Melatonin prevents oxidative stress, inflammatory activity, and DNA damage in cirrhotic rats

BACKGROUND

Cirrhosis is an important health problem characterized by a significant change in liver parenchyma. In animals, this can be reproduced by an experimental model of bile duct ligation (BDL). Melatonin (MLT) is a physiological hormone synthesized from serotonin that has been studied for its beneficial properties, including its antioxidant potential.

AIM

To evaluate MLT’s effects on oxidative stress, the inflammatory process, and DNA damage in an experimental model of secondary biliary cirrhosis.

METHODS

Male Wistar rats were divided into 4 groups: Control (CO), CO + MLT, BDL, and BDL + MLT. MLT was administered (20 mg/kg) daily beginning on day 15 after biliary obstruction. On day 29 the animals were killed. Blood samples, liver tissue, and bone marrow were collected for further analysis.

RESULTS

BDL caused changes in biochemical and histological parameters and markers of inflammatory process. Thiobarbituric acid (0.46 ± 0.01) reactive substance levels, superoxide dismutase activity (2.30 ± 0.07) and nitric oxide levels (2.48 ± 0.36) were significantly lower (P < 0.001) n the groups that received MLT. DNA damage was also lower (P < 0.001) in MLT-treated groups (171.6 ± 32.9) than the BDL-only group (295.5 ± 34.8). Tissue damage and the expression of nuclear factor kappa B, interleukin-1β, Nrf2, NQO1 and Hsp70 were significantly lower in animals treated with MLT (P < 0.001).

CONCLUSION

When administered to rats with BDL-induced secondary biliary cirrhosis, MLT effectively restored the evaluated parameters.

Effect of therapeutic ultrasound on the quadriceps muscle injury in rats - evaluation of oxidative stress and inflammatory process

Muscle injuries are frequent, both in sports and work, and may be caused by stretching, distension, repetitive effort or bruising. Such lesions can lead to the generation of free radicals, triggering oxidative stress and the release of some inflammatory mediators. Therapeutic ultrasound (UST) is one of the most used electrotherapy resources in the physiotherapist's clinical practice. Our aim was to evaluate the use of therapeutic ultrasound on oxidative stress and inflammatory process in an experimental model of single quadriceps muscle injury in Wistar rats. We used a total of 28 male rats, weighing between 250-300 grams, randomly divided into four groups. In the right quadriceps, a simple impact of contusion was induced by means of a press. The animals were submitted to a daily UST treatment for a total of seven consecutive applications for three minutes each, that started 24 hours after the trauma induction. The results in the Trauma + Therapeutic ultrasound group at TBARS levels and in the enzymatic activity of SOD and GPx presented a significant difference. In the histological analysis of the Trauma + Therapeutic ultrasound group presented a reorganization of the fiber's structure and a reduction of the presence of inflammatory infiltrate. In the results of the immunohistochemistry of iNOS, TNF-α and NF-κB in muscle tissue, we observed that the group treated with ultrasound showed a reduction in the expression of the proteins. The use of UST was effective in protecting muscle tissue from oxidative stress, inflammatory process and in the rearrangement of muscle fibers.

Protective action of glutamine in rats with severe acute liver failure

BACKGROUND

Severe acute liver failure (SALF) is a rare, but high-mortality, rapidly evolving syndrome that leads to hepatocyte degeneration with impaired liver function. Thioacetamide (TAA) is a known xenobiotic, which promotes the increase of the formation of reactive oxygen species. Erythroid 2-related factor 2 (Nrf2) activates the antioxidant protection of cells. Studies have evidenced the involvement of inflammatory mediators in conditions of oxidative stress.

AIM

To evaluate the antioxidant effects of glutamine on Nrf2 activation and NFκB-mediated inflammation in rats with TAA-induced IHAG.

METHODS

Male Wistar rats (n = 28) were divided into four groups: control, control+glutamine, TAA, and TAA + glutamine. Two TAA doses (400 mg/kg) were administered intraperitoneally, 8 h apart. Glutamine (25 mg/kg) was administered at 30 min, 24 h, and 36 h. At 48 h, blood was collected for liver integrity analysis [aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP)]. The liver was harvested for histology and assessment of oxidative stress [thiobarbituric acid-reactive substances (TBARS), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione (GSH), Nrf2, Kelch-like ECH-associated protein 1 (Keap1), NADPH quinone oxidoreductase1 (NQO1), superoxide dismutase (SOD)] and inflammatory process.

RESULTS

TAA caused disruption of the hepatic parenchyma, with inflammatory infiltration, massive necrosis, and ballooning degeneration. Glutamine mitigated this tissue damage, with visible regeneration of hepatic parenchyma; decreased TBARS (P < 0.001), GSH (P < 0.01), IL-1β, IL6, and TNFα levels (P <0.01) in hepatic tissue; and decreased blood levels of AST, ALT, and ALP (P <0.05). In addition, CAT, GPx, and GST activities were restored in the glutamine group (P <0.01, P <0.01, and P <0.001, respectively vs TAA alone). Glutamine increased expression of Nrf2 (P < 0.05), NQO1, and SOD (P < 0.01), as well as levels of IL-10 (P <0.001), while decreasing expression of Keap1, TLR4, NFκB (P < 0.001), COX-2 and iNOS, (P < 0.01), and reducing NO2 and NO3 levels (P < 0.05).

CONCLUSION

In the TAA experimental model of IHAG, glutamine activated the Nrf2 pathway, thus promoting antioxidant protection, and blunted the NFκB-mediated pathway, reducing inflammation.

[Follow-up of children with moderate or severe malnutrition in the peripheral population (Brazil)]

What happens to children who develop moderate or severe malnutrition? What is done for them? Keeping in mind these questions, the present research was undertaken with the following objectives: to assess the nutritional status of children who develop moderate or severe malnutrition before the age of 5 years, after a period from 2 to 4 years after diagnosis; to assess the nutritional status of the under 5-year old siblings of these children; to study the influence of nutritional programs available in the community for the improvement of the nutritional status of the malnourished children; and to identify factors interfering with nutrition of these children during the study period. After a period of 2 to 4 years from the time of diagnosis of moderate or severe malnutrition the authors tried to locate the families of 61 malnourished children of Porto Alegre, RS (Brazil). The mothers their substitutes were interviewed and the children and siblings under 5 years of age were weighed and measured. Thirty-nine children were located. Of these, 4 (10%) died and 22 (56%) presented an increase of at least 10% in weight for age. Of the 35 children who survived, 29 (82%) still presented some degree of malnutrition (weight/age < or = 90% of the standard), 25 (71%) were stunted (height/age < or = 95%), and 5 (14%) were wasted (weight/height < or = 90%). The nutritional status of the 5-year old siblings was similar to that of the malnourished children.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk factors for early termination of breast feeding in Brazil

A prospective study was undertaken to identify possible factors related to the duration of breast feeding. Two hundred and thirty-eight mothers who had delivered normal single babies with birth weights greater than 2.5 kg and had initiated breast feeding were randomly selected at the maternity hospital, Hospital de Clinicas de Porto Alegre, Brazil, and followed by mail questionnaires until termination of breast feeding, or until the end of the first year. If no reply was received, telephone contact or home visits were made. The group of mothers who stopped breast feeding prior to the end of the third month was compared with those who extended breast feeding beyond three months with respect to socioeconomic, biological, environmental, medical and psychological factors. The variables with a significant coefficient of association with early termination of breast feeding were maternal education, past experience with breast feeding, help of a maid, help with housework provided by a relative, breast feeding orientation during prenatal care and encouragement from the husband. These factors act simultaneously, with interactions among them.