Roles of the Circadian Clock in Ovarian Physiology and Pathology / 中国生物化学与分子生物学报

The circadian rhythm of mammals is a physiological phenomena that is about 24 hours produced by genetically encoded molecular clocks, making the physiological process of the body coordinated with the changes of the external environment, and it is a manifestation of adaptation to the environment. In mammals, reproductive physiology is regulated by the circadian clock. The expression of circadian clock genes has been observed in each tissue of the hypothalamic-pituitary-ovarian (HPO) axis, and the biological clock at all levels coordinates and synchronizes with each other to maintain normal reproductive behavior. The production, maintenance, and regulation of circadian rhythms depend on a chain of transcription-translation feedback loops (TTLs), which determine the cycle and amplitude of gene expression in each tissue of the HPO axis. The circadian clock of the ovary is regulated by theneuroendocrine regulation of suprachiasmatic nucleus of the hypothalamus, but it is autonomous. Circadian rhythm disruption caused by environmental factors can seriously impair female fertility and lead to a range of related ovarian diseases. In addition, the circadian clock is also closely related to ovarianaging. Based on existing research, this paper focuses on the mechanism of the circadian clock in ovarian follicular development, ovulation and steroid generation, as well as the latest research progress on the relationship between the circadian clock and ovarian aging. In addition, several common ovarian diseases with decreased fertility due to circadian clock disorders are described.

Dual Roles of Lipid in Oocyte Development / 中国生物化学与分子生物学报

Oocytes are the germ cells of female animals, which determine the reproductive ability of female animals. A large amount of lipids are present in oocytes, which are found in lipid droplets mostly in the form of triglycerides. The size, color and distribution pattern of lipid droplets are associated with the developmental ability of oocytes. Triglycerides could be lipolyzed into fatty acids in oocytes. The fatty acid β-oxidation is an important energy source for the development of oocytes and early embryos. However, excessive lipid deposition would increase levels of reactive oxygen species (ROS), resulting in the dysfunction of mitochondria and endoplasmic reticulum, eventually impairing the subsequent oocyte development. By summarizing the positive and negative effects of lipids on oocyte development, this review shows the dual roles of lipids in oocyte development, and discusses the effects of lipids on oocyte development.

Effects of N-Oleoylglycine and Oleate on Mitochondrial UCP1-independent Thermogenesis / 中国生物化学与分子生物学报

Besides UCP1-dependent thermogenesis pathways, UCP1-independent thermogenesis pathways also could increase heat production in adipose tissue to combat obesity. N-Acyl amino acids (NAAs) have been suggested as novel endogenous uncouplers to induce mitochondria UCP1-independent thermogenesis in adipose tissue. Here, we use mouse skeletal muscle C2C12 cells which lack of UCP1 as UCP1 negative cell models. Comparing with its corresponding common fatty acid—oleate, one of the NAAs—N-Oleoylglycine (NOGly), which is highly expressed in the plasma of HFD mice, is selected to study their effects and mechanisms on mitochondrial thermogenesis. We found that 60 μmol / L oleate could induce mitochondrial oxidative phosphorylation protein levels, as well as increase mitochondria thermogenesis-related genes (COX8b, DIO2, UCP3) expression (P < 0. 05) . However, 60 μmol / L NOGly damaged the production and oxidative phosphorylation of mitochondria, significantly down-regulated expression of thermogenic genes (PGC1a, COX8b, COX2, DIO2, UQCRFS1and UCP3) (P< 0. 01), induced the production of reactive oxygen species (ROS) in the mitochondria, and enhanced the oxidative stress in cells. Our study found that oleate can induce UCP1-independent thermogenesis under 60 μmol / L addition dose, whereas NOGly does not due to the induction of oxidative stress in cells.

Effect of emodin on proliferation and differentiation of rat preadipocytes / 中国中药杂志

<p><b>OBJECTIVE</b>To study the effect of emodin (EMO) on the proliferation and differentiation of rat preadipocytes.</p><p><b>METHOD</b>Separating and culturing rat preadipocytes, grouping the wells that preadipocytes were growing according to certain concentration such as 0, 5, 10, 20, 40, 80, 160 micromol x L(-1) randomly, MTT spectrophotometry and flow cytometry (FCM) were adopted to determine the effect of EMO on proliferation of rat preadipocytes. The accumulation of TG (triglyceride) in adipocytes was assayed by oil red O staining, and the morphological changes of the adipocytes were determined by morphology observation.</p><p><b>RESULT</b>EMO in the range of 20-160 micromol x L(-1) could inhibit the proliferation and differentiation of preadipocytes in a dose and time dependent manner, and induce apoptosis of preadipocytes in a certain degree.</p><p><b>CONCLUSION</b>EMO should have a potential to serve as a fat-reducing drug.</p>

Cloning and sequence analysis of SOCS-2 gene in pig / 生物工程学报

Total RNA was isolated from kidney of BaMei pig, a local strain of Chinese pig, and then the cDNA sequence of SOCS-2 gene was cloned by RT-PCR (GenBank accepted number is EF121242). Then the cloned SOCS-2 gene was inserted into PMD19-T vector by T/A cloning, transformed into DH-5alpha, tested by PCR and sequenced. The data show that the homology of the cloned porcine SOCS-2, including 822 bp, is more than 93% and that of the deduced amino acid sequence is 89% when compared with human, rat and mice. And the molecular weight of SOCS-2 protein is about 22.25 kD and PI is 8.03. The cloning of SOCS-2 gene is useful for the further research on the molecular mechanism by which regulating growth and development of organism.

Study on the characteristics of tissue expression of hormone sensitive lipase and triacylglycerol hydrolase in pigs / 生物工程学报

The specific expression of TGH and HSL genes in different tissues of Bamei pig was investigated by RT-PCR and Western blot in this study. The result of RT-PCR showed that the expression of HSL could be detected in all these seven tissues examined, and which was higher expressed in fat, lower in heart, liver, lung, spleen and kidney. Expression of TGH gene could also be detected in seven tissues, and higher in liver and fat, lower in heart and kidney and lowest in spleen and lung. The result of Western blot showed that, HSL gene was highest expressed in epiploica fat and subcutaneous fat, higher in other tissues, but couldn' t be detected in kidney. Expression of TGH was detected in epiploica fat, subcutaneous fat, liver, lung and spleen, and highest in fat and liver, but it hadn't be found in heart and kidney. These results suggested that both HSL and TGH could be regulated by post-transcriptional, and their function was involved in different tissues.

Effects of resveratrol on pig primary preadipocytes proliferation, differentiation and transcription expression of Sirt1 gene / 生物工程学报

1 approximately 3 days old Piglet's primary preadipocytes in vitro were cultured and treated with 0micromol/L (control group), 10microlmol/L (lower dose group), 20micromol/L(middle dose group) and 50micromol/L, 100micromol/L (higher dose group) RES. Cell proliferation and viability were analyzed by MTT assay. The degree of differentiation and adipogenesis were measured by Oil Red O staining extraction assay and the expression of Sirt1 (sirtuin) mRNA were detected by RT-PCR. The results showed the optical density (OD) of MTT and Oil Red O staining were all decreased, especially treated by 50micromol/L, 100micromol/L RES at 72h and 96h (P < 0.01); the ratio of OD of the expression of Sirt1 mRNA to that of beta-actin mRNA were increased after treated by 100micromol/L RES (P < 0.01). RES can inhibit proliferation and differentiation of pig preadipocytes in certain degree. Higher dose of RES can markedly decrease adipogenesis and prevent preadipocytes differentiation into adipocytes, which may be in part associated with its effect on increasing the expression of Sirt1 mRNA.

Effects of baicalein on the proliferation and differentiation of pig preadipocyte / 生物工程学报

To investigate the effects of Baicalein (BAI) on the proliferation and differentiation of pig preadipocytes, and elucidate its potential mechanism. Primary preadipocytes of pig were cultured in vitro. The morphologic changes of preadipocytes differentiation were observed by Oil Red O staining. Status of cell proliferation was detected by MTT assay. The degree of adipogenesis and differentiation were measured by Oil Red O staining extraction assay. The activity of fatty acid synthase (FAS) was detected by spectrophotometry. The mRNA expression of special peroxisome proliferation activated receptor-gamma2 gene (PPARgamma2) was detected by reverse transcriptase polymerase chain reaction (RT-PCR). When preadipocytes differentiated into adipocytes, the preadipocytes were changed from shuttle shape to oval or round, in which big and small lipid droplets were filled. The proliferation of preadipocytes was inhibited by the treatment of 160-640 micromol/L BAI (P < 0.05). The mRNA expression of PPARgamma2 and FAS activity and the differentiation of preadipocytes was repressed by 40-320 micromol/L BAI treatment (P < 0.05). It is concluded that the proliferation and differentiation of preadipocytes is inhibited by BAI in some degree. The effect of BAI on differentiation of preadipocytes may be resulted from inhibiting the mRNA expression of PPARgamma2 and reducing FAS activity.

Effects of docosahexaenoic acid on rat adipocytes proliferation and differentiation / 生物工程学报

To investigate effects of docosahexaenoic acid (DHA) on proliferation and differentiation of rat adipocytes and to elucidate its potential mechanism, rat's primary preadipocytes in vitro were cultured. Treated adipocytes with 0 micromol/L (control group), 40 micromol/L (lower dose group) and 160 micromol/L (higher dose group) DHA. Cell living rations and proliferation were analyzed by trypan blue exclusion and MTT assay. The degree of adipogenesis and differentiation were measured by Oil Red O staining extraction assay and the expression of peroxisome proliferation activated receptor-gamma2 (PPARgamma2) mRNA were detected by reverse transcriptase-polymerase chain reaction (RT-PCR). It was demonstrated that cells living ration and the optical density (OD) of MTT were all decreased, especially treated by 160 micromol/L DHA at 60 (72 hours (P < 0.05). The OD of Oil Red O staining and the expression of PPARgamma2 mRNA were all decreased after treated by 160 micromol/L DHA (P < 0.01). It can be concluded that DHA can inhibite proliferation and differentiation of adipocytes in some degree. Higher dose of DHA can markedly decrease adipogenesis and prevent differentiation of adipocytes, which may be in part associated with its effect on decreasing the expression of PPARgamma2 mRNA.