Long-term spaceflight composite stress induces depressive behaviors in model rats through disrupting hippocampus synaptic plasticity.

INTRODUCTION: Long-term spaceflight composite stress (LSCS) can cause adverse effects on human systems, including the central nervous system, which could trigger anxiety and depression. AIMS: This study aimed to identify changes in hippocampus synaptic plasticity under LSCS. METHODS: The present study simulated the real long-term space station environment by conducting a 42-day experiment that involved simulating microgravity, isolation, noise, circadian rhythm disruptions, and low pressure. The mood and behavior of the rats were assessed by behavior test. Transmission electron microscopy and patch-clamp were used to detect the changes in synapse morphology and electrophysiology, and finally, the expression of NMDA receptor channel proteins was detected by western blotting. RESULTS: The results showed that significant weight loss, anxiety, and depressive behaviors in rats were observed after being exposed to LSCS environment for 42 days. The synaptic structure was severely damaged, manifested as an obvious decrease in postsynaptic density thickness and synaptic interface curvature (p < 0.05; p < 0.05, respectively). Meanwhile, LTP was significantly impaired (p < 0.0001), and currents in the NMDAR channel were also significantly reduced (p < 0.0001). Further analysis found that LSCS decreased the expression of two key subtype proteins on this channel. CONCLUSION: These results suggested that LSCS-induced depressive behaviors by impairing synaptic plasticity in rat hippocampus.

[Big data analysis of coastal illegal fishing from the perspective of compensation of ecological and environmental damage]. / 生态环境损害赔偿视域下的近海非法捕捞大数据分析.

Illegal fishing is one of the sources of marine ecological damage. The implementation of compensation of ecological and environmental damage in this field is poorly understood. In this study, we examined data pertaining to coastal illegal fishing cases during 2018-2022 using the big data publicly made available by China Judgement Online. The main results included: 1) there are numerous types of illegal fishing, and more efforts should focus on the nature and extent of illegal fishing, with electrofishing and trawl being suitable entry points; 2) Special attention should be paid to the variation characteristics of rakes in the range of high illegal catch weight and value. It was suggested to optimize and adjust its management mode to avoid the frequent occurrence of such illegal fishing cases of rake; 3) The varieties of assessment models increased the uncertainty of damages computation, which might be reduced by establishing strong criteria for value quantification and damage assessment; 4) There is limited scientific support for the compensation for releasing the most popular ecological restoration technique for illegal fishing. As a result, the "compensation" design for "restoration" should be implemented, while the potential for additional restoration methods should be investigated.

"Integrative learning" promotes learning but not memory in older rats.

Background: We had previously advanced the concept of "Integrative Learning", that is, "under the role of 'meta-learning self', learners actively integrate learning materials to achieve rapid and in-depth understanding of knowledge", and designed an animal behavioral model to compare the effects of "Integrative Learning" (IL) vs. "Progressive Learning" (PL) in young rats. It was found that IL is more advantageous than PL. Here, we aim to examine whether the same phenomenon persist in older rats. Methods: Fifteen 12-month-old male Sprague-Dawley (SD) rats were selected as subjects and randomly divided into the IL group and the PL group, and a 14-unit integrative T-maze was constructed for the study. Training and testing procedures contained three stages: the learning stage, the memory retention test stage and the Gestalt transfer learning stage. Data on young rats (1-month-old) from the previous study were also drawn here for comparisons on learning performance. Results: (1) The 12-session learning stage can be divided into three sub-stages as each sub-stage represented the new opening of one third of the whole path in the PL group. There were significant interactions in total errors made between groups and sessions: the PL group had significantly fewer errors during Sub-stage One due to a much shorter path to be learned, however, the IL group's errors made sharply dropped as learning progressed into Sub-stage Two and Three, and were maintained at a significantly lower level than the PL group during Sub-stage Three. (2) When compared with young rats, age had a main effect on the number of errors made-the 1-month-old groups learned overall better and faster than the older groups, whereas the pattern of group differences between the IL and PL learning modes remained consistent across young and older groups. (3) Unlike young rats, during the memory retention test stage and the Gestalt transfer learning stage, the IL group did not perform better than the PL group in older rats. Conclusions: (1) "Integrative Learning" promotes learning but not memory in older rats. (2) Higher-order cognitive abilities that support meta-cognition, long-term retention and knowledge transfer might be deteriorating in older rats.