Fuzi Attenuates Diabetic Neuropathy in Rats and Protects Schwann Cells from Apoptosis Induced by High Glucose

Jing Han,Chun Li,Shuang Zhao,Beibei Wang,Yonggang Liu,Yan Wu,Peng Tan,Yong Wang,Zhiyong Li,Rajesh Mohanraj

doi:10.1371/journal.pone.0086539

Jing Han, Chun Li + Show 8 more

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https://doi.org/10.1371/journal.pone.0086539

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Abstract

Radix aconite lateralis preparata (Fuzi), a folk medicine, has long been used for the treatment of diabetes and paralysis in China. We examined the effect of Fuzi alone on diabetic rats and Schwann cells in high glucose and the components responsible for its activity. The major constituents of FZE were identified by HPLC-MS/MS data. Male Sprague Dawley rats (n = 36) were randomly divided into control, diabetic, FZE 1.75 g/kg, FZE 3.50 g/kg, FZE 7.00 g/kg, and methylcobalamin groups. After two weeks treatment, nerve conduction velocity and paw withdrawal latency were measured. In vitro, the Schwann cells were grouped according to exposure: normal glucose (NG), normal glucose plus mannitol (NG+M), high glucose (HG), and HG plus different concentrations of FZE (0.1 µg/ml, 1.0 µg/ml, and 10.0 µg/ml). Oxygen free radicals and apoptosis were evaluated through DCFH2DA, DHE and annexin-PE/7-AAD assay, respectively. Apoptosis factors (Bax, Bcl-2, CytoC, caspase-3, and caspase-9) were analyzed using immunofluorescence. Nine alkaloids were identified. The results from animal model showed that FZE was effective in accelerating nerve conduction velocity and shortening paw withdrawal latency in diabetic rats. And in vitro, FZE was also found to protect Schwann cells against high glucose injury. FZE could significantly decrease the apoptotic ratio, superoxide anion and peroxide level. Furthermore, the apoptosis factors, including Bax, Bcl-2, CytoC, caspase-3, and caspase-9 were ameliorated in FZE treated groups. The HPLC-MSn method is simple and suitable for the identification of alkaloids in Fuzi. FZE has a protective effect in diabetic neuropathic rats, which is probably achieved by the antiapoptotic effect of FZE on Schwann cells. Apoptosis factor data imply that FZE protected Schwann cells through the mitochondria pathway. Alkaloids are major components contributing to the protective effect.

Highlights

Diabetes mellitus is one of the most serious problems across the World. 347 million people worldwide have suffered from diabetes [www.who.org]
Disorders of nerve function include slowing in nerve conduction velocity and abnormal thermal perception followed by axonal degeneration, paranodal demyelination and loss of myelinated fibers [2,3]
We found that the level of peroxide increased within 48 h of high glucose (HG) stimulation (Figure 3), while the increase was not significant as mannitol was added to the normal glucose (NG) medium

Summary

Introduction

Diabetes mellitus is one of the most serious problems across the World. 347 million people worldwide have suffered from diabetes [www.who.org]. Diabetes mellitus is one of the most serious problems across the World. 347 million people worldwide have suffered from diabetes [www.who.org]. Diabetes can damage the heart, blood vessels, eyes, kidneys, and nerves. WHO projects that diabetes will be the 7th leading cause of death in 2030 [www.who.org]. The prevalence of neuropathy in diabetic patients is about 30%, whereas up to 50% of patients will certainly develop neuropathy during their disease [1]. Disorders of nerve function include slowing in nerve conduction velocity and abnormal thermal perception followed by axonal degeneration, paranodal demyelination and loss of myelinated fibers [2,3]. Diabetic peripheral neuropathy (DPN) has been a major cause of morbidity and mortality, and is a leading risk for foot ulceration and eventual limb amputation

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