Ultrastructural evaluation of the radioprotective effect of sodium selenite on submandibular glands in rats

In-vivo and in vitro assessments of the radioprotective potential natural and chemical compounds: a review

PURPOSE

The study of the radioactive role of natural and chemical substances on human and animal studies has been the subject of research by some researchers. Therefore, the review of some of the past and current studies conducted in this field, can provide helpful information to elucidate of the importance of radioprotective components in reducing radiation exposure side effects.

METHODS

The authors search for keywords including In vitro, In vivo, Radioprotective, Ionizing radiation, and Vitamin in ScienceDirect, Scopus, Pubmed, and Google Scholar databases to access previously published articles and search for more reference articles on the role of radioprotective materials from natural and chemical compounds.

RESULTS

Radiation exposure can produce reactive oxygen species (ROS) in the body, however most of which are eliminated by the body's natural mechanisms, but when the body's antioxidant systems do not have enough ability to neutralize free radicals, oxidative stress occurs, which causes damage to DNA and body tissues. Therefore, it is necessary use of alternative substances that reduce and inhibit free radicals.

CONCLUSION

In general, recommended that antioxidant component(s) can be protect tissue damages in humans or animals, due to the their ability to scavenge free radicals generated by ionizing radiation.

The Potential Protective Effect of Orange Peel and Selenium against 17β-Estradiol- Induced Chronic Non-Bacterial Prostatitis in Rats

BACKGROUND

Prostate Cancer (PCa) is defined as a major health problem faced by the male population.

AIM

We aimed to investigate the protective effects of Orange Peel Extract (OPE) and/or Selenium (Se) on chronic non-bacterial prostatitis in a rat model.

METHODS

Fifty-six adult male Wistar albino rats were castrated; after 5 days, they were divided randomly into eight groups (n= 7). The control group received saline treatment; while 17β-estradiol (E2) (0.25mg/kg) was injected subcutaneously in rats from Groups V, VI, VII, and VIII to induce chronic non-bacterial prostatitis. They were then treated with OPE (400mg/kg body weight; Groups II, IV, VI, and VIII) and/or sodium selenite (0.5mg/kg body weight; Groups III, IV, VII, and VIII) for 30 days. Interleukin-2 (IL2) and Prostate Cancer Antigen 3 (PCA3) mRNA expressions were determined using qPCR; Prostate-Specific Antigen (PSA) protein expression was determined immunohistochemically. Prostate tissue histology was examined by hematoxylin and eosin staining, and the levels of oxidative stress markers and antioxidant enzymes were measured.

RESULTS

E2 administration significantly increased IL2 and PCA3 mRNA expressions, and PSA protein expression. It also increased the prostate wet weight and body weight, and lipid peroxidation, nitric oxide, TNF-α, and IL-1β levels, decreased the glutathione and antioxidant enzyme levels and caused distinct histological alterations in the prostate gland. OPE and/or Se markedly improved all the studied parameters due to their antioxidant properties and anti-inflammatory effects.

CONCLUSION

OPE and Se showed protective effects against 17β-estradiol-induced chronic non-bacterial prostatitis. These results suggest that protection of chronic non-bacterial prostatitis by OPE+Se combination involves anti-oxidation and anti-inflammation. Moreover, their synergistic mechanism was mostly achieved via the regulation of oxidative stress and inflammation processes.

Selenium as an adjuvant for modification of radiation response

Ionizing radiation plays a central role in several medical and industrial purposes. In spite of the beneficial effects of ionizing radiation, there are some concerns related to accidental exposure that could pose a threat to the lives of exposed people. This issue is also very critical for triage of injured people in a possible terror event or nuclear disaster. The most common side effects of ionizing radiation are experienced in cancer patients who had undergone radiotherapy. For complete eradication of tumors, there is a need for high doses of ionizing radiation. However, these high doses lead to severe toxicities in adjacent organs. Management of normal tissue toxicity may be achieved via modulation of radiation responses in both normal and malignant cells. It has been suggested that treatment of patients with some adjuvant agents may be useful for amelioration of radiation toxicity or sensitization of tumor cells. However, there are always some concerns for possible severe toxicities and protection of tumor cells, which in turn affect radiotherapy outcomes. Selenium is a trace element in the body that has shown potent antioxidant and radioprotective effects for many years. Selenium can potently stimulate antioxidant defense of cells, especially via upregulation of glutathione (GSH) level and glutathione peroxidase activity. Some studies in recent years have shown that selenium is able to mitigate radiation toxicity when administered after exposure. These studies suggest that selenium may be a useful radiomitigator for an accidental radiation event. Molecular and cellular studies have revealed that selenium protects different normal cells against radiation, while it may sensitize tumor cells. These differential effects of selenium have also been revealed in some clinical studies. In the present study, we aimed to review the radiomitigative and radioprotective effects of selenium on normal cells/tissues, as well as its radiosensitive effect on cancer cells.

Radioprotective effects of pyrroloquinoline quinone on parotid glands in C57BL/6J mice

The aim of the present study was to investigate whether pyrroloquinoline quinine (PQQ) serve a radioprotective role in parotid gland damage induced by total body irradiation (TBI) in C57BL/6J mice. A total of 15 female 8-week-old C57BL/6J mice were randomly assigned into three treatment groups: i) Untreated control (no irradiation); ii) 4 gray (Gy) X-ray irradiation; iii) 4 Gy X-ray irradiation with additional dietary PQQ (4 mg PQQ/kg in normal diet). Each group included five mice. After 4 weeks, all animals were collected for evaluating the phenotype, body weight, pathological and biochemical parameters. The results indicated that PQQ had biological effects on total body phenotype. PQQ could partially rescue TBI-induced damage to parotid glands. In addition, PQQ served radioprotective effects on parotid glands via multiple mechanisms, such as promoting proliferation, inhibiting apoptosis and senescence, upregulating antioxidant ability, scavenging reactive oxygen species and reducing DNA damage. The results of the present study demonstrate that PQQ serves a radioprotective role in parotid gland damage induced by TBI, possibly via inhibiting oxidative stress and participating in DNA damage repair. The study provides experimental and theoretical knowledge for the development of radioprotective clinical drugs.

Radioprotective effect of sodium selenite on developing teeth

Radioprotective agents like selenium are used to reduce the damage caused by radiation in healthy tissues. The aim of this study was to evaluate the effect of sodium selenite on the development of the molars of offspring of rats irradiated during odontogenesis. Twenty pregnant rats were randomly divided into 4 groups: control, irradiated, selenium and selenium/irradiated. The selenium and selenium/irradiated groups received 0.3 mg/kg of sodium selenite at 18 days of pregnancy. The rats of the irradiated and selenium/irradiated groups received a single dose of 4 Gy of X rays on the abdominal region at the 19th day of pregnancy. The offspring was sacrificed at 3 and 4 days after birth for evaluation of the birefringence of the enamel organic matrix, and at 30 days for evaluation of the intercuspal dimensions of the molars. The selenium/irradiated group was similar to the irradiated group with respect to the thickness and irregularity of the enamel organic matrix region in the evaluated birefringence, as the intercuspal dimensions of the molars. In conclusion, sodium selenite had no radioprotective action on the development of the molars of offspring of rats irradiated during odontogenesis and had a toxic effect in the initial time.

TIGAR overexpression diminishes radiosensitivity of parotid gland fibroblast cells and inhibits IR-induced cell autophagy

Our previous study proved that TP53-induced glycolysis and apoptosis regulator (TIGAR) abrogation is able to radiosensitize glioma cells. Whether TIGAR over-expression has radio-protective effect in human parotid gland cells is still unknown. In this study human parotid gland fibroblast Hs 917.T cells were transfected with pcDNA3.1-TIGAR, and clonogenic assay was performed to investigate the radiosensitivity of Hs 917.T cells over-expressing pcDNA3.1 or pcDNA3.1-TIGAR. Western blot was carried out to demonstrate the autophagy activity of cells being irradiated, and immunofluorescence assay was used to evaluate the DNA damage repair process of irradiated Hs 917.T cells. It was revealed that TIGAR over-expression could diminish the radiosensitivity of Hs 917.T cells, and the autophagy level induced by ionizing radiation (IR) was also decreased by TIGAR transfection. The mechanism might rely on TIGAR over-expression induced ROS scavenging and NADPH increasing. Using autophagy inhibitor, it was also elaborated that IR-induced autophagy in Hs 917.T cells was protective autophagy but not traumatic autophagy.

Sodium selenite treatment restores long-lasting ovarian damage induced by irradiation in rats: impact on oxidative stress and apoptosis

The deleterious damage of reproductive function following radiotherapy is of increasing importance. In the present study, we investigated the impact of long-term sodium selenite (SS) treatment on radiotherapy-induced ovarian injury in a rat model. Two-week after radiation exposure vaginal cyclicity was arrested, and serum FSH level was elevated in irradiated female rats. SS significantly ameliorated ovarian and uterine oxidative stress induced by irradiation through decreasing the lipid peroxide level and increasing the glutathione level, and glutathione peroxidase activity. In the presence of SS, ovarian cytochrome c and caspase 3 expressions triggered by radiotherapy were decreased. SS significantly counteracted radiation-induced a widespread loss of ovarian follicles and caused further stimulation of follicular proliferation through enhancing PCNA expression. Despite such alteration in ovarian function, serum estradiol level did not change after irradiation, whereas SS significantly increased it. In conclusion, long-term SS treatment improved reproductive development, which was impaired by radiotherapy.

Sodium selenite improves folliculogenesis in radiation-induced ovarian failure: a mechanistic approach

Radiotherapy is a major factor contributing to female infertility by inducing premature ovarian failure (POF). Therefore, the need for an effective radioprotective agent is evident. The present study investigated the mechanism of potential radioprotective effect of sodium selenite on radiation-induced ovarian failure and whether sodium selenite can stimulate in-vivo follicular development in experimental rats. Immature female Sprague-Dawely rats were either exposed to gamma-radiation (3.2 Gy, LD₂₀), once and/or treated with sodium selenite (0.5 mg/kg), once daily for one week before irradiation. Follicular and oocyte development, apoptotic markers, proliferation marker as well as oxidative stress markers were assessed 24-h after irradiation. In addition, fertility assessment was performed after female rats became completely mature at two months of age. Sodium selenite significantly enhanced follicular development as compared to the irradiated group. Sodium selenite significantly reversed the oxidative stress effects of radiation that was evidenced by increasing in lipid peroxide level and decreasing in glutathione level, and glutathione peroxidase (GPx) activity. Assessment of apoptosis and cell proliferation markers revealed that caspase 3 and cytochrome c expressions markedly-increased, whereas, PCNA expression markedly-decreased in the irradiated group; in contrast, sodium selenite treatment prevented these alterations. Histopathological examination further confirmed the radioprotective efficacy of sodium selenite and its in-vivo effect on ovarian follicles’ maturation. In conclusion, sodium selenite showed a radioprotective effect and improved folliculogenesis through increasing ovarian granulosa cells proliferation, estradiol and FSH secretion, and GPx activity, whilst decreasing lipid peroxidation and oxidative stress, leading to inhibition of the apoptosis pathway through decreasing the expressions of caspase 3 and cytochrome c.

Radiation protection following nuclear power accidents: a survey of putative mechanisms involved in the radioprotective actions of taurine during and after radiation exposure

There are several animal experiments showing that high doses of ionizing radiation lead to strongly enhanced leakage of taurine from damaged cells into the extracellular fluid, followed by enhanced urinary excretion. This radiation-induced taurine depletion can itself have various harmful effects (as will also be the case when taurine depletion is due to other causes, such as alcohol abuse or cancer therapy with cytotoxic drugs), but taurine supplementation has been shown to have radioprotective effects apparently going beyond what might be expected just as a consequence of correcting the harmful consequences of taurine deficiency per se. The mechanisms accounting for the radioprotective effects of taurine are, however, very incompletely understood. In this article an attempt is made to survey various mechanisms that potentially might be involved as parts of the explanation for the overall beneficial effect of high levels of taurine that has been found in experiments with animals or isolated cells exposed to high doses of ionizing radiation. It is proposed that taurine may have radioprotective effects by a combination of several mechanisms: (1) during the exposure to ionizing radiation by functioning as an antioxidant, but perhaps more because it counteracts the prooxidant catalytic effect of iron rather than functioning as an important scavenger of harmful molecules itself, (2) after the ionizing radiation exposure by helping to reduce the intensity of the post-traumatic inflammatory response, and thus reducing the extent of tissue damage that develops because of severe inflammation rather than as a direct effect of the ionizing radiation per se, (3) by functioning as a growth factor helping to enhance the growth rate of leukocytes and leukocyte progenitor cells and perhaps also of other rapidly proliferating cell types, such as enterocyte progenitor cells, which may be important for immunological recovery and perhaps also for rapid repair of various damaged tissues, especially in the intestines, and (4) by functioning as an antifibrogenic agent. A detailed discussion is given of possible mechanisms involved both in the antioxidant effects of taurine, in its anti-inflammatory effects and in its role as a growth factor for leukocytes and nerve cells, which might be closely related to its role as an osmolyte important for cellular volume regulation because of the close connection between cell volume regulation and the regulation of protein synthesis as well as cellular protein degradation. While taurine supplementation alone would be expected to exert a therapeutic effect far better than negligible in patients that have been exposed to high doses of ionizing radiation, it may on theoretical grounds be expected that much better results may be obtained by using taurine as part of a multifactorial treatment strategy, where it may interact synergistically with several other nutrients, hormones or other drugs for optimizing antioxidant protection and minimizing harmful posttraumatic inflammatory reactions, while using other nutrients to optimize DNA and tissue repair processes, and using a combination of good diet, immunostimulatory hormones and perhaps other nontoxic immunostimulants (such as beta-glucans) for optimizing the recovery of antiviral and antibacterial immune functions. Similar multifactorial treatment strategies may presumably be helpful in several other disease situations (including severe infectious diseases and severe asthma) as well as for treatment of acute intoxications or acute injuries (both mechanical ones and severe burns) where severely enhanced oxidative and/or nitrative stress and/or too much secretion of vasodilatory neuropeptides from C-fibres are important parts of the pathogenetic mechanisms that may lead to the death of the patient. Some case histories (with discussion of some of those mechanisms that may have been responsible for the observed therapeutic outcome) are given for illustration of the likely validity of these concepts and their relevance both for treatment of severe infections and non-infectious inflammatory diseases such as asthma and rheumatoid arthritis.

Radioprotection of sensitive rat tissues by oligoelements Se, Zn, Mn plus Lachesis muta venom

In this study we first evaluated the general radioprotective efficacy of Se, Zn and Mn (4 µg/ml each) plus Lachesis muta venom (4 ng/ml) combination (O-LM) by determining survival on rats irradiated with lethal doses of gamma-rays. The aim of the second part of the study was to investigate the O-LM ability to prevent ionizing radiation-induced damage on small intestine, bone marrow and submandibular glands. Hence, histological characteristics and functional studies, together with proliferation and apoptotic marker levels on whole body irradiated rats with a 5 Gy dose were evaluated. Results show that all animals of the untreated group died after whole body irradiation with 8 and 10 Gy while 60 day-survival was more than 80% and 40% in O-LM-treated animals, respectively. Histopathological examinations revealed a high degree of small intestine and submandibular gland radioprotection 3 days post-irradiation. O-LM inhibited histological damage on small intestine, restoring the radiation-induced reduction in villous height and crypt number. O-LM prevented radiation-induced loss of salivary gland function and morphological alterations. These effects were associated to a complete inhibition of radiation-induced apoptosis. Furthermore, studies performed 30 days post-irradiation revealed that O-LM significantly improved bone marrow repopulation, increasing all medullar progenies to the extent of the non-irradiated animals, and completely prevented permanent submandibular gland alterations. Based on the present results and taking into account that O-LM is being safely administered in phase I clinical trial as an immunomodulator, we conclude that O-LM is a non-toxic promising approach to achieve radioprotection for patients undergoing radiotherapy.