Beneficial effects of (−)‐epigallocatechin‐3‐O‐gallate on diabetic peripheral neuropathy in the rat model

Abstract

Diabetic neuropathic pain is characterized by spontaneous pain with hyperalgesia and allodynia. We investigated whether (−)‐epigallocatechin‐3‐O‐gallate could improve diabetic neuropathic pain development through hypoglycemic, hypolipidemic, antioxidant, and anti‐inflammatory effects. Diabetes was induced in rats by streptozotocin (55 mg/kg/once) and treated with (−)‐epigallocatechin‐3‐O‐gallate (25 mg/kg/orally/once/daily/5 weeks). Diabetic rats showed an increase in serum levels of glucose, nitric oxide, triglyceride, total cholesterol, and low‐density lipoprotein‐cholesterol with a decrease in high‐density lipoprotein‐cholesterol and body weight. Also, there was an elevation in brain malondialdehyde with a marked reduction in brain levels of glutathione, superoxide dismutase, catalase, glutathione peroxidase, and glutathione‐S‐transferase. Furthermore, diabetic rats showed a clear reduction in plasma levels of insulin and an increase in plasma cytokines (interleukin‐6 and tumor necrosis factor‐α). Moreover, diabetic rats exhibited hyperalgesia as indicated by a hot plate, tail immersion, formalin, and carrageenan‐induced edema tests as well as brain histopathological changes (neuron degeneration, gliosis, astrocytosis, congestion and hemorrhage). (−)‐Epigallocatechin‐3‐O‐gallate treatment ameliorated alterations in body weight, biochemical parameters, pain sensation, and histopathological changes in brain tissue. (−)‐Epigallocatechin‐3‐O‐gallate offers promising hypoglycemic, hypolipidemic, antioxidant and anti‐inflammatory effects, which can prevent the development and progression of diabetic neuropathic pain.

Securidaca inappendiculata Polyphenol Rich Extract Counteracts Cognitive Deficits, Neuropathy, Neuroinflammation and Oxidative Stress in Diabetic Encephalopathic Rats via p38 MAPK/Nrf2/HO-1 Pathways

“…Motor and sensory nerve conduction dysfunction, numbness and chronic pain are characteristics features that have been well documented to correlate with chronic hyperglycemia ( Edwards et al, 2008 ). Previous studies have also reported increased pain sensation in diabetic animal models ( Kishore et al, 2017 ; Abo-Salem et al, 2020 ). In this study, marked decrease in nociceptive threshold in the hotplate and tail immersion test were observed in the diabetic rats, suggesting that the diabetic rats displayed increased hyperalgesia.…”

“…Diabetes has also been reported to significantly affect pain response ( Kishore et al, 2018 ; Abo-Salem et al, 2020 ). Hyperalgesia, a condition that is exemplified by extreme sensitivity to painful stimuli is one of the most often encountered complication of diabetes, and it arises due to damages to peripheral nerves ( Lee-Kubli et al, 2014 ; Hasanein et al, 2020 ).…”

Tannins in the Treatment of Diabetic Neuropathic Pain: Research Progress and Future Challenges

“…Male rats from various species such as Swiss albino (Abo-Salem et al, 2020), Sprague-Dawley (Ding et al, 2014;Addepalli and Suryavanshi, 2018), Wistar (Cui et al, 2008;Piaulino et al, 2013;Raposo et al, 2015) and albino Wistar (Baluchnejadmojarad and Roghani, 2012) were used in the majority of the studies as DNP models. Two more studies used male Swiss Webster (Raafat and Samy, 2014) and C57BL/6J mice (Jin et al, 2013), while two investigations used cell cultures of dorsal root ganglion neuron (Zhang et al, 2018) and RSC96 Schwann cells (Ding et al, 2014) as a model for DNP.…”

“…Many of the diabetes medications developed aimed to correct these problems and restore the situation by reducing the blood glucose level and increasing body weight. It has been demonstrated that taking (−) ‐Epigallocatechin‐3‐O‐gallate (EGCG) orally at a dose of 25 mg/kg for 5 weeks can lower serum blood glucose levels, improve serum lipid profiles, and increase body weight ( Abo-Salem et al, 2020 ). Other studies were done by Addepalli and Suryavanshi (2018) used catechin, Raafat and Samy (2014) used Punica granatum L. (Lythraceae) extract, and Baluchnejadmojarad and Roghani (2012) used EGCG have validated the benefits of phytochemical tannins in lowering blood glucose and increasing body weight.…”

Gene Expression Profiling of the Sciatic Nerve in Streptozotocin-Induced Diabetic Rats with Peripheral Neuropathy

“…STZ-induced diabetic rats have been widely used for the histopathological, pharmaceutical, or neurological research of experimental DPN [38][39][40][41]. Yet few studies have performed microarray experiment on the peripheral nerve tissue of DPN rats with STZ-induced diabetes.…”