Epigallocatechin gallate attenuates fibrosis, oxidative stress, and inflammation in non-alcoholic fatty liver disease rat model through TGF/SMAD, PI3 K/Akt/FoxO1, and NF-kappa B pathways.

PURPOSE: To investigate the protective mechanisms of an 85 % pure extract of (-) epigallocatechin gallate (EGCG) in the development of fibrosis, oxidative stress and inflammation in a recently developed dietary-induced animal model of non-alcoholic fatty liver disease (NAFLD). METHODS: Female Sprague-Dawley rats were fed with either normal rat diet or high-fat diet for 8 weeks to develop NAFLD. For both treatments, rats were treated with or without EGCG (50 mg/kg, i.p. injection, 3 times per week). At the end, blood and liver tissue samples were obtained for histology, molecular, and biochemical analyses. RESULTS: Non-alcoholic fatty liver disease (NAFLD) rats showed significant amount of fatty infiltration, necrosis, fibrosis, and inflammation. This was accompanied by a significant expressional increase in markers for fibrosis, oxidative stress, and inflammation. TGF/SMAD, PI3 K/Akt/FoxO1, and NF-κB pathways were also activated. Treatment with EGCG improved hepatic histology (decreased number of fatty score, necrosis, and inflammatory foci), reduced liver injury (from ~0.5 to ~0.3 of ALT/AST ratio), attenuated hepatic changes including fibrosis (reduction in Sirius Red and synaptophysin-positive stain) with down-regulation in the expressions of key pathological oxidative (e.g. nitrotyrosine formation) and pro-inflammatory markers (e.g. iNOS, COX-2, and TNF-α). EGCG treatment also counteracted the activity of TGF/SMAD, PI3 K/Akt/FoxO1, and NF-κB pathways. Treatment with EGCG did not affect the healthy rats. CONCLUSIONS: Epigallocatechin gallate (EGCG) reduced the severity of liver injury in an experimental model of NAFLD associated with lower concentration of pro-fibrogenic, oxidative stress, and pro-inflammatory mediators partly through modulating the activities of TGF/SMAD, PI3 K/Akt/FoxO1, and NF-κB pathways. Therefore, green tea polyphenols and EGCG are useful supplements in the prevention of NAFLD.

Stereology of the thyroid gland in Indo-Pacific bottlenose dolphin (Tursiops aduncus) in comparison with human (Homo sapiens): quantitative and functional implications.

The mammalian thyroid gland maintains basal metabolism in tissues for optimal function. Determining thyroid volume is important in assessing growth and involution. Volume estimation is also important in stereological studies. Direct measurements of colloid volume and nuclear-to-cytoplasmic ratio of the follicular cells may provide important information about thyroid gland function such as hormone storage and secretion, which helps understand the changes at morphological and functional levels. The present study determined the colloid volume using simple stereological principle and the nuclear-to-cytoplasmic ratio of 4 Indo-Pacific bottlenose dolphins and 2 human thyroid glands. In both dolphin and human thyroid glands, the size of the follicles tended to be quite variable. The distribution of large and small follicles within the thyroid gland was also found to be random in both the dolphin and human thyroid gland; however, the size of follicles appeared to decrease as a function of increasing age in the dolphin thyroid gland. The mean colloid volume of the dolphin thyroid gland and human thyroid gland was 1.22×10(5) µm(3) and 7.02×10(5) µm(3) respectively. The dolphin and human subjects had a significant difference in the mean colloid volume. The mean N/C ratio of the dolphin thyroid follicular epithelia and human follicular epithelia was 0.50 and 0.64 respectively. The dolphin and human subjects had a significant difference in the mean N/C ratio. This information contributes to understanding dolphin thyroid physiology and its structural adaptations to meet the physical demands of the aquatic environment, and aids with ultrasonography and corrective therapy in live subjects.

Epigallocatechin-3-gallate (EGCG) reduces liver inflammation, oxidative stress and fibrosis in carbon tetrachloride (CCl4)-induced liver injury in mice.

The anti-inflammatory and antioxidant effects of epigallocatechin-3-gallate (EGCG) are considered important forces in attenuate liver injury and fibrosis. The aim of the study was to investigate the effect of EGCG on the expression of fibrogenic factors and whether EGCG attenuates the severity of oxidative stress and inflammatory response in chronic liver injury. Mice were administered with CCl(4) together with or without EGCG for 8 weeks (n=6-8 per group). Histopathological and biochemical analyses were carried out. The mRNA expression levels of TNF-alpha, COX-2, iNOS, alpha-smooth muscle actin (alpha-SMA), transforming growth factor (TGF-beta(1)), pro-collagen-I, matrix metalloproteinases (MMP-2, -9) and their inhibitors (TIMP-1, -2) were determined by RT-PCR. The collagen deposited in the liver was detected by Sirius Red staining. The formation of nitrotyrosine was measured as a marker of oxidative stress. The activity level of NF-kappaB and the expression level of C/EBP were also assessed. Chronic CCl(4) treatment caused liver injury, oxidative stress and nitrosative stress, and collagen accumulation in the liver. The expression levels of pro-inflammatory and pro-fibrotic mediators and the activity of NF-kappaB were increased. Treatment with EGCG significantly reduced liver injury, oxidative stress and the inflammatory response. EGCG also significantly reduced the formation of collagen in the liver, the expression of alpha-SMA and all of the assayed pro-fibrogenic markers except TIMP-2 and MMP-9. EGCG significantly attenuated the severity of CCl(4)-induced liver injury and the progression of liver fibrosis. The protective effect of EGCG may in part be a consequence of the reduction in oxidative stress and the pro-inflammatory response.