Toxic Effects of Tetrabromobisphenol A on Thyroid Hormones in SD Rats and the Derived-reference Dose

The present study determined the thyroid hormone interference of tetrabromobisphenol A （TBBPA） in Sprague-Dawley （SD） rats, and the derived-reference dose （RfD） of different endpoint effects on mammals based on experimental results and data collection. Based on repeated exposure toxicity tests on mammals and extensive research, the present study used BMDS240 Software to derive a benchmark dose, and analyzed the accuracy and uncertainty, and similarity with other studies. Test results on triiodothyronine （T3）, thyroxine （T4）, and thyroid stimulating hormone （TSH） demonstrated that all the indicators presented a non-monotonous dose-effect relationship clearly, except TSH in male rats exposed to 0-1000 mg/kg BW per day. Therefore, RfDs were derived from different critical effects. In summary, RfD for mammals in the present study was found to be 0.6 mg/kg per day.

Effects of Polygonatum odoratum Polysaccharide on Reproductive Hormones in Male Rats Fed a High-fat Diet

[Objectives]This study was conducted to investigate the effects of Polygonatum odoratum polysaccharide(POP)on organ relative weights and reproductive hormone levels in male rats fed a high-fat diet.[Methods]Thirty healthy male Sprague-Dawley(SD)rats were randomly divided into two groups according to their body weight:10 in normal control group(Group NC,n=10)and 20 in experimental group(n=20).The rats in experimental group were fed a high-fat diet for eight weeks before they were further randomly divided into two groups:high fat group(Group HF)and high fat+400 mg/(kg·d)POP group(Group HF+POP).In Group HF+POP,the rats were administered with POP for another six weeks,before their blood plasma was collected,and the relative weights of their testis and epididymis were calculated.The plasma levels of testosterone(T),estrogen(E2),follicle-stimulating hormone(FSH),cortisol(C)and luteinizing hormone(LH)were measured by radioimmunoassay,and the plasma levels of sex hormone-binding globulin(SHBG)and insulin-like growth factor-1(IGF-1)were determined by enzyme-linked immunosorbent assay.[Results]Compared with Group HF,POP could effectively inhibit rat obesity caused by high-fat diets,increase the relative weights of their testis and epididymis,plasma levels of LH,E2,FSH,T,SHBG and IGF-1,and reduce the plasma level of E2.[Conclusions]Polygonatum odoratum polysaccharide(POP)is able to effectively regulate the level of reproductive hormones in high-fat diet fed rats,and helps to protect their reproductive function.

Effects of Polygonatum sibiricum Polysaccharide (PSP) on Inflammatory Factors in Rats Fed on High-fat Diet

[Objectives]This study was conducted to explore the effects of Polygonatum sibiricum polysaccharide(PSP)on chronic intestinal inflammation caused by high-fat diet.[Methods]Thirty five male healthy SD rats were randomly divided into a normal control group(NC,normal diet,n=10)and a high-fat diet group(HF,high-fat diet,n=25).After 8 weeks,an obesity model was established.The HF group was randomly divided into an HF group and a PSP treatment group[PSP,300 mg/(kg·d)].After 6 weeks of intervention with PSP,rat serum was collected,and the spleen and thymus were stripped,and weighed.Serum IgG,IgM,LPS and IL-1βand IL-6 contents were detected by ELISA,and HE staining was adopted to observe the pathological changes of the colon tissue.[Results]PSP reduced the level of LPS caused by high-fat diet and the levels of inflammatory factors IL-6 and TNF-α,increased the indexes of the thymus and spleen serving as immune organs,increased IgG and IgM contents,and alleviated pathological damage to the colon tissue caused by high-fat diet.[Conclusions]This study provides a theoretical basis and experimental basis for the development of drugs for treating metabolic diseases such as obesity and inflammation.

Effects of Polygonatum sibiricum Polysaccharide on Antioxidant Capacity of the Liver in High-fat Diet Rats

[Objectives]This study was conducted to investigate the effects of Polygonatum sibiricum polysaccharide(PSP)on antioxidant function in high-fat diet obese rats.[Methods]Thirty five healthy male SD rats were selected to establish an obesity model after feeding a high-fat for 8 weeks.They were then randomly divided into a normal group(NC),a high-fat diet group(HF),and an HF+P.sibiricum polysaccharide group[HF+PSP,300 mg/(kg·d)].After 6 weeks of PSP intervention,the serum and liver of rats were collected,and the activity of aspartate transaminase(AST)and alanine aminotransferase(ALT)in serum,the enzyme activity of superoxide dismutase(SOD),catalase(CAT)and glutathione peroxidase(GSH-Px)and malondialdehyde(MDA)in liver tissue were measured.The pathological changes of liver tissue were observed by HE staining.[Results]Compared with the HF group,PSP could effectively inhibit obesity caused by high-fat diet.It reduced body weight and serum AST and ALT levels,increased the contents of T-SOD,CAT and GSH-Px in the liver,and inhibited the accumulation of MDA content,thereby reducing damage to liver cells caused by a high-fat diet.It indicated that PSP could effectively inhibit obesity in high-fat diet rats and enhance their antioxidant capacity.[Conclusions]This study provides a reference for the study of the antioxidant capacity of PSP.

PNPLA5-knockout rats induced by CRISPR/Cas9 exhibit abnormal bleeding and lipid level

Patatin-like phospholipase domain containing 5 （PNPLA5） is a neotype neutral lipase with dual activity of anabolism and catabolism in vitro and in vivo, which has a low mRNA expression level in humans and mice. PNPLA5, which is localized to lipid droplets and required for efficient autophagy by optimal initiation, has been speculated to possess triglyceride hydro- lase activity, and has been associated with low density lipoprotein cholesterol （LDL-C）. Above all, PNPLA5 is a relatively new gene, which is reported less about its biological function research, especially the function research in the rats is still blank. In this study, we examined the spatiotemporal expression profile of PNPLA5 and found that it was expressed at low levels in most organs of Sprague Dawley （SD） rats, but was present at very high levels in the skin and testes. To furth.er determine the biological function of PNPLA5 in mammals, we generated PNPLA5-knockout SD rats using the clustered regularly-interspaced short palindromic repeats （CRISPR）/Cas9 system. PNPLA5-null rats were viable, but showed a variety of phenotypic abnormalities, such as abnormal bleeding, and varied hematobiochemical parameters including increased serum total cholesterol （TC）, tdglycerides and high density lipoprotein cholesterol （HDL-C） level, and reduced LDL-C level, compared with wild-type control rats. These data are consistent with an important role for PNPLA5 in lipid metabolism, provJdJng a new target gene and animal model for treatment of cardiovascular diseases in the future.

Comparative study on the difference of obesity model induced by two kinds of high fat diet in Sprague-Dawley rats

Objective: To explore the differences of obese Sprague-Dawley(SD)rats model induced by lard oil high-fat(HF)diet or purified HF diet. Methods: SD weanling rats were randomly divided into three groups: D1 group,where rats were fed by lard oil HF diet;D2 group,where rats were fed by purified HF diet;C group,where rats were fed on chow. After 12 weeks,diet-induced obesity rat(stop 33% based on weight)were selected for further study,and the rest rats from group D1 and D2 were excluded. The food intake and weight were weighted daily and weekly,respectively. The subcutaneous,visceral and total fat contents of rats was measured by 256-row CT scan and the Lee index was calculated accordingly. The kidney,liver,testis,spleen and heart were weighted respectively. Serum leptin and insulin levels were quantified. The pathology in liver and adipose tissues were analyzed by HE staining. Oral glucose tolerance test(OGTT)was used to compare the glucose tolerance ability. Serum total cholestero(lT-CHO),high density lipoprotein(HDL-C),low density lipoprotein(LDL-C),triglyceride(TG)and inflammatory cytokines IL-6,TNF-α were detected as well. Results: After 12 weeks,the body weight,subcutaneous fat,visceral fat,total fat mass,wet weight of liver,kidney and heart,area under blood glucose curve and the levels of serum insulin,leptin,T-CHO,LDL-C,TG,IL-6 and TNF-α in group D2 were significantly increased compared to those of group C and group D1. HDL-C of group D2 was markedly lower than that in group C(P<0. 05). The visceral fat,total fat content and HDL-C in group D1 were significantly different from those of group C(P<0. 05). Steatosis and enlarged adipocyte were found in the livers of rats in group D1 and D2,and the lesions were more significant in group D2. Conclusion: Purified HF diet was more effective in inducing metabolic abnormalities,steatosis,peripheral chronic inflammation in obese SD rat models. But lard oil HF diet was more economical when only inducing visceral steatosis was required.

Immune Responses to Trichloroethylene and Skin Gene Expression Profiles in Sprague Dawley Rats

Objective To characterize the immune reaction in SD rats exposed to trichloroethylene （TCE） and to identify the gene expression profiles involved in skin after TCE exposure. Methods Fifteen percent of TCE was injected intradermally into the rat back （100 μL/120 g） at intervals of 7 days. Whole blood was collected 24 h after the fifth or seventh intradermic administration of TCE. The percentages of CD4＋ and CD8＋ of T lymphocytes were measured by a flow cytometer. The concentrations of IFN-gamma and 1L-4 in the serum were semi-quantified by ELISA. Total RNAs of skin samples at 3 h or 24 h after the seventh dose of TCE in SD rats were extracted, and gene expression proftles of these tissues were analyszed by rat toxicology U34 array of Affymetrix. Results Obvious decline of CD4＋ in T lymphocytes was observed in the TCE-administer group. No significant concentration differences in IFN-gamma and IL-4 were found between TCE-treated and control rats. Gadd45a and Mel were significantly up regulated in skin tissue 24 h after TCE exposure. The expression regulation of immune response factors was as active as proteins associated with lipid metabolism and synthesis process in these skin samples of SD rats exposed to TCE. Conclusion T-helper type 1 cells mediate immune response can not be elicited in TCE-treated SD rats, but certain immune disorder can be induced.

Changes of Serum Trace Elements, AFP, CEA, SF, T3, T4 and IGF-Ⅱ in Different Periods of Rat Liver Cancer

Objective: Based on liver cancer model built in SD rats, the contents of trace elements (Cu, Fe, Zn, Ca and Mg), AFP, CEA, SF, TH and IGF-II in serum were measured at different stages to explore the molecular changes during the rat liver cancer development. Methods: The SD rat liver cancer model was built by using diethylnitrosamine (DENA) as the mutagen. During 16 weeks of DENA gavage, blood samples were taken in the 14th, 28th, 56th, 77th, 105th and 112th days respectively after the first day of gavage with DENA, then the contents of five trace elements (Cu, Fe, Zn, Ca and Mg), T3, T4, IGF-II, AFP, CEA and SF in serum were determined. Results: During the development of the rat liver cancer, in the test group, the Cu content significantly increased in serum, while the contents of Fe, Zn and Ca significantly decreased. The content of Mg showed no significant change. AFP and CEA of the test group showed same expression level with the control group; while the content of SF was lower than that of the control group when cancerization appeared. T3 and T4 increased at the first stage and then went down, and the content of IGF-II was always high. Conclusion: Cu, Fe, Zn, Ca, T3, T4, SF and IGF-II are closely related to the development of liver cancer. The changes of their contents in the development of cancer could enlighten the researches on cancer pathogenesis and prevention.

Effects of Terephthalic Acid on Rat Lipid Metabolism

Objective To study the effect of terephthalic acid （TPA） on lipid metabolism in Sprague-Dawley （SD） rats. Methods Five groups of SD rats that ingested 0%, 0.04%, 0.2%, 1%, and 5% TPA, respectively, were included in a 90-day subchronic feeding study. Effects of TPA on levels of serum protein, total cholesterol （TC）, triglycerides （TG）, high-density lipoprotein cholesterol （HDL）, total antioxidative capability （T-AOC）, superoxide dismutase （SOD） and malondialdehyde （MDA） were observed. Urine samples were collected and analyzed for concentration of ion. Results TPA decreased the level of serum T-AOC in a dose dependent manner. The contents of serum and bladder MDA significantly decreased in 1% and 5% TPA ingestion groups. Serum CuZn superoxide dismutase （CuZnSOD） lowered in groups of 0.2%, 1%, and 5% TPA. TPA subchronic feeding had no significant influences on serum TC, LDL or HDL, but increased serum TG, TP and ALB after administration of 0.04% and/or 0.2% TPA. Concentrations of urinary Ca^2＋, Mg^2＋, Na^＋, and K^＋ were elevated in 1% and 5% TPA groups. Conclusion Antioxidative potential decreased after TPA exposure. MDAincrease in serum and bladder tissues was one of the most important reactions in rats which could protect themselves against TPA impairment. The decrease of serum CuZnSOD was related to the excretion of Zn^2＋.

IN VIVO GROWTH OF CEREBRAL C6 GLIOMA CELLS TRANSFECTED AND TREATED WITH CX43 GENE

Objective: To study the role of connexin gene (Cx 43) on the development of glioma and the feasibility of using Cx43cDNA as a target of gene therapy of gliomas. Methods: Parental rat C6 cells and C6 cells transfected with Cx43cDNA were implanted into right caudate nucleus of SD rats as control and transfected group. Rats bearing cerebral C6 gliomas were treated with Cx43cDNA and empty vector as treated group and empty vector group. The general manifestation, survival time, MRI dynamic scanning and histopathological changes of all rats were observed. In situ hybridization and immunohisto- chemistry were used for examination of Cx43mRNA and its protein in gliomas. Average number of AgNOR staining was used for detection of cell proliferation activity, and TUNEL method for determination of cell apoptosis. Results: All rats in control and empty vector group died of cerebral gliomas within 3 weeks after implantation of C6 cells. Six out of nine rats in the transfected group and eight out of ten rats in treated group kept alive beyond 120 days with totally disappearing of the tumor foci, except one treated rat having a little residue of tumor. In gliomas of transfected and treated groups Cx43 gene expression was upregulated, proliferation activity was lowered, However, the apoptotic cells did not increase. Conclusion: The present study indicates that Cx43 gene is of crucial importance in the development of malignant glioma. It can be an effective target for gene therapy of gliomas.

Establishment and evaluation of Type 2 Diabetes Mellitus andits complications induced by low dose of multiple streptozotocin

Objective: To explore a simple, economical and feasible method for establishing type 2 diabetes mellitus and its complication model. Method: SD rats were randomly divided into two groups: normal group (15 rats) normal diet, model group (20 rats) with high glucose and high fat diet. After 2 weeks of feeding, model group was injected low dose(30mg/Kg) streptozotocin in the abdominal cavity, once a day for 6 days, normal group was injected with the same dose of citric acid buffer. Observe the changes of rat diet, body, hair, spirit, urine volume, and monitor weight, blood glucose. After 6 weeks, fast insulin, blood lipid, serum calcium, phosphorus and other biochemical indexes of rats, after HE staining observe morphologic variations changes of pancreas and kidney using microscope, and the changes of femoral bone in SD rats. Results: Compared with the normal group, the model group showed obvious symptoms, drink more, eat more, polyuria, emaciation, hyperglycemia, low calcium, low phosphorus, hyperlipidemia and other metabolic abnormalities, pancreatic atrophy, tissue fibrosis, glomerular area increased, basement membrane thickening, osteoporosis. Conclusion:High glucose and high fat diet combined with repeated intraperitoneal injecti on of low dose STZ can be successfully established the model of type 2 diabetes, and its high successful rate, low mortality rate, relatively simple, economical and feasible, has a certain significance of research on diabetes and its complications.

Expression of vasa Gene in Development Process of Germ Cells in Male Rat

In order to explore the role of vasa gene in the development of germ cells after gonad differentiation in male rats,the expression of vasa mRNA and vasa protein in 17.5-day-old fetal rats and neonatal rats was detected by real-time fluorescent quantitative PCR and immunohistochemistry method.The results showed that the expression of vasa mRNA was detected in the testis tissue of 17.5-day-old fetal rats and neonatal rats,and the expression of vasa mRNA in testis of neonatal rats was high than that in fetal rats.The expression of vasa protein was detected in neonatal rats,but it was not found in fetal rats.In conclusion,vasa gene plays an important role in the development of germ cells.However,as a marker,it can only be used to label all kinds of germ cells after formation of prespermatogonia.