Effects of Phellinus linteus Administration on Serotonin Synthesis in the Brain and Expression of Monocarboxylate Transporters in the Muscle during Exhaustive Exercise in Rats

Phellinus linteus activates Treg cells via FAK to promote M2 macrophage polarization in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most prevalent malignant tumor worldwide. Within HCC's tumor microenvironment, focal adhesion kinase (FAK) plays a critical role. Regulatory T cells (Treg) modulate the polarization of tumor-associated macrophages , but the relationship between FAK, Treg cells, and macrophages remains underexplored. Phellinus linteus (PL) shows promise as a treatment for HCC due to its pharmacological effects. This study aimed to explore the relationship between FAK and Treg-macrophages and to assess whether PL could exert a protective effect through the FAK process in HCC. Initially, C57BL/6-FAK-/- tumor-bearing mice were utilized to demonstrate that FAK stimulates HCC tumor development. High dosages (200 μM) of FAK and the FAK activator ZINC40099027 led to an increase in Treg (CD4+CD25+) cells, a decrease in M1 macrophages (F4/80+CD16/32+, IL-12, IL-2, iNOS), and an increase in M2 macrophages (F4/80+CD206+, IL-4, IL-10, Arg1, TGF-β1). Additionally, FAK was found to encourage cell proliferation, migration, invasion, and epithelial-mesenchymal transition while inhibiting apoptosis in HepG2 and SMMC7721 cells. These effects were mediated by the PI3K/AKT1/Janus Kinase (JAK)/ signal transducer and activator of transcription 3 (STAT3), and mitogen-activated protein kinase (p38 MAPK)/Jun N-terminal Kinase (JNK) signaling pathways. Furthermore, PL exhibited a potent antitumor effect in vivo in a dose-dependent manner, reducing FAK, Treg cells, and M2 macrophages, while increasing M1 macrophages. This effect was achieved through the inhibition of the PI3K/AKT/JAK/STAT3, and p38/JNK pathways. Overall, our findings suggest that FAK promotes HCC via Treg cells that polarize macrophages toward the M2 type through specific signaling pathways. PL, acting through FAK, could be a protective therapy against HCC.

The effects of forced exercise and zinc supplementation during pregnancy on prenatally stress-induced behavioral and neurobiological consequences in adolescent female rat offspring

Prenatal manipulations can lead to neurobehavioral changes in the offspring. In this study, individual and combined effects of forced exercise and zinc supplementation during pregnancy on prenatally restraint stress (PRS)-induced behavioral impairments, neuro-inflammatory responses, and oxidative stress have been investigated in adolescent female rat offspring. Pregnant rats were divided into five groups: control; restraint stress (RS); RS + exercise stress (RS + ES), RS + zinc supplementation (RS + Zn); and RS + ES + Zn. All the pregnant rats (except control) were exposed to RS from gestational days 15 to 19. Pregnant rats in ES groups were subjected to forced treadmill exercise (30 min/daily), and in Zn groups to zinc sulfate (30 mg/kg/orally), throughout the pregnancy. At postnatal days 25-27, anxiety-like and stress-coping behaviors were recorded, and the gene expressions of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) and the concentration of total antioxidant capacity were measured in the prefrontal cortex. PRS significantly enhanced anxiety, generated passive coping behaviors, increased IL-1β and TNF-α expression, and decreased the antioxidant capacity. ES potentiated while zinc reversed PRS-induced behavioral impairments. Prenatal zinc also restored the anti-inflammatory and antioxidant capacity but had no effect on additive responses imposed by the combination of RS and ES. Suppression of PRS-induced behavioral and neurobiological impairments by zinc suggests the probable clinical importance of zinc on PRS-induced changes on child temperament.

Hypothalamic TRH mediates anorectic effects of serotonin in rats

Among the modulatory functions of thyrotropin-releasing hormone (TRH), an anorectic behavior in rodents is observed when centrally injected. Hypothalamic PVN neurons receive serotonergic inputs from dorsal raphe nucleus and express serotonin (5HT) receptors such as 5HT1A, 5HT2A/2C, 5HT6, which are involved in 5HT-induced feeding regulation. Rats subjected to dehydration-induced anorexia (DIA) model show increased PVN TRH mRNA expression, associated with their decreased food intake. We analyzed whether 5HT input is implicated in the enhanced PVN TRH transcription that anorectic rats exhibit, given that 5HT increases TRH expression and release when studied in vitro By using mHypoA-2/30 hypothalamic cell cultures, we found that 5HT stimulated TRH mRNA, pCREB and pERK1/2 levels. By inhibiting basal PKA or PKC activities or those induced by 5HT, pCREB or pERK1/2 content did not increase suggesting involvement of both kinases in their phosphorylation. 5HT effect on TRH mRNA was not affected by PKA inhibition, but it diminished in the presence of PKCi suggesting involvement of PKC in 5HT-induced TRH increased transcription. This likely involves 5HT2A/2C and the activation of alternative transduction pathways than those studied here. In agreement with the in vitro data, we found that injecting 5HT2A/2C antagonists into the PVN of DIA rats reversed the increased TRH expression of anorectic animals, as well as their decreased food intake; also, the agonist reduced food intake of hungry restricted animals along with elevated PVN TRH mRNA levels. Our results support that the anorectic effects of serotonin are mediated by PVN TRH in this model.Significance statementInteraction between brain peptides and neurotransmitters' pathways regulates feeding behavior, but when altered it could lead to the development of eating disorders, such as anorexia. An abnormal increased TRH expression in hypothalamic PVN results in dehydration-induced anorectic rats, associated to their low food intake. The role of neurotransmitters in that alteration is unknown, and since serotonin inhibits feeding and has receptors in PVN, we analyzed its participation in increasing TRH expression and reducing feeding in anorectic rats. By antagonizing PVN serotonin receptors in anorectic rats, we identify decreased TRH expression and increased feeding, suggesting that the anorectic effects of serotonin are mediated by PVN TRH. Elucidating brain networks involved in feeding regulation would help to design therapies for eating disorders.

Analysis of the anti-fatigue activity of polysaccharides from Spirulina platensis: role of central 5-hydroxytryptamine mechanisms

This study evaluated the effects of polysaccharides from Spirulina platensis (PSP) on endurance during treadmill exercise; levels of some biochemical indicators and expressions of serotonin related genes in the caudate putamen of exercising rats.

Effect of sildenafil citrate on brain central fatigue after exhaustive swimming exercise in rats

Sildenafil citrate, a potent and selective inhibitor of phosphodiesterase type-5, is used clinically to treat erectile dysfunction and pulmonary arterial hypertension. We investigated the effect of sildenafil citrate on brain central fatigue through serotonin (5-hydroxytryptamine, 5-HT) synthesis after exhaustive swimming exercise in rats. The rats in the sildenafil citrate-treated groups received sildenafil citrate orally once a day for 14 consecutive days at respective dosage. On the 14 days after starting experiment, each animal was submitted to swimming test with intensity equivalent to overload. The exhaustion was defined as a state in which coordinated movements did not return to the water surface for breathing within 10 sec. Immunohistochemistry for 5-HT, tryptophan hydroxylase (TPH), and western blot for serotonergic type 1A (5-HT1_A) receptor and 5-HT transporter (5-HTT) were performed. Exhaustive swimming exercise increased 5-HT and TPH expressions in the dorsal raphe and sildenafil citrate suppressed 5-HT and TPH expressions in the exhaustive swimming exercise rats. Exhaustive swimming exercise increased 5-HT1_A receptor and 5-HTT expressions in the dorsal raphe and sildenafil citrate suppressed 5-HT1_A receptor and 5-HTT expressions in the exhaustive swimming exercise rats. The significant suppressing effect appeared in the 20-mg/kg sildenafil citrate. Sildenafil citrate might be proposed as a potential ergogenic aid through anticentral fatigue.

Treadmill Exercise Ameliorates Chemotherapy-Induced Muscle Weakness and Central Fatigue by Enhancing Mitochondrial Function and Inhibiting Apoptosis

Purpose

Chemotherapy is associated with the side effects including damage to the mitochondrial DNA. Doxorubicin (DOX) serves as a chemotherapeutic agent for the patients with breast cancer or prostate cancer. DOX causes muscle weakness and fatigue. We investigated the effects of treadmill exercise on DOX-induced apoptosis and mitochondrial dysfunction in relation to central fatigue. For this study, we used the rat model of DOX-induced muscle damage.

Methods

DOX (2 mg/kg) was intraperitoneally injected 1 time per week for 4 weeks. Treadmill running continued 5 days per week for 4 weeks. Muscle strength and fatigue index in the gastrocnemius were measured. Immunohistochemistry for the expressions of tryptophan hydroxylase (TPH) and 5-hydroxytryptamine (5-HT) in the dorsal raphe was conducted. We used western blot analysis for the expressions of Bax, Bcl-2, and caspases-3 in the gastrocnemius. Mitochondrial function in the gastrocnemius was also evaluated.

Results

DOX treatment decreased muscle strength with increase of fatigue index in the gastrocnemius. Mitochondria function was deteriorated and apoptosis in the gastrocnemius was enhanced by DOX treatment. Expressions of TPH and 5-HT in the dorsal raphe were increased by DOX treatment. Treadmill exercise attenuated DOX-induced muscle fatigue and impairment of mitochondria function. Apoptosis in the gastrocnemius was inhibited and over-expression of TPH and 5-HT was suppressed by treadmill exercise.

Conclusions

Apoptosis was enhanced and mitochondria function was deteriorated by DOX treatment, resulting in muscle weakness and central fatigue. Treadmill exercise suppressed apoptosis and prevented deterioration of mitochondria function in muscle, resulting in alleviation of muscle weakness and central fatigue during DOX therapy.

Antifatigue Functions and Mechanisms of Edible and Medicinal Mushrooms

Fatigue is the symptom of tiredness caused by physical and/or psychological stresses. As fatigue is becoming a serious problem in the modern society affecting human health, work efficiency, and quality of life, effective antifatigue remedies other than pharmacological drugs or therapies are highly needed. Mushrooms have been widely used as health foods, because of their various bioactive constituents such as polysaccharides, proteins, vitamins, minerals, and dietary fiber. This paper reviews the major findings from previous studies on the antifatigue effects, the active components of mushrooms, and the possible mechanisms. Many studies have demonstrated the antifatigue effects of edible and medicinal mushrooms. These mushrooms probably mitigate human fatigue through effects on the functional systems, including the muscular, cardiovascular, hormone, and immune system. The bioactive constituents that contribute to the antifatigue effects of mushrooms may include polysaccharides, peptides, nucleosides, phenolic compounds, and triterpenoids. Further research is still needed to identify the active ingredients and to investigate their mechanism of action on the antifatigue effects. Since most previous studies have been carried out in animal models, more human trials should be performed to verify the antifatigue function of edible and medicinal mushrooms.

Effects of colostrum serum on the serotonergic system in the dorsal raphe nuclei of exercised rats

[Purpose]

The central fatigue hypothesis suggests that exhaustion, or the maximum level of exercise, induces excessive stress and increases serotonin concentrations in the brain, which in turn decreases central nervous system (CNS) function and induces fatigue. Our aim was to determine the effects of colostrum serum on the serotonergic system in the dorsal raphe nuclei during exhaustive exercise.

[Methods]

Animals were randomly divided into five groups: control, exercise, exercise and treatment with 50, 100, and 200 mg/kg of colostrum serum. The rats in the colostrum serum treatment groups were fed colostrum serum at three different doses of 50, 100, and 200 mg/kg per day for seven days. The rats in the control and exercise groups received water by oral gavage once per day for seven days.

[Results]

The time to exhaustion in response to treadmill running increased after treatment with colostrum serum. These results show that exhaustive exercise led to over activation of the serotonergic system in the dorsal raphe nuclei, and that treatment with colostrum serum suppressed of the exercise-induced expression of tryptophan hydroxylase (TPH) and serotonin (5-HT). The results also indicated that exhaustive exercise induced 5-HT_1A autoreceptor and serotonin transporter (5-HTT) overexpression in the dorsal raphe nuclei, and that colostrum serum treatment suppressed exhaustive exercise-induced 5-HT_1A and 5-HTT expression in the dorsal raphe nuclei. The most effective dose of colostrum serum was 100 mg/kg.

[Conclusion]

Overall, our study suggests that colostrum serum has positive effects on exercise performance and recovery by increasing the resistance to fatigue.

Treadmill exercise ameliorates intracerebral hemorrhage-induced depression in rats

Intracerebral hemorrhage (ICH) is a severe type of stroke causing neurological dysfunction with high mortality rate. Depression is one of the most common complications of ICH. In the present study, the effects of treadmill exercise on ICH-induced depressive symptoms in relation with apoptosis were investigated using rats. ICH rat model was induced by injection of collagenase into the hippocampus using stereotaxic instrument. Open field test for activity and forced swimming test for depressive symptoms were conducted. Apoptosis in the hippocampus was detected using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, immunohistochemistry for caspase-3, and western blot for Bcl-2 and Bax. Western blot analysis for 5-hydroxy-tryptamine (5-HT, serotonin) and tryptophan hydroxylase (TPH) in the dorsal raphe was also conducted for biomarkers of depression. In the present results, immobility time was increased and climbing time was decreased by induction of ICH and treadmill exercise inhibited immobility time and increased climbing time in ICH rats. DNA fragmentation and caspase-3 expression in the hippocampal dentate gyrus were enhanced by induction of ICH and treadmill exercise suppressed ICH-induced DNA fragmentation and caspase-3 expression. Bax expression in the hippocampus was increased by induction of ICH and treadmill exercise inhibited Bax expression in the ICH rats. Expressions of 5-HT and TPH in the dorsal raphe were decreased by induction of ICH and treadmill exercise increased expressions of 5-HT and TPH in the ICH rats. In the present study, treadmill exercise ameliorated depressive symptoms through inhibiting apoptosis.

Effect of fermented porcine placenta on physical fatigue in mice

The fatigue spreads among the people who live under stressful life and brings about a negative impact on physical function. Here we evaluated the anti-fatigue effects of fermented porcine placenta (FPP) and main constituents, lysine (Lys) and leucine (Leu) with treadmill stress test and forced swimming test (FST) in animal models. The mice were administrated with FPP, Lys, and Leu for 21 days. After treadmill exercise, FPP, Lys, and Leu significantly reduced fatigue-related biochemical parameters, including lactate, lactate dehydrogenase, glucose, creatine kinase, urea nitrogen, cortisol, and pro-inflammatory cytokines, whereas superoxide dismutase activity and glycogen levels were significantly increased by FPP, Lys, and Leu. In the FST, FPP, Lys, and Leu significantly decreased immobility times and up-regulated brain-derived neurotrophic factor expression in brain. Furthermore, FPP, Lys, and Leu significantly decreased production of tumor necrosis factor-α, interleukin (IL)-6, IL-1β, and IL-4 through blockade of caspase-1/nuclear factor-κB pathway in stimulated splenocytes. In addition, FPP, Lys, and Leu significantly promoted proliferation of splenocytes. In conclusion, these findings suggest the potential of FPP as a novel functional food for the regulation of fatigue.

The effects of Acorus tatarinowii Schott on 5-HT concentrations, TPH2 and 5-HT1B expression in the dorsal raphe of exercised rats

ETHNOPHARMACOLOGICAL RELEVANCE

Acorus tatarinowii Schott (Shi Chang Pu) belongs to the family of Acoraceae. The plant is used as an important herb for prolonging life many years in traditional Chinese medicine. It is an ancient herbal tonic nutriment and can be used as anti-fatigue medicine. However, the effects of Acorus tatarinowii Schott on the endurance exercise in relation to central nervous system have not yet been clarified. In this study, the effects of Acorus tatarinowii Schott on treadmill running endurance, 5-HT concentrations, TPH2, 5-HT1B expression in the dorsal raphe of exercised rats were investigated.

MATERIALS AND METHODS

Sixty adult male Sprague-Dawley rats were randomly divided into six groups: the normal group, the exercise group, the exercise and the rhizomes of Acorus tatarinowii Schott (ATS)(1mg/kg)-treated group, the exercise and ATS (10mg/kg)-treated group, the exercise and ATS (100mg/kg)-treated group, the exercise and caffeine (10mg/kg)-treated group. The effects of Acorus tatarinowii Schott on endurance exercise were determined by the time to exhaustion during treadmill exercise. The detection of 5-HT concentrations in the dorsal raphe was performed by HPLC analysis. The levels of TPH2, 5-HT1A and 5-HT1B expression were measured by western blot analysis and real-time PCR.

RESULTS

We found Acorus tatarinowii Schott could prolong the time to exhaustion in treadmill exercise and suppress the exercise-induced increase of 5-HT synthesis, TPH2 mRNA and protein expression and prevent the exercise-induced decrease of 5-HT1B mRNA and protein expression in the dorsal raphe. Acorus tatarinowii Schott was as effective as caffeine in prolonging the exhaustion time in treadmill running and in decreasing the exercise-induced increase of 5-HT synthesis and TPH2 mRNA and protein expression and in preventing the exercise-induced decrease of 5-HT1B mRNA and protein expression in the dorsal raphe.

CONCLUSIONS

The results indicated that the effects of Acorus tatarinowii Schott in inhibiting the exercise-induced synthesis of 5-HT and TPH2 expression and in preventing the exercise-induced decrease of 5-HT1B expression in the dorsal raphe might be the anti-fatigue mechanism of Acorus tatarinowii Schott.

The impact of duration of one bout treadmill exercise on cell proliferation and central fatigue in rats

The purpose of this study was to investigate the impact of the duration-dependence of the one bout treadmill exercise on cell proliferation, stress, and central fatigue in rats. The animals were randomly divided into five groups: the non-exercise group, 1-h exercise group, 2-h exercise group, 4-h exercise group, and 6-h exercise group. The exercise load consisted of running at speed of 13 meters/min with the 0° inclination. Cell proliferation in the hippocampal dentate gyrus was increased in response to one bout moderate treadmill exercise in all exercise groups. But there was no statistical significance between the exercise duration and cell proliferation. The optical density of glucocorticoid (GR)-positive cells in the hippocampal dentate gyrus was not changed by treadmill exercise at any exercise duration. Expressions of serotonin (5-hydroxytryptamine, 5-HT) and tryptophan hyroxylase (TPH) were increased by treadmill exercise only at 6 h duration. It seemed like that there was no additional benefits on cell proliferation over 2 h exercise due to stressful factors with over exercise dose, and there was no change of GR expression due to early assessment point of time. It can be suggested that the one-bout of moderate treadmill exercise increased cell proliferation, but treadmill exercise prolonged to 6 h induced central fatigue in rats.

Involvement of serotonin mechanism in methamphetamine-induced chronic pulmonary toxicity in rats

The widest distribution and the highest uptake of methamphetamine (MA) in the human body occurred in the lungs, so that more and more attention should be paid to MA-induced pulmonary toxicity. MA induces the release of serotonin, which is an important mediator in pulmonary disease. The purpose of this study is to investigate the chronic response of the lung to MA and its potential mechanism in rats. Models of the chronic toxicity of MA were established with MA of 5 mg/kg and 10 mg/kg (intraperitoneally, twice per day) for 5 weeks. It was found that the high dose of MA induced rat pulmonary toxicity: crowded lung parenchyma, thickened septum, reduced number of alveolar sacs, inflammatory cell infiltration, and pulmonary arteriolar remodeling. In addition, MA resulted in a significant increase in the lung serotonin concentration and the marked upregulation of tryptophan hydroxylase 1, vesicular monoamine transporter 2, serotonin transporter, and downregulation of monoamine oxidase-A. These findings suggest that MA induced chronic pulmonary toxicity, which is concerned with the elevated serotonin concentration in rat lungs by increased synthesis, reduced metabolism, augmented accumulation, and promoted release of serotonin.