Acutely applied melatonin prevents CCl4-induced testicular lesions in rats: the involvement of the oxidative capacity and arginine metabolism

Abstract Carbon tetrachloride (CCl4) represents an organic chemical that causes reactive oxygen species derived organ disturbances including male infertility. Melatonin (MLT) is a neurohormone with strong antioxidant capacity, involved in numerous physiological processes. In this study we evaluated the capability of MLT, administered in a single dose of 50 mg/kg, to preserve the testicular tissue function after an acute administration of CCl4 to rats. The disturbance in testicular tissue and the effects of MLT after CCl4 exposure were estimated using biochemical parameters that enabled us to determine the tissue (anti)oxidant status and the intensity of arginine/nitric oxide metabolism. Also, the serum levels of testosterone and the histopathological analysis of tissue gave us a better insight into the occurring changes. A significant diminution in tissue antioxidant defences, arginase activity and serum testosterone levels, followed by the increased production of nitric oxide and extensive lipid and protein oxidative damage, was observed in the CCl4-treated group. The application of MLT after the CCl4 caused changes, clearly visible at both biochemical and histological level, which could be interpreted mainly as a consequence of general antioxidant system stimulation and a radical scavenger. On the other hand, the application of MLT exerted a limited action on the nitric oxide signalling pathway.

Effects of silica-rich water on systemic and peritoneal inflammation in rats exposed to chronic low-level (900-MHz) microwave radiation.

Immunomodulating effect of silica-rich water represents a novel field for research, especially regarding its features toward environmental pollutants. The aim of our study was to evaluate the effects of silica-rich water intake on systemic and peritoneal inflammation in rats that were chronically exposed to the low-level microwave (MW) radiation from mobile phones. Wistar Albino rats were exposed to 900 MHz MW radiation for 3 months. The four-treatment model involved rats with standard water (SW) or experimental silica-rich water intake (EW). Peritoneal macrophages (PMs) were harvested using peritoneal lavage and divided into non-stimulated and lipopolysaccharide (LPS) stimulated subgroups. The MW-exposed rats with silica-rich water (MW+EW) had lower serum tumor necrosis factor α (TNF-α) and interleukin 2 (IL-2) levels, but higher IL-10 levels, than MW+SW rats (p < 0.05). The higher TNF-α production by non-stimulated MW exposed PMs was ameliorated by the silica-rich water (p < 0.01). The MW exposition suppressed LPS potential for TNF-α synthesis in both water type groups, with greater suppression in animals that took standard water. Our results show the modulating effect of silica-rich water toward MW-induced systemic and peritoneal inflammation, which reflects the water ability to shape monocyte plasticity, thereby altering the balance between their proinflammatory and anti-inflammatory properties.

Effect of silicon-rich water intake on the systemic and peritoneal inflammation of rats with chronic low levels of aluminum ingestion.

BACKGROUND AND OBJECTIVES: Study evaluated effect of silicon-rich water intake on systemic inflammation and functional characteristics of peritoneal macrophages (PMs) of rats that were chronically exposed to dietary aluminum. METHODS: One month-old female Wistar Albino rats were administered aluminum chloride dissolved in distilled water (1.6mg/kg body weight in 0.5mL) by gavage for 90days. The rats were then given standard (6mg/L) or silicon-rich water (19mg/L silicon) (n=7/group). Control rats underwent sham gavage and received standard or silicon-rich water (n=7/group). Blood was assessed for cytokine levels. Unstimulated and lipopolysaccharide (LPS)-stimulated PMs were assessed in terms of phagocytic activity and cytokine secretion in vitro. RESULTS: Chronic exposition to dietary aluminum and silicon-rich drinking water did not change serum TNF-α levels. Aluminum increased serum IL-2 and this was reversed by silicon-rich water. The aluminum-exposed rats had higher serum sICAM-1 than sham-gavaged, unrelated to type of water. LPS-stimulated PMs from aluminum-intoxicated animals exhibited low phagocytic activity and release of TNF-α, this was significantly improved by silicon-rich water intake. In the presence of silicon-rich water, LPS-stimulated and unstimulated PMs from aluminum-exposed rats produced significantly more IL-10. CONCLUSIONS: Chronic ingestion of aluminum, increases systemic and peritoneal inflammation and PM dysfunction. The presence of high levels of the natural aluminum antagonist silicon in the drinking water restored IL-10 and TNF-α PM secretion, preventing prolonged inflammation. Thus, silicon intake can decrease the immunotoxicity of aluminum.

Integrative approach to diagnosis of genital human papillomaviruses (HPV) infection of female.

Human papillomavirus (HPV) is a virus from the papillomavirus family that is capable of infecting humans. Some types of HPVs cause warts, while others can lead to cancers of the cervix, vulva, vagina, penis, oropharynx and anus. High-risk human papillomavirus (hr HPV) has been detected in almost all cervical squamous cell carcinomas and adenocarcinomas. All patients examined by colposcopy. Cervical swab is routinely done and patients are screened with both HPV DNA by Real Time Polimerase Chain Reaction (RT PCR) testing and Pap testing. Pictures obtained by colposcopy were examined by indirect Bi-Digital O-Ring Test (BDORT) by using reference control substance (RCS): HPV 16, HPV 18, and Integrin α5 ß1. BDORT was developed by Prof. Omura Y. of New York and received U.S. patent in 1993. For detection of HPV DNA we used RT PCR and standard Qiagen method which detect 18 types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 6, 11, 42, 43, 44) of HPV from smear. From 63 patients where is BDORT indicated presence of HPV, in 49 patients (77.8%) RT PCR confirmed presence of HPV. From 63 patients in 54 patients (85.7%), we detected, by colposcopic exam, some kind of lesions associated with HPV infection. Results obtained by RT PCR: one type (1/18) of DNA HPV in 25 patients (51.02%), 2 types (2/18) in 15 patients (30.61%) and 3 types (3/18) in 9 patients (18.37%). Although BDORT results usually have higher sensitivity and detection rate is much higher, it can be used together with RT PCR in detection of HPV and cervical lesions associated with HPV infection.

Predicting the biological effects of mobile phone radiation absorbed energy linked to the MRI-obtained structure.

The nature of an electromagnetic field is not the same outside and inside a biological subject. Numerical bioelectromagnetic simulation methods for penetrating electromagnetic fields facilitate the calculation of field components in biological entities. Calculating energy absorbed from known sources, such as mobile phones when placed near the head, is a prerequisite for studying the biological influence of an electromagnetic field. Such research requires approximate anatomical models which are used to calculate the field components and absorbed energy. In order to explore the biological effects in organs and tissues, it is necessary to establish a relationship between an analogous anatomical model and the real structure. We propose a new approach in exploring biological effects through combining two different techniques: 1) numerical electromagnetic simulation, which is used to calculate the field components in a similar anatomical model and 2) Magnetic Resonance Imaging (MRI), which is used to accurately locate sites with increased absorption. By overlapping images obtained by both methods, we can precisely locate the spots with maximum absorption effects. This way, we can detect the site where the most pronounced biological effects are to be expected. This novel approach successfully overcomes the standard limitations of working with analogous anatomical models.

Melatonin protects rat thymus against oxidative stress caused by exposure to microwaves and modulates proliferation/apoptosis of thymocytes.

The aim of the study was to evaluate the effect of melatonin on oxidative stress, DNA fragmentation, apoptsis and proliferation in thymus tissue of rats exposed to microwaves. Wistar rats were divided in four groups: I - treated with saline; II - treated with melatonin; III - microwaves exposed; IV - microwaves exposed and melatonin treated. Melatonin (2 mg/kg i.p.) was administered daily. Animals were sacrificed after 20, 40 and 60 days. A significant increase in malondialdehyde and carbonyl group content, as well as decrease in catalase and increase in xanthine oxidase activity were registered under microwave exposure. Melatonin prevented the increase in malondialdehyde and carbonyl group content, and reversed the effect on catalase and xanthine oxidase activity. Both, alkaline and acid DNase activity were increased due to microwave exposure. Furthermore, microwaves caused increase in apoptosis rate (detected using Annexin V-FITC/PI kit) and reduced proliferative capacity of thymocytes (induced by ConA). However, melatonin caused decrease in alkaline and acid DNase activity, decrease in apoptotic rate and increase in proliferation rate of thymocytes. Melatonin exerts protective effects on rat thymocytes by modulating processes of apoptosis and proliferation, and causes decrease in DNA fragmentation and oxidative stress intensity under exposure to microwaves.

Melatonin reduces oxidative stress induced by chronic exposure of microwave radiation from mobile phones in rat brain.

PURPOSE: The aim of the study was to evaluate the intensity of oxidative stress in the brain of animals chronically exposed to mobile phones and potential protective effects of melatonin in reducing oxidative stress and brain injury. MATERIALS AND METHODS: Experiments were performed on Wistar rats exposed to microwave radiation during 20, 40 and 60 days. Four groups were formed: I group (control)- animals treated by saline, intraperitoneally (i.p.) applied daily during follow up, II group (Mel)- rats treated daily with melatonin (2 mg kg(-1) body weight i.p.), III group (MWs)- microwave exposed rats, IV group (MWs + Mel)- MWs exposed rats treated with melatonin (2 mg kg(-1) body weight i.p.). The microwave radiation was produced by a mobile test phone (SAR = 0.043-0.135 W/kg). RESULTS: A significant increase in the brain tissue malondialdehyde (MDA) and carbonyl group concentration was registered during exposure. Decreased activity of catalase (CAT) and increased activity of xanthine oxidase (XO) remained after 40 and 60 days of exposure to mobile phones. Melatonin treatment significantly prevented the increase in the MDA content and XO activity in the brain tissue after 40 days of exposure while it was unable to prevent the decrease of CAT activity and increase of carbonyl group contents. CONCLUSION: We demonstrated two important findings; that mobile phones caused oxidative damage biochemically by increasing the levels of MDA, carbonyl groups, XO activity and decreasing CAT activity; and that treatment with the melatonin significantly prevented oxidative damage in the brain.