ABSTRACT
Objective To explore the effect of neonatal exposure to different doses of Bisphenol A (BPA)on the hypothalamic -pituitary -testis axis in toddler and adolescent male rats.Methods Neonatal male Sprague -Daw-ley rats were randomly divided into 5 groups through random digital table method:control group,vehicle group,low -dose BPA [25 μg/(kg · d)]group,medium -dose BPA [50 μg/(kg · d)]group and high -dose BPA [250μg/(kg·d)]group.The rats were subcutaneously injected with respective agents on postnatal days 1 -7 (PND 1 -7).Pups were sacrificed on PND 22 and PND 50.The hypothalamus and testis were taken and weighed.The hypotha-lamic Kiss -1 mRNA and the testis androgen receptor (AR)mRNA were tested by using real -time fluorescence quan-titative and the levels of serum luteinizing hormone (LH),follicle stimulating hormone (FSH),testosterone (T)were tested by using radio immunity method,and inhibin B was measured by using enzyme linked immunosorbent assay. Results Compared with the controls,the level of serum FSH [(1 .610 0 ±0.693 2)IU /L,(1 .574 3 ±0.675 0)IU /L vs (2.362 9 ±0.580 3)IU /L](F =3.314,P =0.026),LH [(3.876 3 ±0.908 0)IU /L,(3.603 8 ±1 .350 2)IU /L vs (5.302 5 ±0.768 4)IU /L](F =3.1 39,P =0.027)and T [(0.383 8 ±0.1 77 8)μg/L,(0.442 5 ±0.21 4 1 )μg/L vs (0.782 5 ±0.282 1 )μg/L](F =5.1 06,P <0.01 )of medium and high -dose BPA groups,were decreased in PND 22,and the organ coefficient of testis [(0.952 90 ±0.049 1 5)%,(0.969 20 ±0.045 82)% vs (1 .022 80 ± 0.01 1 08)%](F =1 0.326,P <0.01 )and serum T [(1 .758 6 ±0.369 6)μg/L,(1 .71 8 8 ±0.395 7)μg/L vs (3.357 5 ±0.749 8)μg/L](F =1 3.799,P =0.01 2)were significantly decreased in PND 50.In high -dose BPA group of PND 22,the expression of hypothalamic Kiss -1 mRNA (0.068 80 ±0.01 1 79)was increased compared with the other groups (F =272.1 25,P <0.01 ),while in PND 50,compared with control group,the Kiss -1 mRNA (0.002 00 ±0.000 25,0.001 90 ±0.000 48 vs 0.001 40 ±0.000 1 7)of medium -and high -dose BPA groups was decreased(F =1 91 .826,P <0.01 ).Conclusions Neonatal exposure to the medium and high -dose BPA may impair the function of testis in toddler and adolescent male rats,and affect the hypothalamus -pituitary -testis axis.Neonatal exposure to the low -dose BPA does not have a significant influence on the hypothalamus -pituitary -testis axis.
ABSTRACT
@#Objective To identify the effects of parenteral nutrition (PN) on the gene expressions of rat intestinal inflammatory cytokincs and receptors and to explore the role of these changes in PN-related intestinal impairment. Methods Totally 12 male Sprague-Dawley rats were equally divided into the control group and the PN group. A silastic catheter was inserted into the right jugular vein of each rat. No food or water was administered to the PN group except for a continuous 24-hour PN infusion through the silastic catheter in the jugular vein. The control group, while being regularly fed, was administered with an infusion of normal saline through the silastic catheter in thc jugular vein. After 7 days, intestinal tissues were taken for electron microscopy and real-time PCR array to analyze thc microstructure change in rat intestine and thc gene expressions of inflammatory cytokines and their receptors. Results Electron microscopy revealed atrophy of microvillus, engorgement of mitochondria, cell-cell junction breakage, and several apoptotic bodies in the PN group and normal intestinal microstructure in the control group. Compared with the control group, the PN group showed an up-regulation in the gene expressions of interferon γ, interleukin-1 receptor type I , interlcukin-8 receptor type b and a down-regulation in the gene expressions of CC chemokine ligand 17 (CCL17) , CCL19, CCL21, CCL22, CCL9, CXC chemokine receptor 3, CC chemokine receptor 3 ( CCP3 ), CCR7, CCR5, C-reactive protein, and interleukin-10. Conclusions PN influences the gene expressions of rat intestinal inflammatory cytokincs and receptors. The expression of cytokine interferon γ increases and that of interleukin-10 declines, and the expressions of CCL19, CCL21, CXC chemokine receptor 3, CCR3,CCR7, and CCR5 decline. The alterations of these genes may be associated with the impairment of intestinal immune and mechanical functions.
ABSTRACT
Objective To explore the effects of physical exercises on recurrent seizures-induced long-term learning and memory deficits and on the expression of zinc transporter-3(ZnT-3)in hippocampuses of developmental period rats.Methods Sprague-Dawley rats aged 21 d were randomly divided into blank control group,exercises control group,seizure group and seizure plus exercises group.Abdominal cavity injections of penicillin or saline were used to induce recurrent seizure or as a control in the corresponding groups.During the postnatal(P)39-44 d and P61-65 d periods,Morris water-maze tests were administered to evaluate spatial learning and memory capacity.During the P48-53 d period,the rats in exercises control and seizure plus exercises groups were subjected to a 30-min daily aerobic exercises program for 6 d.The real-time reverse transcription-polymerase chain reaction(RT-PCR)method was used to detect the expression of ZuT-3 mRNA in hippocampuses of all rats at P66 d. Results Searching strategy:There was a decreasing incidence of marginal strategy and an increasing trend in the use of taxis and straight line strategy in all four groups.The scores on d 1 and 4 were significantly higher in two control groups than in two seizure groups in water-maze test(all P＜0.05).By d 2 the exercises control and seizure plus exercises groups were scoring significantly higher than the bland control and seizure groups(P＜0.05).Memory test:The frequency of passing through the platform quadrant decreased significantly in the two seizure groups compared to the two control groups in both probe tests(all P＜0.05).RT-PCR test:ZnT-3 mRNA expressions in hippocampuses were significantly higher in seizure plus exercises group than in any other groups. Conclusions Penicillin-induced recurrent seizures can induce long-term damage on learning and memory capacity in developmerital period rats.Physical exercises can improve learning capacity.It's mechanism may be related to the up-regulation of ZnT-3 expression in hippocampus of rats.