- The Effect of Alpha-Lipoic Acid on the Protection of Epidermal Nerve Fibers and Microcapillaries in the Streptozotocin-Induced Diabetic Rats.
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Ming Han Piao, Heung Yong Jin, Sun Kyung Song, Seun Mi Kang, So Young Kim, Ji Hyun Park, Hong Sun Baek, Tae Sun Park
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Korean Diabetes J. 2007;31(6):488-497. Published online November 1, 2007
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DOI: https://doi.org/10.4093/jkda.2007.31.6.488
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Abstract
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- BACKGROUND
Diabetic neuropathy is associated with risk factors for macrovascular diseases and other microvascular complications. Alpha-lipoic acid (ALA) administration has been reported to improve metabolic abnormalities and ameliorate peripheral polyneuropathy in diabetic patients. In addition, ALA improves endoneurial nutritive neural blood flow and nerve conduction velocity in diabetic rats. But it is not clear whether ALA has a preservation effect on microvasculature in addition to the effect on intraepidermal nerve fibers (IENFs). We investigated the effect of ALA on intraepidermal nerve fiber density (numbers/mm) and cutaneous capillary length in streptozotocin-induced diabetic rats. METHODS: The rats were randomly divided into 3 groups: diabetes without diet control, diabetes with diet control, and diabetes with ALA treatment. Diabetes was induced by a single intraperitoneal injection of streptozotocin (60 mg/kg) and the effect of ALA treatment was assessed by IENF immunostained with protein gene product 9.5 and by quantification of total cutaneous capillary length with mouse anti-rat reca-1 immunostaining. RESULTS: The value of IENF density significantly increased in ALA treatment group compared with other groups (P < 0.05). Quantification of microvascularity was also significantly increased in ALA treatment group compared with other groups (P < 0.05). CONCLUSION: The results of this study suggest that ALA administration in diabetic rats may be beneficial in the prevention of peripheral neuropathy associated with improvement of microvascularity. And the symptomatic amelioration after ALA treatment may be attributed to this morphological improvement.
- The Effects of Alpha-Lipoic Acid on Epidermal Nerve Preservation in the Diabetic Neuropathy of OLETF Rats.
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Ming Han Piao, Ji Hyun Park, Hong Sun Baek, Tae Sun Park
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Korean Diabetes J. 2006;30(3):170-176. Published online May 1, 2006
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DOI: https://doi.org/10.4093/jkda.2006.30.3.170
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Abstract
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- BACKGROUND
Alpha-Lipoic acid (ALA) administration has been reported to ameliorate some of symptoms of peripheral polyneuropathy in diabetic patients and to improve endoneurial nutritive neural blood flow and nerve conduction velocity in diabetic rats. But it is not clear whether ALA has the preservation effect on epidermal nerve fibers (ENFs) density. METHODS: We tested the efficacy of ALA in preserving current perception thresholds (CPTs) and ENFs (numbers/mm) in OLETF (Otsuka Long-Evans Tokushima Fatty) rats, an animal model of type 2 diabetes, which were fed with sucrose until diabetes mellitus developed. Thereafter, one group of OLETF rats was fed with ALA and the other was not for 40 weeks. Diabetic rats were administered with ALA (80 mg/kg of body weight/day) by oral feeding for 40 weeks. The effect of ALA treatment on ENFs preservation was assessed by protein gene product 9.5 immunostaining. Quantification of neuropathic symptoms on the dorsum of hind paws of rat was measured by CPT test every 4 weeks. RESULTS: Numbers of ENF significantly decreased in OLETF rats fed without ALA compared with OLETF rats fed with ALA (P < 0.01). The thresholds at 2000, 250 and 5 Hz in OLETF rats fed with ALA did not increased and OLETF rats without ALA significantly increased at 80 weeks (P < 0.01). CONCLUSION: These observations suggest that administrations of ALA may be useful for preserving ENFs and CPTs in OLETF rats dorsum of hind paws skin.
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