The histopathological and biochemical effects of green tea extract on the liver of high-fat diet and streptozotocin diabetic female rats

Abstract

ObjectiveTo evaluate the histopathological and biochemical effects of green tea extract on the liver tissues of high-fat diet and streptozotocin diabetic female rats. Methods Eighty adult female rats weighing 150-200 g were taken for the study and divided into four groups: group I (control nondiabetic group), group II (high-fat diet and nondiabetic), group III (high-fat diet and diabetic), and group IV (high-fat diet and diabetic, treated with green tea extract with a concentration of 1.5% in drinking water for 4 weeks), with each group comprising 20 rats (n = 20). Non-insulin-dependent diabetes was induced by a combination of high-fat diet and single intraperitoneal injection of streptozotocin (25 mg/kg body weight). Biochemical estimation of fasting blood glucose, fasting insulin (FINS), homeostasis model assessment of insulin resistance (HOMA-IR) index, and plasma alanine transaminase was carried out. The livers of the rats were collected for examination of clinical biochemistry, which includes measuring levels of tissue malondialdehyde (MDA) and reduced gluthione (GSH), and were studied histopathologically by light and electron microscopy. ResultsBody weight, FINS, and the HOMA-IR index were increased in the high-fat diet and nondiabetic group. Body weight, fasting blood glucose, FINS, and the HOMA-IR index were increased in the high-fat diet and diabetic group, but were significantly reduced in the high-fat diet and diabetic group treated with green tea extract. The level of MDA was significantly increased, whereas the level of GSH was significantly decreased in the liver of high-fat diet and diabetic rats; however, the level of MDA was significantly decreased, whereas the level of GSH was significantly increased in the liver of the high-fat diet and diabetic rats treated with green tea extract. Liver histopathology of non-insulin-dependent diabetes rats showed pathological changes. However, treatment with green tea extract attenuated the histopathological changes and corrected the biochemical parameters mentioned above. ConclusionGreen tea extract could potentially attenuate the hepatic injury induced by high-fat diet and streptozotocin as it has the capacity to scavenge free radicals, protect against oxidative stress, improve antioxidant enzyme activities, and exert an antidiabetic effect.

Effects of tea polyphenols and EGCG on glucose metabolism and intestinal flora in diabetic mice fed a cornstarch-based functional diet

“…For example, EGCG act as an inhibitor, which can suppress the hydrolysis of starch by binding to active site of α-amylase and α-glucosidase (Zhang et al, 2018a;Li et al, 2018). EGCG can accelerate the utilization of glucose through attenuating insulin signalling blockade (Lin & Lin, 2008;Bose et al, 2008), protect pancreatic islet cells (Song et al, 2003), and protect some other important organs, like kidney (Yoon et al, 2014;Cai et al, 2013;Periandavan et al, 2017) and liver (El-Mahalaway et al, 2013). EGCG also can reduce the absorptive of glucolipid in intestine tract (Nakai et al, 2005;Li et al, 2018), down-regulate the expression of sodiumdependent glucose cotransporter 1 (Hossain et al, 2002), promote glucose transporter 4 translocation in skeletal muscle (Ueda et al, 2008), attenuate insulin signaling blockade (Lin & Lin, 2008) etc.…”