Long-term maternal separation potentiates depressive-like behaviours and neuroinflammation in adult male C57/BL6J mice
PHARMACOLOGY BIOCHEMISTRY AND BEHAVIOR
Authors: Zhou, Lin; Wu, Zuotian; Wang, Gaohua; Xiao, Ling; Wang, Huiling; Sun, Limin; Xie, Yumeng
Abstract
Early life experience is closely related to depression caused by stress in adulthood. Early life experience, including maternal separation (MS), has been shown to evoke stress sensitivity to depression upon re-exposure to stress in adults. However, MS has also been shown to lead to resilience to stress-induced depression, which is contradictory and rarely studied. To investigate the effects of MS on depression in adults and the related mechanism, male C57/BL6J mouse pups were exposed to different MS procedures from postnatal day (PD)1 to PD21. Body weight (BW) measurements and behavioural tests (the forced swimming test (FST) and open field test (OFT)) were performed on PD41 to explore depressive and anxiety-like behaviours. Then, as adults, the mice were exposed to chronic unpredictable mild stress (CUMS) for 28 days, and then behavioural tasks were recorded. After CUMS exposure, the mice in the MS180 group (which were separated from their mothers for 3 h on PD1-PD21) showed significantly decreased time spent in the centre of the open field and reduced velocity in the OFT, a reduced latency to immobility in the FST, and decreased BW. However, the mice in the MS15 group (which were separated from their mothers for 15 min on PD1-PD21) performed similarly to NSNC mice (which were not separated from their mothers) in the behavioural tests. We further found that the expression of Ibal, a marker of neuroinflammation, was increased in the MS180 group but not in the MS15 group. In addition, our study showed decreased mRNA and protein expression of CRMP2, an important neuroprotective factor, in the MS180 group, but CRMP2 expression was unchanged in the MS15 group. This study confirmed the generation of different behavioural responses to stress exposure in adulthood due to different degrees of MS. Neuroinflammation and neuroprotection are involved, which requires further research.
miR-30 inhibits proliferation of trophoblasts in preeclampsia rats partially related to MAPK/ERK pathway
EXPERIMENTAL AND THERAPEUTIC MEDICINE
Authors: Wang, Yufeng; Jie, Luo; Gong, Haifeng; Li, Yuqin; Xie, Anxia; Li, Yanjun; Guo, Hong
Abstract
Effect of micro ribonucleic acid (miR)-30 on the proliferation of trophoblasts in preeclampsia (PE) rats through the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway was studied. The miR-30 mimic was transfected into the trophoblast HTR8/SVNEO cell lines. The effects of expression level of miR-30 on the proliferation and hypoxia-induced apoptosis of HTR8/SVNEO cells were detected via methyl thiazolyl tetrazolium (MTT) assay and Annexin V/propidium iodide staining, respectively, using the flow cytometer. A total of 30 pregnant Sprague-Dawley rats were randomly divided into control group (CTL group, n=10), PE rat group (PE group, n=10) and PE + miR-30 Mimic group (PE+agomiR-30 group, n=10) using a random number table. The protein expression levels of phosphorylated ERK (p-ERK)1/2, ERK1/2, proliferating cell nuclear antigen (PCNA) and tubulin were determined using western blot analysis, and the mRNA expression level of ERK1/2 was detected via reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The expression level of PCNA in tissues was detected via immunohistochemistry. The results of MTT assay showed that the proliferation of HTR8/SVNEO cells significantly declined in hypoxic environment, while miR-30 promoted the proliferation of HTR8/SVNEO cells and alleviated the hypoxia-induced inhibition on cell proliferation. It was found that the trophoblast apoptosis rate was increased in hypoxia group compared with that in CTL group, while it was significantly decreased in miR-30 Mimic group compared with that in hypoxia group. PE group had obviously decreased p-ERK and PCNA expression levels as well as p-ERK/ERK ratio in placental tissues compared with CTL group, while PE+agomiR-30 group had an obviously increased expression level of PCNA as well as p-ERK/ERK ratio in placental tissues compared with PE group. MiR-30 activates the MAPK/ERK signaling pathway and increases the expression level of PCNA through raising the p-ERK level and p-ERK/ERK ratio, thereby inhibiting cell apoptosis and promoting cell proliferation.