Green tea extract improves the oxidative state of the liver and brain in rats with adjuvant-induced arthritis

Abstract

The purpose of the study was to evaluate the possible effects of the administration of a green tea extract on the oxidative state of the liver and brain of adjuvant-induced arthritic rats, a model for human rheumatoid arthritis. Daily doses of 250 mg kg(-1) (59.8 mg catechins per kg) for 23 days were administered. This treatment produced significant diminutions in protein and lipid damage in liver, brain and plasma. It also diminished the tissue ROS contents and increased the antioxidant capacity of the plasma. The antioxidant defenses, which are diminished by arthritis, were improved by the green tea treatment, as revealed by the restoration of the GSH and protein thiol levels and by the strong tendency for normalizing the activities of the antioxidant enzymes. The activity of glucose 6-phosphate dehydrogenase, which is increased by arthritis in the liver, was also almost normalized by the treatment. In conclusion, it can be said that green tea consumption is possibly beneficial for the liver and brain of patients suffering from rheumatoid arthritis because it attenuates the pronounced oxidative stress that accompanies the disease and, thus, diminishes the injury to lipids and proteins in both liver and brain. There are also indications that, in the liver, the green tea can contribute to normalize the metabolic functions that are substantially modified by arthritis. For example, the green tea normalized the activity of glucose 6-phosphate dehydrogenase, a key enzyme of an important metabolic route (pentose monophosphate pathway). It is expected that the green tea treatment is equally able to normalize the activity of other enzymes (e.g., glucokinase and glucose 6-phosphatase), a hypothesis to be tested by future work.

Yerba mate aqueous extract improves the oxidative and inflammatory states of rats with adjuvant-induced arthritis

“…Unsurprisingly, the results obtained in the present study with Ilex paraguariensis are very similar to the results obtained in a previous study of our group with Camellia sinensis (green tea). 43 The green tea extract improved the oxidative state of the adjuvant-induced arthritic rats by affecting practically the same parameters in the liver, brain and plasma as the yerba mate extract: diminution of ROS contents, diminution of damage to proteins and lipids and increases in the antioxidant defenses. 43 There are also studies indicating antiinflammatory actions for green tea and green tea components.…”

“…43 The green tea extract improved the oxidative state of the adjuvant-induced arthritic rats by affecting practically the same parameters in the liver, brain and plasma as the yerba mate extract: diminution of ROS contents, diminution of damage to proteins and lipids and increases in the antioxidant defenses. 43 There are also studies indicating antiinflammatory actions for green tea and green tea components. 44,45 These and other similarities certainly reinforce the parallelism of both species as medicinal plants worldwide.…”

Abnormal Glucose Metabolism in Rheumatoid Arthritis

“…Several studies have shown that the reactive oxygen species (ROS) participate in the generation of RA [59, 60]. High level of ROS in the liver of adjuvant-induced arthritis in rats seems to be resulting from both a deficient antioxidant defense and a stimulated prooxidant system [61, 62]. It has been reported that the livers of collagen induced arthritis rats exhibited a higher oxygen consumption, and the efficiency of mitochondrial energy transduction did not decrease [63].…”

Evaluation of liposomal carnosine in adjuvant arthritis

“…RA is not a disease typically involving the CNS, but brain dysfunctions occur in 20 to 30% of rheumatic patients (Appenzeller et al 2004). There are only few studies describing oxidative stress and brain damage during experimental arthritis such as AA (Skurlova et al 2010;Skurlova et al 2011;de Almeida Gonçalves et al 2015). Carnosine is accumulated in excitable tissues (brain, heart and skeletal muscles) of vertebrates in large amounts (Abe 1995).…”