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Objective To explore the dynamic changes of hippocarnpal volumes by MRI and their behavioral changes in rat depression models before and after antidepressant treatment, and their significance. Methods Based on the evaluation of ethology, 80 SD rats were randomly divided into 3groups: control group (n=10), depression group (n=10), and treatment group (n=60) which was equally divided into 3 subgroups (group A, B and C), given 2 different treatments as self-recovery or Fluoxetine intraperitoneal injection in the 4th, 6th and 8th week. The depression models were established by chronic unpredictable mild stress or isolated feeding for 8 weeks. The body weight and fluid consumption were measured before the antidepressant treatment and every 2 weeks of the treatment, and Morris water maze test was performed and the bilateral hippocampal volumes by high field MRI were measured before and after the antidepressant treatment and every 2 weeks of the treatment. Results The behavioral data indicated that the rat depression models were established successfully and these indexes were changed dynamically. In the 4th week, as compared with those of the control rats, the left hippocampal volumes of depression rats were significantly decreased (P＜0.05), while the right ones were not significantly different. In the 6th week, as compared with those of the control rats, the right ones began to significantly decrease the volume (P＜0.05), and the left ones kept decreasing. By self-recovery, the ethology changed better in the prophase but worsened in the mid-late phase, and the hippocampal volumes had no significant change. By Fluoxetine treatment, the ethology changed better, and the left hippocampal volumes had significant changes only in the prophase. Conclusion The behavior and hippocampal volumes in rat depression models change dynamically, and after treatment, the ethology and hippocampal volumes change differentially.
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<p><b>OBJECTIVE</b>To analyze expression characteristics of human skin epidermal stem cell at different developmental stages, and to explore its biological significance.</p><p><b>METHODS</b>Health skin samples from 28-32 w fetuses (F group), 4-12 y children (C group), and 35-55 y adult (A group) were harvested, with 10 cases in each group. Epidermis were separated using trypsin digestion and EDTA, and human epidermal stem cells were isolated and purified with type IV collagen attachment method. The monoclonal antibody of integrin beta1 and keratin 19 were used for detection and identification of epidermal stem cells by immunohistochemical staining. Total RNA was extracted from above cells by Trizol one-step method, and were detected by formaldehyde denaturing agarose gel electrophoresis. Probes were prepared and hybridized into cDNA microarray for scanning fluorescent signals and analysis of images, with two-fold differential expression value for screening. Significantly up/down-regulated genes were selected for verification by real time RT-PCR.</p><p><b>RESULTS</b>By comparing expression profile between A and C groups, a total of 1808 genes with differential expression were detected, including 1089 up-regulated genes and 719 down-regulated genes, and they were classified into 128 categories. Among them, 1462 genes were known (found in GeneBank), 346 genes were unknown. A total of 4534 genes with differential expression were detected between C and F groups, in which 1783 genes were up-regulated and 2751 genes were down-regulated, and they were classified into 216 categories. Among them, 3577 genes were known (found in GeneBank), and 957 genes were unknown. There were 1104 genes with differential expression consistently detected in F, C and A groups, which were classified into 32 categories according to gene function. Among them, 94 genes were consistently up-regulated and 75 genes consistently down-regulated. Test results of real time RT-PCR were in accordance with above-mentioned results.</p><p><b>CONCLUSIONS</b>Gene expression profiles of epidermal stem cells cultured in vitro, harvested from fetuses, children, and adult, exhibit obvious difference. This may be closely related to different stages of proliferation and differentiation of human epidermal stem cell and self-repair ability of wound at different developmental stages.</p>