RESUMEN

Objective:To conduct a comparative analysis of the radiation damage to zebrafish embryos and the associated biological mechanism after ultra-high dose rate (FLASH) and conventional dose rate irradiation.Methods:Zebrafish embryos at 4 h post-fertilization were exposed to conventional and FLASH irradiation (9 MeV electron beam). The mortality and hatchability of zebrafish after radiation exposure were recorded. Larvae at 96 h post-irradiation underwent morphological scoring, testing of reactive oxygen species (ROS) levels, and analysis of changes in oxidative stress indicators.Results:Electron beam irradiation at doses of 2-12 Gy exerted subtle effects on the mortality and hatchability of zebrafish embryos. However, single high-dose irradiation (≥ 6 Gy) could lead to developmental malformation of larvae, with conventional irradiation showing the most significant effects ( t = 0.87-9.75, P < 0.05). In contrast, after FLASH irradiation (≥ 6 Gy), the ROS levels in zebrafish and its oxidative stress indicators including superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) were significantly reduced ( t = 0.42-15.19, P < 0.05). There was no statistically significant difference in ROS levels in incubating solutions after conventional and FLASH irradiation ( P > 0.05). Conclusions:Compared to conventional irradiation, FLASH irradiation can reduce radiation damage to zebrafish embryos, and this is in a dose-dependent manner. The two irradiation modes lead to different oxidative stress levels in zebrafish, which might be a significant factor in the reduction of radiation damage with FLASH irradiation.

RESUMEN

The thalamostriatal pathway is implicated in Parkinson's disease (PD); however, PD-related changes in the relationship between oscillatory activity in the centromedian-parafascicular complex (CM/Pf, or the Pf in rodents) and the dorsal striatum (DS) remain unclear. Therefore, we simultaneously recorded local field potentials (LFPs) in both the Pf and DS of hemiparkinsonian and control rats during epochs of rest or treadmill walking. The dopamine-lesioned rats showed increased LFP power in the beta band (12 Hz-35 Hz) in the Pf and DS during both epochs, but decreased LFP power in the delta (0.5 Hz-3 Hz) band in the Pf during rest epochs and in the DS during both epochs, compared to control rats. In addition, exaggerated low gamma (35 Hz-70 Hz) oscillations after dopamine loss were restricted to the Pf regardless of the behavioral state. Furthermore, enhanced synchronization of LFP oscillations was found between the Pf and DS after the dopamine lesion. Significant increases occurred in the mean coherence in both theta (3 Hz-7 Hz) and beta bands, and a significant increase was also noted in the phase coherence in the beta band between the Pf and DS during rest epochs. During the treadmill walking epochs, significant increases were found in both the alpha (7 Hz-12 Hz) and beta bands for two coherence measures. Collectively, dramatic changes in the relative LFP power and coherence in the thalamostriatal pathway may underlie the dysfunction of the basal ganglia-thalamocortical network circuits in PD, contributing to some of the motor and non-motor symptoms of the disease.

Asunto(s)

RESUMEN

Objective To study the effect of dopamine D1 receptor antagonist SCH23390 on the behavior of parkinsonian (PD) rats and on electrophysiological characteristics of the entopeduncular nucleus (EP).Methods Intracranial injection of 6-OHDA was conducted in 23 adult male Wistar rats to create PD animal models (experimental group) while the same amount of normal saline was injected in another 19 rats as a control group.(1) After intraperitoneal injection of SCH23390 at various concentrations of 0.010,0.015,0.020,0.025 and 0.030 mg/kg,the step frequency and the discontinuous moving frequency tests were carried out to determine the optimal concentration and time of intervention at 6 time points (10 main before,and 5～15,20～30,30～40,40～50 and 68～78 min after intervention) when all the rats were put on a treadmill at a speed of 8 r/min.(2) After recording electrodes were implanted into the EP in the rats,the signals of spikes in the EP in still and movement conditions were recorded simultaneously using the 16-Channel OmniPlex Neural Data Acquisition System.The spike signals collected were imported into Offiine Sorter to do cluster-sorting analysis and then into NeuroExplorer to analyze alterations in the firing pattern and firing rate of each type of neuron.(3) Frozen sections of the brain samples harvested by perfusion from the rats in the 2 groups were subjected to Nissl's staining and histological assay.Results (1) The behavioral tests showed that intraperitoneal injection of SCH23390 at 0.020 mg/kg at time points of 20～30 min and 30～40 min was optimal.The step frequency for the experimental group (24.47±1.35 step/min) was significantly decreased compared with that for the control group (30.77±2.06 step/min) (t=7.392,P=0.000).(2) After intervention by SCH23390,in movement and still conditions,the firing rate and variation coefficient of EP neurons were significantly higher in the experimental group than in the control group (P＜0.05).(3) The Nissl's staining showed a small number of lightly stained neurons were sparsely disposed in the injured cerebral substantia nigra and the histological assay found altogether 14 rats from which correct EP sites were collected.Conclusions This study demonstrated a negative regulating effect of dopamine D1 receptor antagonist SCH23390 on the behavior of PD rats,which may be exerted by changing the electrophysiological activity of EP.

RESUMEN

Prior to implantation, the blastocyst has to hatch out of its zona pellucida to invade the endometrium .In mammals including humans , failure of blastocyst hatching leads to infertility .Blastocyst hatching is believed to be regulated by a variety of autocrine and paracrine molecules such as proteases , cyclooxygenase-2, p38 mitogen-activated protein ki-nase, activin A and Wnt signal pathway .This article reviews the mechanisms of the key molecular regulators involved in mammalian blastocyst hatching and hatching-assisting methods , which can help clarify the mechanism of blastocyst hatching and the treatment of infertility due to failure in blastocyst hatching .

RESUMEN

Objective To investigate the protective effect and the possible mechanism of Wenshen Shengjing Decoction (WSSJD)(including Cornu Cervi Nippon Parvum , Panax ginseng, Cynomorium songaricum, Cistanche deserticola,Radix Astragali, Epimedium brevicornum, Angelica sinensis.) on cyclophosphamide induced testicular oxidative damage in mice . Methods Eight-week-old male Kunming mice were assigned .Mice in normal control group received intraperitoneally nor-mal saline, and mice in Western medicine group ,WSSJD group and model group were injected intraperitoneally with cyclo-phosphamide [80 mg/(kg? d) ]for five days.Then mice in Western medicine group and WSSJD group were gavaged with clomifene citrate or WSSJD for 30 days consecutively .The epididymal sperm count and sperm viability were recorded , and the structure of seminiferous epithelium was observed .The content of malondialdehyde (MDA) and glutathione (GSH), and activities of glutathione peroxidase ( GSH-Px) and catalase ( CAT) in testicular tissue were detected .Immunohisto-chemical technique was used to detect the expression of survivin in spermatogenic cells .The apoptosis of spermatogenic cells in the testes was detected by TUNEL assay .Results Compared with model and Western medicine groups ,the epidid-ymal sperm count and sperm viability rate , the development of seminiferous epithelium , and the activities of GSH-Px and CAT significantly increased , while the MDA content significantly decreased in WSSJD group .The expression of survivin in spermatogenic cells was significantly improved .The apoptotic indexes of seminiferous tubules and spermatogenic cells significantly decreased in WSSJD group .Conclusion These results suggest that WSSJD can significantly improve the impaired reproductive function induced by cyclophospamide in mice by enhancing the antioxidative capability in testes and reducing the apoptosis of spermatogenic cells .