula was as follow: apoptotic index (AI) = MOD × | |
Area% × 100, MOD represents the average gray level; area% | |
represents the percentage of the total positive nucleus area | |
in the total nucleus area. The other half young rats cerebral | |
was obtained quickly by sterile opening cranium, and brain | |
tissue was mixed with ice normal saline by homogenizer. | |
10% brain homogenate was prepared at 4 ℃, and centrifuged | |
at 3 000 r/min for 15 min. The supernatant was stored at | |
-80 ℃ for test. Whole brain IL-1毬 levels were detected by | |
ELISA. | |
2.3.4. Morris water maze test | |
Behavior of rats was observed by Morris water maze[3]. | |
Round tank has four quadrants. A black platform was fixed | |
at the fourth quadrant, located 1 cm underwater. The rats | |
were put into the water of a randomly select quadrant, | |
swim tracks of the rats were recorded with a camera. How | |
long rats find the platform is the latency. After this test, the | |
platform was removed and the rats were put into water from | |
the same water-entering point, the times of crossing the | |
former platform were measured. | |
2.4. Statistical analysis | |
Data were expressed as mean依SD values and analyzed with | |
SPSS 13.0 software. After the variance test, the difference | |
between two groups was compared with single factor analysis | |
of variance. P<0.05 was considered as statistical significant | |
difference. | |