Research progress on the correlation between circadian rhythm and clock genes and the pathogenesis of diabetic retinopathy / 国际眼科杂志(Guoji Yanke Zazhi)

Diabetic retinopathy(DR)is the most common microvascular complication of patients with diabetes mellitus, and it has become one of the leading causes of visual impairment among working-age people worldwide. The pathogenesis of DR is complicated with multiple mechanisms. Plenty of studies have indicated that circadian rhythm and clock genes are closely related to the pathogenesis of DR. Circadian rhythm is a physiological process regulated by clock genes, which takes 24h as a cycle and is consistent with the changes of light and dark outside. Circadian rhythm regulates various physiological activities of the body. The disturbance of circadian rhythm induces DR by affecting the blood glucose level and the physiological homeostasis of the eye in patients with diabetes mellitus, and clock genes may be involved in the pathogenesis of DR by regulating oxidative stress response, inflammatory response, retinal autophagy rhythm, mitochondrial dysfunction and endothelial progenitor cell function. This paper will introduce the generation and regulation mechanism of circadian rhythm, as well as the internal circadian rhythm of retina, and further discuss the influence of circadian rhythm and clock genes on the occurrence and development of DR, aiming to provide a reference for the prevention and treatment of DR.

Research progress on the biological clock genes and diabetic retinopathy / 中华眼底病杂志

Diabetic retinopathy (DR) is one of the most common and serious complication of diabetes mellitus, which is the main cause of vision loss in adults. Biological clock genes produce circadian rhythms and control its operation, while the disorder of the expression causes the occurrence and development of a series of diseases. It has been demonstrated that biological clock genes might take effects in the development and progression of DR. On the one hand, circadian rhythm disorder-related behavior disrupts the circadian oscillation of clock genes, and the change in its expression level is prone to unbalanced regulation of glucose metabolism, ultimately increasing the risk of type 2 diabetes mellitus and DR pathogenesis. On the other hand, DR patients exhibit symptoms of circadian rhythm disorders, and it has been suggested that the clock genes may control the development and progression of DR by affecting a variety of retinal pathophysiological processes. Therefore, maintaining normal circadian rhythm can be used as a disease prevention strategy, and studying the molecular mechanism of clock genes in DR can provide new ideas for more comprehensive elaboration of the pathogenesis of DR and search for new therapeutic targets.

Circadian rhythm and health: dialogue between traditional Chinese medicine and modern medicine / 中国中药杂志

Circadian rhythm refers to the daily rhythmic variations in an organism. The irregular lifestyles of modern humans have led to a high incidence of chronic diseases, highlighting an inseparable relationship between disrupted circadian rhythm and disease development. TCM has long discussed rhythmic variations, with records dating back to the Yellow Emperor's Inner Canon(Huang Di Nei Jing), which laid a rich theoretical foundation for the research on circadian rhythm. Modern medical research has provided a more comprehensive explanation of its molecular mechanisms. This article integrated the current understanding of circadian rhythm in both Chinese and western medicine, emphasizing the crucial relationship between rhythm regulation and disease treatment. By highlighting the interdisciplinary nature of the two fields, it offers new directions for exploring the field of chronomedicine.

Research update on relationship between circadian rhythm genes and colorectal cancer / 中国病理生理杂志

Biological clock genes are essential for regulating various biological processes such as sleep,endo-crine metabolism,and cell proliferation and differentiation.These genes govern the circadian system with approximately 24-h cycles in all living organisms.Recent studies have focused on uncovering the connection between circadian rhythms and tumors.Although the expression of circadian rhythm genes and their proteins is stable in normal tissue cells,in tumor cells,such as colorectal cancer tissues,the expression of these genes is often abnormally up-regulated or down-regulated,which indicates a strong correlation between the abnormal expression of clock genes and the incidence and progression of cancers.In fact,the disruption of the balance of cellular metabolism,cell cycle,cell proliferation,and apoptosis due to the abnormal expression and mutation of biological clock genes can trigger the development of colorectal cancer.In addi-tion,the disrupted circadian rhythm induced by abnormal tumor cell growth can further the advancement of disease,inva-sion,and even metastasis.Our review summarizes the functions and mechanisms of prominent clock genes in the initiation and progression of colorectal cancer based on the recent studies to provide a foundation for the development of personalized chronotherapy regimes encompassing the body's innate biorhythms in standard clinical cancer treatment procedures so as to,ultimately,optimize treatment efficacy and extend patient's life expectancy.

The effects of miRNA-155-5p and the circadian clock gene Bmal1 on proliferation and aging in mouse bone marrow mesenchymal stem cells / 口腔疾病防治

Objective@#To investigate the effect of brain and muscle arant-like-1 (Bmal1) and miRNA-155-5p on the proliferation ability and aging of bone marrow mesenchymal stem cells (BMMSCs) to provide an experimental basis for elucidating the mechanism of bone senescence.@*Methods @# BMMSCs were extracted from the femur medullary cavity of 1-month-old mice, purified and cultured via the whole bone marrow mesenchymal adherent method and passed to P3. The characteristics of BMMSCs were detected by flow cytometry. BMMSCs were transfected with lentivirus to construct stable miR-155-5p and Bmal1 overexpression/interference BMMSCs. shRNA-transfected BMMSCs were identified by qRT-PCR. The proliferation activities of miR-155-5p and Bmal1 overexpression/interference BMMSCs were detected via CCK-8 assay. The apoptosis rates were measured by flow cytometry. The aging status of BMMSCs was identified with the senescence-associated β-galactosidase (SA-β-Gal) test. The expression of senescence-related genes P16 and P53 was detected by qRT-PCR.@*Results@#The shRNA-transfected BMMSCs were successfully generated. The proliferation ability decreased, and the apoptosis rates, the activity of SA-β-Gal and the relative expression levels of P53 and P16 increased when miRNA-155-5p was overexpressed. The proliferation ability increased, and the apoptosis rates, the activity of SA-β-Gal and the relative expression levels of P53 and P16 decreased when miRNA-155-5p was inhibited. The effect of Bmal1 is opposite to that of miRNA-155-5p.@*Conclusions @# The expression of Bmal1 promotes the proliferation and antiaging ability of BMMSCs, while miRNA-155-5p inhibits the proliferation and accelerates the aging of BMMSCs.

Research progress of circadian rhythm / 中国中药杂志

Circadian rhythm disorder is a common society issue caused by jet lag,shift work,sleep disruption and changes in food consumption. Light is the major factor affecting the circadian rhythm system. Disruption of the circadian rhythm system can cause damage to the body,leading to some diseases. Maintaining a normal circadian system is of great importance for good health. Ideal therapeutic effect can not only alleviate symptoms of the diseases,but also recovery the disturbed circadian rhythm to normal. The paper summarizes the modeling methods of animal circadian rhythm disorder,diseases of circadian rhythm abnormality,regulation of circadian clock genes and medicine which are related to circadian rhythm to diseases of circadian rhythm disorder.

Circadian effects of ionizing radiation on reproductive function and clock genes expression in male mouse

BACKGROUND@#Exposure to the ionizing radiation (IR) encountered outside the magnetic field of the Earth poses a persistent threat to the reproductive functions of astronauts. The potential effects of space IR on the circadian rhythms of male reproductive functions have not been well characterized so far.@*METHODS@#Here, we investigated the circadian effects of IR exposure (3 Gy X-rays) on reproductive functional markers in mouse testicular tissue and epididymis at regular intervals over a 24-h day. For each animal, epididymis was tested for sperm motility, and the testis tissue was used for daily sperm production (DSP), testosterone levels, and activities of testicular enzymes (glucose-6-phosphate dehydrogenase (G6PDH), sorbitol dehydrogenase (SDH), lactic dehydrogenase (LDH), and acid phosphatase (ACP)), and the clock genes mRNA expression such as Clock, Bmal1, Ror-α, Ror-β, or Ror-γ.@*RESULTS@#Mice exposed to IR exhibited a disruption in circadian rhythms of reproductive markers, as indicated by decreased sperm motility, increased daily sperm production (DSP), and reduced activities of testis enzymes such as G6PDH, SDH, LDH, and ACP. Moreover, IR exposure also decreased mRNA expression of five clock genes (Clock, Bmal1, Ror-α, Ror-β, or Ror-γ) in testis, with alteration in the rhythm parameters.@*CONCLUSION@#These findings suggested potential health effects of IR exposure on reproductive functions of male astronauts, in terms of both the daily overall level as well as the circadian rhythmicity.

Nutrición y sueño / Nutrition and sleep

La nutrición correcta es relevante para un buen sueño, conocidos son los beneficios del sueño en la fisiología metabólica y cognitiva; su papel en la genética y la inmunidad a lo largo de la vida. Se presenta a continuación cómo la nutrición podría contribuir por varios factores, tanto en los genes reloj y su papel en el ritmo circadiano y hormonal, así como en la formación de neurotransmisores relacionados con el sueño. También se menciona su papel en los cronotipos y varios alimentos que mejorarían nuestro sueño. Concluimos que es importante como medida de salud pública en nuestros pacientes en un contexto de vida agitada, con altas tasas de exceso de desnutrición, y evitando la automedicación con hipnóticos para lograr un buen sueño. Palabras clave: Crononutrición, genes del reloj, cronotipos, nutrientes, sueño.

The right nutrition is relevant for good sleep, the benefits of sleep on metabolic and cognitive physiology are well known, as is their role in genetics and immunity throughout life. We explore how nutrition could contribute through several factors, both in the clock genes and their role in circadian and hormonal rhythm, as well as through the formation of sleep-related neurotransmitters. Its role in chronotypes and various foods that would improve our sleep is also mentioned. We conclude that it is important to intervene nutrition as a public health measure in our patients, who have a hectic life context, with high rates of excess malnutrition, and thus avoiding self-medication with hypnotics to achieve a good sleep. Keywords: Timeline, clock genes, chronotypes, nutrients, sleep

Regulação molecular do ritmo circadiano e transtornos psiquiátricos: uma revisão sistemática / Molecular regulation of circadian rhythm and psychiatric disorders: a systematic review

RESUMO Objetivo O artigo possui como objetivo investigar os genes relógio que estão mais associados com os transtornos psiquiátricos, as funções e localizações desses genes, assim como investigar o principal transtorno, método e modelo considerados nas análises. O trabalho busca resumir os achados e discutir o impacto dessas pesquisas no conhecimento científico. Métodos Esta revisão utilizou-se de uma metodologia sistemática (Prospero; ID 152031) e seguiu as diretrizes PRISMA. A busca dos estudos foi realizada nas bases de dados PubMed/MEDLINE e Scientific Eletronic Library Online e foram utilizados os termos do Medical Subject Headings Terms . Foram selecionados estudos quantitativos com resultados conclusivos referentes à associação de transtornos psiquiátricos com a regulação molecular do ritmo circadiano. As informações úteis foram extraídas e utilizadas para a elaboração de gráficos e tabelas. Resultados Foram incluídos 24 artigos em nosso estudo. Observou-se que o transtorno bipolar consistiu no transtorno psiquiátrico mais abordado (40% dos estudos); a nacionalidade polonesa dos participantes também se destacou em 39% dos trabalhos. Adicionalmente, o gene PER foi o mais estudado (25%) e o córtex cerebral foi a principal região em que os genes relógio avaliados se expressam (34%). A PCR comum mostrou ser o método mais utilizado (38%) e o metabolismo da serotonina mostrou ser a principal função desempenhada pelos produtos gênicos (16%). Conclusões Em conjunto, os resultados sugerem que o transtorno bipolar consiste no distúrbio psiquiátrico mais prevalente entre as pesquisas relacionadas aos genes circadianos, expressos principalmente no córtex cerebral de humanos, em especial o gene PER .

ABSTRACT Objective The article aims to investigate the clock genes that are most associated with psychiatric disorders, the functions, and locations of these genes, as well as to investigate the main disorder, method and model in the analyzes. The paper seeks to summarize the findings and discuss the impact of this research on scientific knowledge. Methods This review used a systematic methodology (Prospero; ID 152031) and followed the PRISMA guidelines. The studies were searched in the PubMed/MEDLINE and Scientific Electronic Library Online databases and the terms of the Medical Subject Headings Terms were used. Quantitative studies with conclusive results regarding the association of psychiatric disorders with the molecular regulation of circadian rhythm were selected. The useful information was extracted and used for the elaboration of graphs and tables. Results We included 24 articles in our study. Bipolar disorder was the most commonly addressed psychiatric disorder (40% of studies); The participants' Polish nationality also stood out in 39% of the works. Additionally, the PER gene was the most studied (25%) and the cerebral cortex was the main region in which the evaluated clock genes express themselves (34%). Finally, common PCR was the most used method (38%) and serotonin metabolism was the main function performed by gene products (16%). Conclusions Taken together, the results suggest that bipolar disorder is the most prevalent psychiatric disorder among research related to circadian genes, expressed mainly in the cerebral cortex of humans, especially the PER gene.

Feedback loops in circadian clocks of Drosophila and mammals

Circadian rhythm is 24-hour cycle rhythmicity in organisms, which is endogenous, entrained by environmentalcues, and temperature-compensated. Circadian rhythm is driven by circadian clock, which is present in allthe cells and tissues of the body. Small ventral lateral neurons located in the lateral brain in Drosophilaand suprachiasmatic nucleus in mammals are the central oscillators which regulate all the peripheral clockspresent throughout the body. The circadian rhythm is maintained by a conserved transcriptional–translationalautoregulatory loop, which generates oscillations in the expression of clock genes. Here, this review focuses onthe interconnected feedback loops present in Drosophila and mammals.

Effects of hypnotic active components of Cnidii Fructus on expression of hippocampal Clock genes and amino acid neurotransmitters in PCPA insomnia rats / 中草药

Objective To study the hypnotic mechanism of Cnidii Fructus hypnotic active constituent (SCZ) on the expression of clock genes and hippocampal neurotransmitters in insomnia rats. Methods The insomnia model was established by intraperitoneal injection of para-chlorophenylalanine (PCPA). SCZ at low (25 g/kg), medium (50 g/kg), and high (100 g/kg) conentrations were ig administrated respectively at the same time with diazepam as positive group, intragastric administration of PCPA was performed in insomnia rats for three days, The expression levels of Clock, Bmal1, Cry1, Cry2, Per1, Per2, and Per3 were detected by real-time PCR. The expression levels of γ-aminobutyric acid (GABA) and glutamic acid (Glu) in hippocampus dentate gyrus were detected by immunohistochemistry. The changes of contents of GABA and Glu were determinated by immunohistochemistry and high performance liquid chromatography. Results The results of immunohistochemistry showed that the expression of GABA in the dentate gyrus of the hippocampus of rats in the model group was significantly reduced compared with the control group, and the expression level of Glu was significantly increased (P < 0.05, 0.01). Compared with the model group, the expression level of GABA in SCZ medium and high dose group was significantly increased, and Glu expression was reduced significantly (P < 0.01). HPLC results showed that the GABA expression level in the hippocampus of the model group was significantly decreased compared with the control group, and the expression level of Glu was significantly increased (P < 0.05, 0.01). Compared with the model group, the expression level of Glu in hippocampus of rats in SCZ medium and high dose group was significantly decreased (P < 0.05), and the expression of GABA in rats with high and low doses of SCZ was significantly increased (P < 0.01). The results of Clock gene expression test showed that the expression of Clock and Bmal1 gene in the model group was significantly increased (P < 0.05) compared with the control group, and the expression levels of Cry1, Per1, and Per2 genes were significantly decreased (P < 0.05, 0.01). Compared with the model group, the expression of Clock and Bmal1 gene in the SCZ medium dose group was significantly decreased (P < 0.01); The expression levels of Cry1, Per1, and Per2 in the SCZ high dose group were significantly increased (P < 0.05, 0.01). The Per1 gene expression in the SCZ low-dose group was significantly increased (P < 0.01). Conclusion Cnidii Fructus hypnotic active components can increase the expression of Cry1, Per1, and Per2 gene by reducing the hypnosis of hippocampal Clock and Bmal1 expression. The increased expression of the inhibitory neurotransmitter GABA and the decreased expression of excitatory neurotransmitter Glu can inhibit the occurrence and development of insomnia, which can regulate the sleep-wake cycle for clinical treatment of insomnia.

Circadian system:new target for the treatment of Parkinson's disease / 中华行为医学与脑科学杂志

It was widely believed that disorders of circadian system were caused by neurodegenera-tive diseases. With the deepening of research,many scholars believed that disorders of circadian system may affect the occurrence and development of neurodegenerative diseases such as Parkinson's disease. 'Parkinson 's disease' and 'Circadian rhythm' were used as the key words of retrieval performance in the databases such as Pubmed,CNKI,Wanfang and so on,and the papers which were closely related with the theme were select-ed. The epidemiology,etiology and pathogenesis,clinical manifestations and the role of circadian system reg-ulation in PD were reviewed. The results show that the disorders of circadian system could be regulated by bright light therapy,melatonin and stem cell therapy,music therapy,and deep brain stimulation. Based on the theory of time medicine,combining the regulation of circadian system with the classical treatment of PD may provide a new breakthrough point for PD treatment. The disorders of circadian system is expected to be-come a new target for PD therapy.

Sleep-wake rhythm after extracorporeal circulation in New Zealand rabbits / 中南大学学报(医学版)

Objective:To evaluate the change of sleep-wake rhythm after extracorporeal circulation (ECC) in New Zealand rabbits,and to explore the role of clock genes in sleep-wake rhythm disorder by ECC.Methods:A total of 54 New Zealand rabbits were randomly divided into 3 groups:a normal group (Group N),a sham group (Group S) and a model group (Group ECC).Electrocorticogram (ECOG),electroophthalmogram (EOG) and electromyogram (EMG) were respectively recorded by multipurpose EEG recorder,and the sleep-wake rhythm was also recorded.The mRNA and protein expressions of period1 (Per1) and cryptochrome1 (Cry1) were detected by semiquantitative reverse transcriptase PCR (RT-PCR) and Western blot in pineal gland of rabbits.The differences between the 3 groups were compared.Results:1) Compared with the Group N and Group S at 24,48 h respectively,the total amount of sleep (TAS),light time,slow wave sleep (SWS) in the Group ECC at 24,48 h were significantly reduced (all P＜0.05),and the proportion of light sleep increased (all P＜0.05),the proportion of SWS decreased (all P＜0.05);2) Compared with the Group N and Group S,the expression of Per1 mRNA in the Group ECC at 24,48 h and Cry1 mRNA at 24 h significantly increased (all P＜0.05);3) Compared with the Group N and Group S,the expression of Perl protein in the Group ECC at 48 h and Cry1 protein at 24 h significantly increased (all P＜0.05);4) In the Group ECC,the sleepwake rhythm disorder and clock genes expression were ameliorated at 72 h after surgery.Conclusion:ECC can cause sleep-wake rhythm disorder in New Zealand rabbits,which may be related to the abnormal expression of Per1 and Cry1,and their transcription proteins.

Electroconvulsive Seizure Alters the Expression and Daily Oscillation of Circadian Genes in the Rat Frontal Cortex

OBJECTIVE: Electroconvulsive therapy (ECT) is the most effective treatment for mood disorders. Accumulating evidence has suggested the important role of circadian genes in mood disorders. However, the effects of ECT on circadian genes have not been systemically investigated. METHODS: We examined the expression and daily oscillation of major circadian genes in the rat frontal cortex after electroconvulsive seizure (ECS). RESULTS: Firstly, mRNA and protein level were investigated at 24 hr after single ECS (E1X) and repeated ECS treatements for 10 days (E10X), which showed more remarkable changes after E10X than E1X. mRNA expression of Rorα, Bmal1, Clock, Per1, and Cry1 was decreased, while Rev-erbα expression was increased at 24 hr after E10X compared to sham. The proteins showed similar pattern of changes. Next, the effects on oscillation and rhythm properties (mesor, amplitude, and acrophase) were examined, which also showed more prominent changes after E10X than E1X. After E10X, mesor of Rorα, Bmal1, and Cry1 was reduced, and that of Rev-erbα was increased. Five genes, Rev-erbα, Bmal1, Per1, Per2, and Cry2, showed earlier acrophase after E10X. CONCLUSION: The findings suggest that repeated ECS induces reduced expression and phase advance of major circadian genes in the in vivo rat frontal cortex.

Effect of continuous sleep deprivation on liver circadian clock gene expression and alteration of liver bio-marker levels in rats / 军事医学

Objective To investigate the effect of 36 h continuous sleep deprivation(SD) on circadian clock gene expression in the rat liver and kidney and the alteration of urine biomarker levels.Methods Twelve rats were randomly divided into control group and SD group.An SD device was used to deprive the rats of sleep.After 36 h continuous SD, the abdominal cavity was exposed to obtain livers and kidneys, and RT-PCR and Western blotting were used to detect expression of clock genes.Then,the pelvic cavity was exposed to obtain urine, and the changes in bio-marker total bile acids(TBA) were tested with ELISA.Results Compared with the control group, the mRNA level of liver clock and bmal1 was obviously reduced in the SD-treated rats (P<0.05).However, no obvious change was found in the samples from the kidney.Sharp down-regulation of CLOCK and BMAL1 protein expression was also observed in the rat liver after SD treatment.Urine TBA content in SD treated rats was raised obviously (P<0.001), compared with control.Conclusion Thirty-six hours of continuous SD could result in deregulation of circadian clock gene and cholesterol metabolism disorder in the rat liver.TBA might be used as a noninvasive biomarker of liver injury under SD stress conditions.

Disturbances of circadian rhythm of blood pressure and local cardiac clock genes in nephrotic rats / 中华肾脏病杂志

Objective To observe the circadian blood pressure (BP) rhythms and the phase of heart circadian gene expression in adriamycin (ADR)-induced nephropathy rats,thus exploring the effect of circadian systems on circadian BP variation in nephrotic rats.Methods Sprague-Dawley (SD) male rats (8 weeks) were housed in a 12∶12 hour light/dark cycle in two weeks,and randomly divided into ADR group and control group.ADR rats were injected 6.5 mg/kg adriamycin via vein to establish nephrotic rats model two weeks later,while control rats were injected the equal volume of saline.Five rats in each group were implanted with the radio-telemetry into abdominal aortic.After seven days,systolic blood pressure (SBP),diastolic blood pressure (DBP),mean arterial pressure (MAP) and heart rate (HR) were recorded every one minute during 72 hours via radio-telemetry.Three rats in each group were sacrificed in six time points (zeitgeber time=02:00,06:00,10:00,14:00,18:00,22:00) to get the blood sample and heart tissue,respectively.The mRNA expressions of core clock gene CLOCK,BMAL1,Per1,Per2,Cry1 and Cry2 in heart issue were evaluated by the real-time quantitative PCR.The plasma levels of renin activity angiotensin Ⅱ and aldosterone were measured by radioimmunoassay.All the data were analyzed by a partial Fourier analysis and stepwise regression.Results (1) There was no significant difference in 24 h average of SBP,DBP and MAP between two groups.In control group,there was higher SBP (3.22 mmHg),DBP (1.16 mmHg) and MAP (3.19 mmHg) in dark period than those in light period,only SBP and MAP showing statistical difference (all P ＜ 0.05).However,SBP,DBP and MAP had no significant difference between dark and light in ADR group (all P ＞ 0.05).(2) Control rats had (8.0+24.0) h rhythm of SBP,and their DBP,MAP and HR appeared 24.0-hour normal circadian pattern (all P ＜ 0.05).In ADR group,the rhythm of SBP completely disappeared.And their DBP and MAP remained 24.0 h circadian rhythm,but the peak time advanced 1.5 h to 3.0 h compared with SD rats.(3) In SD controls,daily rhythms period of the core clock genes (CLOCK,BMAL1,Cry1,Cry2,Per1 and Per2) mRNA expression in the heart were (4.8+ 12.0) h,24.0 h,12.0 h,(12.0+24.0) h,(4.8+12.0) h and 12.0 h (all P ＜ 0.05),respectively.In ADR rats,the rhythm of CLOCK,BMAL1,Cry2,Per1 and Per2 mRNA completely disappeared (all P ＞ 0.05).The circadian rhythm of Cry1 mRNA remained,but the period was changed from 12.0 h to (4.8+6.0) h.(4) The plasma renin and aldosterone concentration presented 12.0 h and 24.0 h daily rhythms in SD rats (all P ＜ 0.05).These diurnal changes however completely disappeared in ADR rats (all P ＞ 0.05).Conclusions ADR nephrotic rats lose the circadian rhythm of BP with the disturbances of cardiac circadian clock system.The disrupted diurnal rhythm of the core clock genes (CLOCK,BMAL1,Cry2,Per1 and Per2) mRNA expression in the heart may regulate the pathological circadian rhythms of heart tissue,which is involved with disturbances of circadian rhythm of BP.

Atuação das proteínas do relógio na senescência reprodutiva de ratas Wistar / Clock protein action in the senescence reproductive of female Wistar rats

O envelhecimento é considerado processo multidimensional no qual fatores ambientais podem proteger ou, inversamente, agravar seus sinais, de maneira não linear, nos processos fisiológicos e neurocomportamentais. Durante este processo, os ritmos circadianos são interrompidos ou fragmentados com dissociação consequente dos ritmos circadianos do indivíduo e disfunções relacionadas ao relógio circadiano contribuem para o envelhecimento e para patologias a ele relacionadas. O objetivo deste estudo foi averiguar possível alteração temporal do sistema CLOCK no eixo HPG e a relação com às alterações hormonais que caracterizam a periestropausa. Foram utilizadas fêmeas adultas com ciclo estral regular (CD) na fase do diestro e fêmeas senis com ciclo estral irregular e persistência da fase do diestro (IDP). Para análises de expressão gênica dos clock genes Per2, Rev-erbα e Bmal1 no eixo HPG, foram utilizados punchs das regiões do NSQ, onde também foi analisado RNAm de AVP, APO e HMB destes animais, além da adenohipófise e ovários dos quais se extraiu o RNA para confecção do cDNA e realização de qPCR. A determinação da atividade neuronal vasopressinérgica no NSQ foi realizada por imunoistoquíca com dupla marcação para cFos e AVP em tecido previamente fixado com paraformaldeído. A concentração plasmática de gonadotrofinas foi determinada por radioimunoensaio. De modo geral, os animais IDP revelaram alterações no perfil de expressão gênica durante o fotoperíodo, com redução de amplitude, deslocamento/desalinhamento de fase e ausência de antifase. O NSQ de animais IDP apresentou menor expressão de Rev-erbα e maior expressão de RNAm para AVP em relação ao grupo CD. A quantificação relativa de Bmal1 foi semelhante em ambos os grupos e não houve diferenças entre grupos na expressão de Per2. Na APO, animais IDP apresentaram maior expressão de Per2 e menor quantidade de RNAm para Rev-erbα. No HMB observou-se menor expressão para Per2 e Rev-erbα e maior expressão de Bmal1 nas fêmeas IDP. Per2 e Bmal1 na adenohipófise tiveram menor expressão que o gene Rev-erbα no grupo senil e o ovário destes animais revelou maior expressão para Per2 e Rev-erbα, em comparação com os animais CD. As concentrações plasmáticas de FSH foram maiores nas fêmeas com ciclo irregular (2,05 ± 0,44 ng/mL), principalmente durante a fase clara, assim como o LH (0,24 ± 0,07 ng/mL), cujos maiores valores foram encontrados durante a fase escura e com perfil semelhante ao RNAm de AVP. As imunomarcações revelaram alta atividade vasopressinérgica na porção dorsomedial do NSQ das fêmeas IDP. Juntos estes dados permitem concluir que há desarranjo na expressão temporal dos genes Per2, Rev-erbα, Bmal1 que compõem a maquinaria molecular do relógio circadiano, bem como de RNAm para AVP no NSQ, de fêmeas Wistar na periestropausa. Além disso, a maior atividade neuronal vasopressinérgica e a ausência de oscilação de Rev-erbα e Bmal1 no NSQ destes animais, comprometem a correta comunicação do relógio central do NSQ com o eixo HPG, inviabilizando a manutenção da fertilidade feminina e contribuindo para a senescência reprodutiva(AU)

Aging is considered a multidimensional process in which environmental factors can protect or, conversely, aggravate its signals, non-linearly, in physiological and neurobehavioral processes. During this process, circadian rhythms are disrupted or fragmented with consequent dissociation of the individual's circadian rhythms and circadian clock-related dysfunctions contribute to aging and related pathologies. The objective of this study was to investigate possible temporal alteration of the CLOCK system in the HPG axis and the relation with the hormonal changes that characterize periestropause. Adult females with regular estrus cycle in the diestrous phase (RD) and old females with irregular estrous cycle and persistent diestrous phase (IPD). For analyzes of the gene expression of the genes Per2, Rev-erbα and Bmal1 in the HPG axis, punchs from the NSQ regions were used, where AVP, POA and MBH RNAm from these animals were also analyzed, as well as the adenohypophysis and ovaries from which they were extracted the RNA for cDNA production and qPCR performance. The determination of the vasopressinergic neuronal activity in the NSQ was performed by immunohistochemical with double labeling for cFos/AVP in tissue previously fixed with paraformaldehyde. The plasma concentration of gonadotrophins was determined by radioimmunoassay. In general, the IPD animals show alterations in the gene expression profile during the period analyzed, with amplitude reduction, phase shift / misalignment and absence of antiphase. The NSQ of IPD animals presented lower expression of Rev-erbα and higher RNAm expression for AVP than RD group. The relative quantification of Bmal1 was similar in both groups and there were no differences between groups in the expression of Per2. In PAO, IPD animals showed higher expression of Per2 and less amount of RNAm for Rev-erbα. MBH showed lower expression for Per2 and Rev-erbα and higher Bmal1 expression in IPD females. Per2 and Bmal1 in the adenohypophysis had lower expression than the Rev-erbα gene in the old group and the ovary of these animals showed higher expression for Per2 and Rev-erbα, in related to to the RD animals. Plasma concentrations of FSH were higher in females with irregular cycle (2.05 ± 0.44 ng / mL), mainly during the light phase, as well as LH (0.24 ± 0.07 ng / mL) whose values were found during the dark phase and with a profile similar to AVP RNAm. Immunolabeling demonstrated high vasopressinergic activity in the dorsomedial portion of the NSQ of the IPD females. Together these data allow us to conclude that there is a breakdown in the temporal expression of the Per2, Rev-erbα, Bmal1 genes that make up the molecular machinery of the circadian clock, as well as RNAm for AVP in NSQ of Wistar females in peri-masterpause. In addition, the increased vasopressinergic neuronal activity and the absence of Rev-erbα and Bmal1 oscillation in the NSQ of these animals compromise the correct communication of the central clock of the NSQ with the HPG axis, making it impossible to maintain female fertility and contributing to reproductive senescence(AU)

Effects of simulated microgravity on circadian rhythm of caudal arterial pressure and heart rate in rats and their underlying mechanism / 解放军医学杂志

Objective To explore the effects of simulated microgravity on the circadian rhythm of rats' caudal arterial pressure and heart rate, and their underlying mechanism. Methods Eighteen male SD rats (aged 8 weeks) were randomly assigned to control (CON) and tail suspension (SUS) group (9 each). Rats with tail suspension for 28 days were adopted as the animal model to simulate microgravity. Caudal arterial pressure and heart rate of rats were measured every 3 hours. The circadian difference of abdominal aorta contraction was measured by aortic ring test. Western blotting was performed to determine and compare the protein expression level of clock genes such as Per2 (Period2), Bmal1 (Aryl hydrocarbon receptor nuclear translocatorlike) and dbp (D element binding protein) in suprachiasmatic nucleus (SCN) and abdominal aorta of rats in CON and SUS group at different time points. Results Compared with CON group, the caudal arterial pressure, both systolic and diastolic pressure, decreased significantly and the diurnal variability disappeared, meanwhile the heart rate increased obviously and also the diurnal variability disappeared in rats of SUS group. Compared with CON group, the contraction reactivity of abdominal aorta decreased with disappearence of the diurnal variability, and also the clock genes expression in SCN and abdominal aorta showed no diurnal variability in rats of SUS group. Conclusion Simulated microgravity may lead to circadian rhythm disorders in rats' cardiovascular system, which may be associated with the changes of the clock genes expression.

Tissue-specific Changes of Clock DNA Promoter Methylation with Aging / 中国康复理论与实践

Objective To investigate the role of the clock gene promoter methylation in aging. Methods C57BL mice of 4-(young, n=9) and 20-(old, n=10) month-old were determined the promoter methylation level of clock genes (Per1/2, Bmal1/2, Cry1/2, Clock, Npas2) in the stomach, spleen, vascular, kidney and striatum with methylation-specific polymerase chain reaction (MSP). Results The incidence of promoter methylation of Cry1, Bmal2 and Npas2 in spleen increased in old mice (P<0.05), while the promoter methylation of Per1 in stom-ach decreased (P<0.05), and the promoter methylation of Bmal1 in vascular increased (P<0.05). Conclusion Promoter methylation of some clock genes is involved in process of aging in a tissue-specific way.

Tissue-specific Changes of Clock DNA Promoter Methylation with Aging / 中国康复理论与实践

@#Objective To investigate the role of the clock gene promoter methylation in aging. Methods C57BL mice of 4- (young, n=9) and 20- (old, n=10) month-old were determined the promoter methylation level of clock genes (Per1/2, Bmal1/2, Cry1/2, Clock, Npas2) in the stomach, spleen, vascular, kidney and striatum with methylation-specific polymerase chain reaction (MSP). Results The incidence of promoter methylation of Cry1, Bmal2 and Npas2 in spleen increased in old mice (P<0.05), while the promoter methylation of Per1 in stomach decreased (P<0.05), and the promoter methylation of Bmal1 in vascular increased (P<0.05). Conclusion Promoter methylation of some clock genes is involved in process of aging in a tissue-specific way.