Efeitos do óleo de copaíba (Copaifera reticulata) sobre a inflamação, metabolismo e estado oxidativo de ratos com artrite por adjuvante

• Autor(a) principal: Ghizoni, Cristiane Vizioli de Castro
• Data de Publicação: 2017
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/1869
• topic: Bioquímica; Óleo de copaíba; Artrite induzida por aduvante; Metabolismo hepático; Morfologia hepática; Estado oxidativo; Brasil.; Ciências Biológicas; Bioquímica

Rheumatoid arthritis is an autoimmune disease characterized by chronic and systemic inflammation that affects the synovial membranes, articular cartilages and bones. The articular cartilage becomes hyperplasic with participation of proinflammatory cells and cytokines, reactive oxygen species (ROS) and inflammatory mediators, which cause tissue injury. Rheumatoid arthritis is a systemic disease and in addition to the joints other organs are affected, such as brain and heart. Adjuvantinduced arthritis is an experimental immunopathology in rats that shares many features with rheumatoid arthritis in humans. These animals present systemic inflammation and additionally to articular sites other organs are affected, as the liver, which presents morphological and metabolic alterations associated to a pronounced oxidative stress. Copaiba oil is an oleoresin extracted from trees of the genus Copaifera, abundant in the Brazilian Amazon and worldly commercialized for several therapeutic purposes, specially anti-inflammatory. No study has until now evaluated if the copaiba oil is able to improve the chronic and systemic inflammation, such as that occurs in rheumatoid arthritis. The present study therefore was planned to investigate the action of copaiba oil (C. reticulata Ducke), containing 37.6% of β-caryophyllene, orally administrated on the systemic inflammation, oxidative status and liver histology and metabolism of rats with adjuvant-induced polyarthritis. Previous studies also indicate that the treatment of rats with copaiba oil seems to be harmful to the liver. Thus, plasma parameters were additionally accessed to evaluate potential toxicity of the oil on the liver, the first organ that receives the oil when ingested orally. Copaiba oil was provided by EMBRAPA/PA and its antioxidant activity in vitro was measured by DPPH and ABTS assays. Induction of polyarthritis was performed in Holtzman rats (180-200 g) with Freund's adjuvant. The rats were distributed into six groups: controls; controls treated with copaiba oil at a dose of 0.58 and 1.15 g·Kg-1, arthritis, and arthritis treated with copaiba oil at a dose of 0.58 and 1.15 g·Kg-1. Copaiba oil was administrated orally once a day during 5 days prior and 18 days after arthritis induction. Paw volume was measured by plethysmography. Secondary lesions and the weight of adrenals, liver and lymph nodes were additionally measured. At day 19th, peritoneal cavity of anesthetized rats was exposed, blood collected from the cava vein and the liver was removed and divided into two parts: one was used for histological processing and the other used for liver homogenate preparation. Protein carbonyl groups and ROS were measured in the homogenate to evaluate liver oxidative stress. Oxidized (GSSG) and reduced (GSH) glutathione content and catalase and SOD activity were evaluated in the homogenate supernatant as antioxidant parameters. Total antioxidant capacity (TAC), thiol groups, protein carbonyl groups and mieloperoxidase (MPO) activity were also measured in the plasma. Bilirubin levels and AST, ALT and alkaline phosphatase activities were measured in the plasma to evaluate the liver damage. Morphologic and morphometric analysis was done with images from the region near the central vein of liver parenchyma. The treatment protocol was repeated three times to evaluate the hepatic metabolism. Glycogenolysis, glycolysis and gluconeogenesis were measured in the isolated perfused livers. It was additionally investigated the respiratory activity of mitochondria isolated from livers. Arthritic rats developed an intense inflammatory response to adjuvant in the injected paw and also in the contralateral paw. Animals furthermore presented low body weight gain and systemic inflammatory manifestations, as evidenced by higher plasma myeloperoxidase activity, low levels of plasma albumin, severe secondary lesions to arthritis in the tail and ears associated with increased weight of adrenals and lymph nodes. It was observed histological alterations in the liver, as sinusoid dilatation, encapsulated inflammatory foci and lower number of hepatocyte per hepatic area. Arthritic rats presented an increased oxidative stress in the plasma and in the liver, as evidenced higher levels of ROS and protein carbonyl groups in the liver, decreased activity of catalase and GSH content in the liver, higher levels of protein carbonyl groups in the plasma and decreased TAC and thiols in the plasma. Glycogenolysis and glycolysis of arthritis rats were not different, but the gluconeogenesis was 44% lower in the arthritis. In the presence of copaiba oil, paw volume was 43 and 51% lower, respectively, for arthritic rats treated at a doses of 0.58 and 1.15 mg·Kg-1 and, only at a dose of 0.58 mg·Kg-1, was able to decrease the weight of adrenals and lymph nodes between 20-50%. Copaiba oil did not modify the plasma oxidative status of arthritic rats, but it decreased the plasma myeloperoxidase activity (-30%) at a dose of 0.58 mg·Kg-1. Copaiba oil only at a dose of 1.15 mg·Kg-1 decreased the protein carbonyl groups and ROS in the liver to values close the control ones. Both doses increased the GSH content and catalase activity in the liver. Copaiba oil 1.15 g·Kg-1 also decreased the body weight gain (-45%) and number of hepatocytes (-20%) while increased the liver weight (29%) and the area of hepatocytes (13%) in arthritic and control rats. Copaiba oil 1.15 g·Kg-1 decreased the glycolysis (-65%), glycogenolysis (-58%) and gluconeogenesis (-30%) in the liver of arthritic animals. However, the gluconeogenesis was also diminished in the livers of treated control rats. The respiratory activity of isolated mitochondria was practically not modified by copaiba oil treatment. The results of the present study revealed that (I) adjuvant-induced arthritis in rats is associated to an intense inflammatory response with systemic manifestations, particularly histological and metabolic alterations in the liver; (II) copaiba oil presented a moderate anti-inflammatory effects on the arthritis induction and improved the systemic manifestation at a dose of 0.58 g·Kg-1; (III) treatment at a dose of 1.15 g·Kg-1 was effective to decrease the oxidative stress in the liver, one action that can be attributed to the stimulation in endogenous antioxidant system; (IV) treatment with copaiba oil 1.15 g·Kg-1 was not effective in improving the histological alterations in the liver of arthritic rats; (V) copaiba oil decreased the glycolysis, glycogenolysis and gluconeogenesis (-30%) in the liver of arthritic animals; however, (VI) it decreased the gluconeogenesis in the liver of control rats; (VII) copaiba oil did not modify substantially the respiratory activity in the isolated mitochondria; and finally (VIII), it caused histological alterations in the liver of control rats, which associated with the lower body weight gain, reduced gluconeogenesis in the liver and higher liver weight can indicate a possible harmful action of the oil, such as a liver cholestasis. Thus, the use of copaiba oil as an adjuvant in the treatment of rheumatoid arthritis in humans must be regarded with caution because it may additionally be harmful, specially for the liver, where great modifications were observed.