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Stress, specifically chronic unpredictable stress and chronic restrained stress, induce depigmentation in C57BL/6 mice. Fluoxetine promoted melanin production and the migration of melanocytes via 5-HT1A receptor and 5-HT2A receptor, respectively.<br><br>Display Omitted<br>• Fluoxetine ameliorates CUMS and CRS induced depigmentation in C57BL/6 mouse. • Fluoxetine induces melanogenesis via activating the phosphorylation of p38 MAPK signaling pathways. • 5-HT1A and 2A receptors regulated fluoxetine increased melanocyte melanogenesis and migration.<br>Background: 5-HT1A receptor was participated in fluoxetine induced melanogenesis in melanocytes and in normal C57BL/6 mice, but we know little about whether other 5-HT receptors are involved in regulation of fluoxetine promotes pigmentation.<br>Objective: To investigate the role of 5-HT receptors in regulation of fluoxetine ameliorates chronic unpredictable mild stress (CUMS) and chronic restraint stress (CRS) induce hypopigmentation in C57BL/6 mice.<br>Methods: CUMS and CRS were used to induce depigmentation in mice and evaluate the effect of fluoxetine. Western blot, immunohistochemistry and Q-PCR assay were used to determine the levels of protein and mRNA. Masson Fontana staining was used for melanin staining and FITC-Phalloidin staining was used to detect the expression of F-actin. Zebrafish and B16F10 cells were used for the mechanism research.<br>Results: Fluoxetine (2.6 mg/kg, ig) ameliorated hypopigmentation induced by CUMS and CRS in mice, significantly increased the mRNA and protein levels of 5-HT1 A and 5-HT2 A receptors in mice and B16F10 cells. The effect of fluoxetine on melanogenesis in B16F10 cells and zebrafish were inhibited by WAY100635 (a selective 5-HT1 A receptor antagonist) and ketanserin (a 5-HT2 A receptor antagonist), respectively. Activation of p38 MAPK signaling pathways was contributed to fluoxetine induced melanogenesis and inhibited by WAY100635, but not ketanserin. However, ketanserin selectively weakened the action of fluoxetine promoted migration and up-regulated Rab27a protein expression in B16F10 cells.<br>Conclusions: 5-HT1 A and 2 A receptors contribute to melanogenesis and migration property of fluoxetine. The newly revealed mechanism indicates that fluoxetine and its analogues may be a potential drug for treatment of depigmentation disorders.

Zuotai is a drug containing mercury considered to be the king of Tibetan medicine. The biosafety of Zuotai led people's attention and so far little is known about the toxicity of Zuotai to mast cells. RBL-2H3 cells which used as an alternative model of mast cells were treated with Zuotai, β-HgS and positive drug Compound 48/80 respectively. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the toxicity of drugs to RBL-2H3 cells. The degranulation of RBL-2H3 cells was studied from β-hexosaminidase, histamine, interleukin (IL)-4 and tumor necrosis factor-α (TNF-α). The result showed that Zuotai can affect the cytotoxicity and degranulation of RBL-2H3 cells and the results can provide reference for the toxicity evaluations of Tibetan medicine Zuotai.

Abstract Ethnopharmacological relevance Zuotai (gTso thal) has a long history in the treatment of cardiovascular disease, liver and bile diseases, spleen and stomach diseases as a precious adjuvant in Tibetan medicine. However, Zuotai is a mercury preparation that contains 54.5% HgS. Its application has always been controversial. Aim of the study To evaluate the toxicological effects of Zuotai in hepatocytes and in zebrafish. Materials and methods MTT was used to determine the survival rate of hepatocytes; Hoechst and TUNEL staining were used to detect the apoptosis cells; Western blot and RT-qPCR assay were used to determine the expression levels of the protein and mRNA; Liver morphology observation and H&E staining were used to evaluate the hepatotoxicity of Zuotai in Zebfrafish. Results The survival rate of L-02 cells, HepG2 cells and RBL-2A cells reduced by Zuotai (10−4–0.1 mg/mL) in a dose and time-dependent manner. Zuotai (0.1 mg/mL) induced HepG2 cells shrinkage, condensation and fragmentation and increased the number of apoptosis cells. The protein expression levels of cleaved Caspase-3 and Bax were increased and the expression levels of Bcl-2 were reduced after HepG2 cells exposed to Zuotai (10−4–0.1 mg/mL) for 24 h. In addition, Zuotai (0.2 mg/mL) induced the darker liver color of the larval zebrafish and changed the liver morphologic of adult zebrafish. Zuotai (0.2 mg/mL) also increased the mRNA levels of CYP1A1, CYP1B1 and MT-1 in the liver of adult zebrafish. However, no significantly hepatotoxicity was observed after hepatocytes and zebrafish exposed to HgS at the same dose. Conclusions Results showed that Zuotai induced hepatotoxicity effectively under a certain dose but its hepatotoxicity likely occurs via other mechanisms that did not depend on HgS. Graphical abstract Zuotai, a clinical adjuvant in Tibetan medicine, contains 54.5% HgS, which can induce apoptosis of liver cells and liver injury in zebrafish. However, HgS, the principal component of Zuotai did not exhibit hepatotoxicity at the same dose. fx1 [ABSTRACT FROM AUTHOR]

Recent evidence has established that consumption of High-fat diet (HFD)-induced obesity is associated with deficits in hippocampus-dependent memory/learning and mood states. Nevertheless the link between obesity and emotional disorders still remains to be elucidated. This issue is of particular interest during adolescence, which is important period for shaping learning/memory and mood regulation that can be sensitive to the detrimental effects of HFD. Our present study is focused to investigate behavioral and metabolic influences of short-term HFD intake in adolescent C57BL/6 mice. HFD caused weight gain, impaired glucose tolerance (IGT) and depression-like behavior as early as after 3 weeks which was clearly proved by a decrease in number of groomings in the open field test (OFT) and an increase in immobility time in the tail suspension test (TST). In the 4th week HFD induced obese model was fully developed and above behavioral symptoms were more dominant (decrease in number of crossings and groomings and increase in immobility time in both FST and TST). At the end of 6th week hippocampal analysis revealed the differences in morphology (reduced Nissl positive neurons and decreased the 5-HT<sub>1A</sub> receptor expression), neuronal survival (increased cleaved caspase-3 expression), synaptic plasticity (down regulation of <i>p</i>-CREB and BDNF), and inflammatory responses (increase in expression of pro-inflammatory cytokines and decrease in expression of anti-inflammatory cyokines) in HFD mice. Our results demonstrate that, high-fat feeding of adolescent mice could provoke “depression-like” behavior as early as 3 weeks and modulate structure, neuron survival and neuroinflammation in hippocampus as early as 6 weeks proving that adolescent age is much prone to adverse effects of HFD, which causes obesity, behavioral differences, memory and learning deficiencies.