Activation of de novo GSH synthesis pathway in mouse spleen after long term low-dose γ-ray irradiation

Exploring the optimal dose of low ionizing radiation to enhance immune function: a rabbit model

Primary liver cancer is one of the most common malignant tumors in China. Currently, immunotherapy for liver cancer is a research hotspot. Experimental studies and epidemiological investigations have confirmed the antineoplastic activity of low ionizing radiation. The aim of this study was to explore the optimal dose of low ionizing radiation to enhance immune function. Twenty-five New Zealand rabbits were randomly divided into five groups (n = 5 each): experimental group 1 (25 mGy), experimental group 2 (50 mGy), experimental group 3 (75 mGy), experimental group 4 (100 mGy), and the control group (0 mGy). VX-2 tumor tissue was injected into rabbits using a high-frequency B-ultrasound probe (3.5 MHz). Rabbits were irradiated, and on day 4 after irradiation, blood was collected from each rabbit. Blood chemistry, interleukin (IL)-4, interferon (IFN)-γ, immunoglobulin (Ig)G, and IgM levels were assessed. On day 15 after irradiation, macrophage phagocytic function was assessed. The rabbits were sacrificed, and the spleen was removed and weighed to calculate its spleen index. Each parameter was highest in the experimental group 3 (75 mGy). Thus, we suspect the optimal low ionizing radiation dose to improve immune function may be 75 mGy.

Ameliorative effect of fractionated low-dose gamma radiation in combination with ellagic acid on nicotine-induced hormonal changes and testicular toxicity in rats

Nicotine is an active pharmacological ingredient in cigarette smoke, which may negatively influence the male reproductive system and fertility. This study aims to investigate the effect of fractionated low-dose radiation (fractionated-LDR) and/or ellagic acid (EA) on nicotine-induced hormonal changes and testicular toxicity in rats. Nicotine was administrated orally (1 mg/kg) for 30 days, afterward, rats were treated with LDR (2 × 0.25 Gy/1-week interval), EA (10 mg/kg, 14 consecutive days p.o.), or a combination of both fractionated-LDR and EA. Rats were sacrificed 24 h after the last dose of treatment, then testes were dissected for histopathology examination, along with some biochemical parameters in serum and testicular tissue were evaluated. Nicotine-induced oxidative stress was evidenced by an increase in testicular thiobarbituric acid reactive substances (TBARS) and a decrease in reduced glutathione (GSH) content. Additionally, the activities of testicular androgenic enzymes were decreased, and the activity of serum lactate dehydrogenase (LDH) was significantly increased. The hormonal changes were verified by a noticeable reduction in follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone serum levels. Histological evaluation revealed that the testicular seminiferous tubules structure was distorted. On the contrary, fractionated-LDR plus EA attenuated the negative changes caused by nicotine observed through biochemical and histological findings. Accordingly, the exposure to fractionated-LDR combined with EA may be a promising candidate for treating hormonal changes and testicular toxicity caused by nicotine.

Organ-Specific Effects of Low Dose Radiation Exposure: A Comprehensive Review

Ionizing radiation (IR) is a high-energy radiation whose biological effects depend on the irradiation doses. Low-dose radiation (LDR) is delivered during medical diagnoses or by an exposure to radioactive elements and has been linked to the occurrence of chronic diseases, such as leukemia and cardiovascular diseases. Though epidemiological research is indispensable for predicting and dealing with LDR-induced abnormalities in individuals exposed to LDR, little is known about epidemiological markers of LDR exposure. Moreover, difference in the LDR-induced molecular events in each organ has been an obstacle to a thorough investigation of the LDR effects and a validation of the experimental results in in vivo models. In this review, we summarized the recent reports on LDR-induced risk of organ-specifically arranged the alterations for a comprehensive understanding of the biological effects of LDR. We suggested that LDR basically caused the accumulation of DNA damages, controlled systemic immune systems, induced oxidative damages on peripheral organs, and even benefited the viability in some organs. Furthermore, we concluded that understanding of organ-specific responses and the biological markers involved in the responses is needed to investigate the precise biological effects of LDR.

Ageratina adenophora causes spleen toxicity by inducing oxidative stress and pyroptosis in mice

Ageratina adenophora is an invasive weed with potent toxicological effects on livestock. Oxidative stress and pyroptosis play a pivotal role in regulating animal or human health and disease. The object of this study was to determine the mechanism underlying splenic toxicity induced by A. adenophora in a mouse model. Ageratina adenophora significantly increased the levels of reactive oxygen species and malondialdehyde, but decreased the antioxidants like catalase, superoxide dismutase, glutathione and glutathione peroxidase. In addition, the activity of the antioxidant enzymes was also decreased upon A. adenophora treatment. The induction of the pyroptosis pathway was evaluated in terms of the expression levels of Nod-like receptor protein 3, nuclear factor-κB, caspase-1, gasdermin-D and interleukin-1β, all of which were significantly elevated by A. adenophora. These findings suggest that A. adenophora impairs spleen function in mice through oxidative stress damage and pyroptosis.

Melatonin Improves Parthenogenetic Development of Vitrified⁻Warmed Mouse Oocytes Potentially by Promoting G1/S Cell Cycle Progression

This study aimed to investigate the effect of melatonin on the cell cycle of parthenogenetic embryos derived from vitrified mouse metaphase II (MII) oocytes. Fresh oocytes were randomly allocated into three groups: untreated (control), or vitrified by the open-pulled straw method without (Vitrification group) or with melatonin (MT) supplementation (Vitrification + MT group). After warming, oocytes were parthenogenetically activated and cultured in vitro, then the percentage of embryos in the G1/S phase, the levels of reactive oxygen species (ROS) and glutathione (GSH), and the mRNA expression of cell cycle-related genes (P53, P21 and E2F1) in zygotes and their subsequent developmental potential in vitro were evaluated. The results showed that the vitrification/warming procedures significantly decreased the frequency of the S phase, markedly increased ROS and GSH levels and the expression of P53 and P21 genes, and decreased E2F1 expression in zygotes at the G1 stage and their subsequent development into 2-cell and blastocyst stage embryos. However, when 10⁻⁹ mol/L MT was administered for the whole duration of the experiment, the frequency of the S phase in zygotes was significantly increased, while the other indicators were also significantly improved and almost recovered to the normal levels shown in the control. Thus, MT might promote G1-to-S progression via regulation of ROS, GSH and cell cycle-related genes, potentially increasing the parthenogenetic development ability of vitrified–warmed mouse oocytes.

Anti-apoptotic and antioxidant effects of low dose gamma irradiation against diabetes-induced brain injury in rats

The current study aimed to investigate the effect of different low doses of gamma irradiation on hyperglycemia-induced brain injury. The aim was further extended to investigate the sub-chronic effect of low dose radiation on the neuronal damage induced by diabetes. To induce diabetes, male albino rats were injected with dexamethasone (10 mg/kg/day, for 9 successive days, subcutaneously). Different diabetic groups were irradiated with 0.1, 0.25 and 0.5 Gy. The effect of low dose gamma irradiation on the hyperglycemia-induced brain damage based was analyzed at two levels: oxidative stress and apoptosis. The brain contents of glutathione, malondialdhyde and total nitrate/nitrite were measured to assess the oxidative stress. In order to evaluate the extent of the apoptotic changes in brain, tissue caspase-3 expression was detected using immunohistochemistry and the degree of DNA fragmentation was estimated. Moreover, brain tissues were examined using light microscopy to evaluate the histological changes in different groups and serum lactate dehydrogenase activity was determined as an indicator for the brain tissue damage. Results indicated that exposure to 0.5 Gy ameliorated the hyperglycemia and subsequently inhibited oxidative stress and apoptosis. Radiation exposure at this dose level also increased the survival rate of diabetic animals.

Roles of Sulfur Metabolism and Rhodanese in Detoxification and Anti-Oxidative Stress Functions in the Liver: Responses to Radiation Exposure

Organisms must confront various environmental stresses. The liver is central to protecting against such stresses in mammals, and it has many detoxification and anti-oxidative stress functions. Radiation is a source of oxidative stress and is known to affect the liver and induce anti-oxidative responses. The detoxification enzyme rhodanese, which is also called thiosulfate sulfurtransferase (TST), has been demonstrated to be induced in the liver in response to radiation. Cyanide detoxification is a function of the liver, and rhodanese is a key enzyme involved in sulfur metabolism in that detoxification. Though the anti-oxidative stress system in which sulfur molecules such as thiol compounds are involved has attracted attention as a defense against radiation, detoxification enzymes may have other roles in this defense. Understanding how these functions are affected by alterations of sulfur metabolism (including thiol compounds) after irradiation would help uncover their roles in defense against cancer and other deleterious health effects, as well as environmental stress responses. This article reviews the roles of sulfur-related metabolism in oxidative stress regulation and detoxification for recovery from liver damage after radiation exposure, with particular attention to recent findings of sulfur-related enzymes such as rhodanese, which is unique in sulfur metabolism.

Long-term dietary exposure to low concentration of dichloroacetic acid promoted longevity and attenuated cellular and functional declines in aged Drosophila melanogaster

Dichloroacetic acid (DCA), a water disinfection by-product, has attained emphasis due to its prospect for clinical use against different diseases including cancer along with negative impact on organisms. However, these reports are based on the toxicological as well clinical data using comparatively higher concentrations of DCA without much of environmental relevance. Here, we evaluate cellular as well as organismal effects of DCA at environmentally and mild clinically relevant concentrations (0.02-20.0 μg/ml) using an established model organism, Drosophila melanogaster. Flies were fed on food mixed with test concentrations of DCA for 12-48 h to examine the induction of reactive oxygen species (ROS) generation, oxidative stress (OS), heat shock genes (hsps) and cell death along with organismal responses. We also examined locomotor performance, ROS generation, glutathione (GSH) depletion, expression of GSH-synthesizing genes (gclc and gclm), and hsps at different days (0, 10, 20, 30, 40, 50) of the age in flies after prolonged DCA exposure. We observed mild OS and induction of antioxidant defense system in 20.0 μg/ml DCA-exposed organism after 24 h. After prolonged exposure to DCA, exposed organism exhibited improved survival, elevated expression of hsp27, gclc, and gclm concomitant with lower ROS generation and GSH depletion and improved locomotor performance. Conversely, hsp27 knockdown flies exhibited reversal of the above end points. The study provides evidence for the attenuation of cellular and functional decline in aged Drosophila after prolonged DCA exposure and the effect of hsp27 modulation which further incites studies towards the therapeutic application of DCA.