Irst day. The SPS protocol [8] consisted of a 2-h immobilization (compression with plastic bags), 20-min forced swim (25uC), 15-min rest, followed by ether anesthesia (until loss of consciousness). Following SPS, the rats were fed routinely. The study was approved by the ethics committee of China Medical University. Experiments were carried out in accordance with the Guidelines laid down by the NIH in the US regarding the care and use of animals for experimental procedures.Perfusion-based SectionsRats of both the normal control group and SPS groups were prepared by left ventricle perfusion with 4 paraformaldehyde in phosphate buffer (PB) and fixation, and post-fixed in the same fixative at 4uC for 6?0 h. They were then immersed in a 20 sucrose solution in 0.01 M phosphate buffer (PB, pH 7.4) at 4uC. Samples were snap-frozen in liquid nitrogen and sectioned. Coronal sections (12-mm) were prepared for the morphological studies.Terminal Title Loaded From File Transferase dUTP Nick-end Labeling (TUNEL)Dewaxed sections of 4 rats of each group were washed three times (5 min each) in 0.01 M PBS, and permeabilized in proteinase K for 10 min. Endogenous peroxidase was deactivated by 0.3 hydrogen peroxide. These sections were washed three times again. Then they were incubated with TDT at 37uC for 1 h, and incubated with antibody at 37uC for 1 h. These sections were stained by 3,30-diaminobenzidine (DAB), and after hematoxylin post-staining, were mounted and observed under light microscope. Five slides were randomly selected from each group, and in each slide, five visual fields (X40) in the hippocampus were randomly selected. The number of TUNEL-positive cells was counted with about 500 cells counted per slide. The TUNEL-positive cells rate was calculated to equal (the number of TUNEL-positive cells/total cells) X100 .Table 1. All primers for RT-PCR.Name GRP78 CaM CaMKIIa Capase-12 b-actinPrimer Sense 59-CCAAGAGAGGGTTCTTGAATCTCG -39 antisense 59-ATGGGCCAGCCTGGATATACAACA -39 Sense 59-GGCATCCTGCTTTAGCCTGAG-39 antisense 59-ACATGCTATCCCTCTCGTGTGAC-39 sense 59-CATCCTCACCACTATGCTG-39 antisense 59-ATCGATGAAAGTCCAGGCCG-3 sense 59-GCACATTCCTGGTCTTTATGTCCC-39 antisense 59-GCCACTGCTGATACAGATGAGGAA -39 sense 59-GTCACCCACACTGTGCCCATCT-39 antisense59-ACAGAGTACTTGCGCTCAGGAG-Product Size (bp) 181 bp 328 bp 284 bp 312 bp 542 bpdoi:10.1371/journal.pone.0069340.tER- Pathway is Involved in PTSD-Induced ApoptosisFigure 1. Apoptotic cells in the hippocampus was detected by TUNEL method. Morphological changes in apoptotic cells in the hippocampus of single prolonged stress (SPS) rats. The TUNEL assay was used to detect apoptotic cells in the hippocampus. (A) Control group; (B) 7 days after SPS; (C) quantification of TUNEL-positive cells (mean 6 SD), *P,0.05 vs. the control group. Scale bar 520 mm. doi:10.1371/journal.pone.0069340.gAssessing the Morphological Changes in the Hippocampus Using Transmission Electron Microscopy (TEM)Under anesthesia, 4 rats per group were perfused with 4 paraformaldehyde and 2.5 glutaraldehyde in phosphate buffer (PB). The Title Loaded From File brains were removed and immediately immersed in 2.5 glutaraldehyde in 0.1 M PB, pH 7.4 on ice, with shaking for 23977191 6 h. After sufficient washing with 0.1 M PB, the brains were cut into blocks measuring about 1 mm wide, 5 mm long, and 1 mm thick with the hippocampus at the center of the blocks. The blocks were post-fixed in 1 osmium tetroxide for 2 h at 4uC. They were rinsed in distilled water for several times, dehydrated in graded series (.Irst day. The SPS protocol [8] consisted of a 2-h immobilization (compression with plastic bags), 20-min forced swim (25uC), 15-min rest, followed by ether anesthesia (until loss of consciousness). Following SPS, the rats were fed routinely. The study was approved by the ethics committee of China Medical University. Experiments were carried out in accordance with the Guidelines laid down by the NIH in the US regarding the care and use of animals for experimental procedures.Perfusion-based SectionsRats of both the normal control group and SPS groups were prepared by left ventricle perfusion with 4 paraformaldehyde in phosphate buffer (PB) and fixation, and post-fixed in the same fixative at 4uC for 6?0 h. They were then immersed in a 20 sucrose solution in 0.01 M phosphate buffer (PB, pH 7.4) at 4uC. Samples were snap-frozen in liquid nitrogen and sectioned. Coronal sections (12-mm) were prepared for the morphological studies.Terminal Transferase dUTP Nick-end Labeling (TUNEL)Dewaxed sections of 4 rats of each group were washed three times (5 min each) in 0.01 M PBS, and permeabilized in proteinase K for 10 min. Endogenous peroxidase was deactivated by 0.3 hydrogen peroxide. These sections were washed three times again. Then they were incubated with TDT at 37uC for 1 h, and incubated with antibody at 37uC for 1 h. These sections were stained by 3,30-diaminobenzidine (DAB), and after hematoxylin post-staining, were mounted and observed under light microscope. Five slides were randomly selected from each group, and in each slide, five visual fields (X40) in the hippocampus were randomly selected. The number of TUNEL-positive cells was counted with about 500 cells counted per slide. The TUNEL-positive cells rate was calculated to equal (the number of TUNEL-positive cells/total cells) X100 .Table 1. All primers for RT-PCR.Name GRP78 CaM CaMKIIa Capase-12 b-actinPrimer Sense 59-CCAAGAGAGGGTTCTTGAATCTCG -39 antisense 59-ATGGGCCAGCCTGGATATACAACA -39 Sense 59-GGCATCCTGCTTTAGCCTGAG-39 antisense 59-ACATGCTATCCCTCTCGTGTGAC-39 sense 59-CATCCTCACCACTATGCTG-39 antisense 59-ATCGATGAAAGTCCAGGCCG-3 sense 59-GCACATTCCTGGTCTTTATGTCCC-39 antisense 59-GCCACTGCTGATACAGATGAGGAA -39 sense 59-GTCACCCACACTGTGCCCATCT-39 antisense59-ACAGAGTACTTGCGCTCAGGAG-Product Size (bp) 181 bp 328 bp 284 bp 312 bp 542 bpdoi:10.1371/journal.pone.0069340.tER- Pathway is Involved in PTSD-Induced ApoptosisFigure 1. Apoptotic cells in the hippocampus was detected by TUNEL method. Morphological changes in apoptotic cells in the hippocampus of single prolonged stress (SPS) rats. The TUNEL assay was used to detect apoptotic cells in the hippocampus. (A) Control group; (B) 7 days after SPS; (C) quantification of TUNEL-positive cells (mean 6 SD), *P,0.05 vs. the control group. Scale bar 520 mm. doi:10.1371/journal.pone.0069340.gAssessing the Morphological Changes in the Hippocampus Using Transmission Electron Microscopy (TEM)Under anesthesia, 4 rats per group were perfused with 4 paraformaldehyde and 2.5 glutaraldehyde in phosphate buffer (PB). The brains were removed and immediately immersed in 2.5 glutaraldehyde in 0.1 M PB, pH 7.4 on ice, with shaking for 23977191 6 h. After sufficient washing with 0.1 M PB, the brains were cut into blocks measuring about 1 mm wide, 5 mm long, and 1 mm thick with the hippocampus at the center of the blocks. The blocks were post-fixed in 1 osmium tetroxide for 2 h at 4uC. They were rinsed in distilled water for several times, dehydrated in graded series (.
