Effect of Antioxidant Treatment of Streptozotocin-Induced Diabetic Rats on Endoneurial Blood Flow, Motor Nerve Conduction Velocity, and Vascular Reactivity of Epineurial Arterioles of the Sciatic Nerve
Article Figures & Tables
Figures
- FIG. 1.
Sciatic nerve Na+/K+ ATPase activity. For these studies, control rats, diabetic rats, and diabetic rats treated with either HES-DFO (DFO) or α-lipoic acid (αLA) were used to determine sciatic nerve Na+/K+ ATPase activity, as described in research design and methods. The duration of diabetes and treatments for these studies was 3–4 weeks. Data are presented as means ± SE for a minimum of eight separate samples. Sciatic nerve Na+/K+ ATPase activity in control rats treated with HES-DFO or α-lipoic acid was 296 ± 10 (n = 3) and 260 ± 44 (n = 3) μmol ADP · g wet wt−1 · h−1, respectively. *A significant difference compared with control rats.
- FIG. 2.
Sciatic nerve sorbitol and myo-inositol content. Samples of the sciatic nerve from the animals described in Fig. 1 were used to determine the sorbitol and myo-inositol content, as described in research design and methods. Data are presented as means ± SE for a minimum of eight separate samples. *A significant difference compared with control rats; +a significant difference compared with untreated diabetic rats.
- FIG. 3.
Serum triglyceride and free fatty acid (FFA) levels. Serum collected from animals described in Fig. 1 was used to determine the triglyceride and free fatty acid levels, as described in research design and methods. Data are presented as means ± SE for a minimum of eight separate samples. *A significant difference compared with control.
- FIG. 4.
Liver and serum TBARSs. Liver and serum samples were collected from the animals described in Fig. 1 and used to determine TBARS level as described in research design and methods. Serum TBARSs in control rats treated with HES-DFO or α-lipoic acid were 4.8 ± 0.6 (n = 3) and 5.6 ± 1.2 (n = 3) μg/ml, respectively. Data are presented as means ± SE for a minimum of eight separate samples. *, A significant difference compared with control rats; +, a significant difference compared with untreated diabetic rats.
- FIG. 5.
Lens GSH level. The lens was collected from the animals described in Fig. 1 and used to determine GSH level as described in research design and methods. Data are presented as means ± SE for a minimum of eight separate samples. Lens GSH level in control rats treated with HES-DFO or α-lipoic acid was 1.4 ± 0.2 (n = 3) and 1.6 ± 0.3 (n = 3) μg/mg wet wt, respectively. *, A significant difference compared with control; +, a significant difference compared with untreated diabetic rats.
- FIG. 6.
Liver and sciatic nerve conjugated diene level. Samples of the liver and sciatic nerve were collected from the animals described in Fig. 1 and used to determine conjugated diene level as described in research design and methods. Data are presented as means ± SE for a minimum of eight separate samples. Sciatic nerve conjugated diene level in control rats treated with HES-DFO or α-lipoic acid was 2.7 ± 0.4 (n = 3) and 3.1 ± 1.5 (n = 3) μmol/mg wet wt, respectively. *, A significant difference compared with control rats.
- FIG. 7.
Detection of superoxide level in arterioles from control rats, diabetic rats, and diabetic rats treated with either HES-DFO (DFO) or α-lipoic acid (αLA). The duration of diabetes and treatments for these studies was 3–4 weeks. Fluorescent photomicrographs of confocal microscopic sections of arterioles that provide circulation to the region of the sciatic nerve from the three individual groups of animals were examined on the same day. Arterioles were labeled with the oxidative dye hydroethidine as described in research design and methods. Recordings of fluorescence were taken at identical laser and photomultiplier settings for both control rats and untreated and treated diabetic rats. Shown is a representative sample of one set of animals. This experiment was repeated three separate times on separate sets of animals on three different days with similar results.
- FIG. 8.
Determination of superoxide in the aorta using lucigenin-enhanced chemiluminescence. Samples of the aorta were collected from the animals described in Fig. 1 and used to determine superoxide level using lucigenin-enhanced chemiluminescence. Data are presented as mean RLUs ± SE for a minimum of eight separate samples. *A significant difference compared with control; +a significant difference compared with untreated diabetic rats.
- FIG. 9.
Detection of peroxynitrite in arterioles from control rats, diabetic rats, and diabetic rats treated with either HES-DFO (DFO) or α-lipoic acid (αLA). Arterioles from control rats, untreated diabetic rats, and diabetic rats treated with either HES-DFO (DFO) or α-lipoic acid (αLA) were collected and treated for determination of 3-nitrotyrosine immunostaining as described in research design and methods. Shown is a representative sample of one set of animals. This experiment was repeated four separate times with similar results.
- FIG. 10.
Determination of EBF. EBF reported as nutritive or conductance was determined for the same rats described in Table 1 and Fig. 1. EBF was determined as described in research design and methods. Data are presented as means ± SE for a minimum of eight separate samples. Nutritive EBF in control rats treated with HES-DFO or α-lipoic acid was 15.5 ± 5.6 (n = 3) and 15.3 ± 2.8 (n = 3) ml · min−1 · 100 g−1, respectively. *A significant difference compared with control rats; +a significant difference compared with untreated diabetic rats.
- FIG. 11.
Determination of MNCV. MNCV was determined for the same rats described in Table 1 and Fig. 1. MNCV was determined as described in research design and methods. Data are presented as means ± SE for a minimum of eight separate samples. MNCV in control rats treated with HES-DFO or α-lipoic acid was 54.9 ± 3.0 (n = 3) and 51.3 ± 7.2 (n = 3) m/s, respectively. *A significant difference compared with control rats; +a significant difference compared with untreated diabetic rats.
- FIG. 12.
Determination of the effect of treatment with HES-DFO or α-lipoic acid (αLA) on acetylcholine-mediated vascular relaxation in arterioles that provide circulation to the region of the sciatic nerve. Pressurized arterioles were constricted with U46619 (30–50%), and incremental doses of acetylcholine were added to the bathing solution while the steady-state vessel diameter was recorded. The number of experimental animals used in these studies was the same as that noted in Table 1. *Denotes that the response to acetylcholine was significantly attenuated in the diabetic rat; +denotes that the response to acetylcholine was significantly different compared with the untreated diabetic rats.
Tables
- TABLE 1
Change in body weight and blood glucose levels
Animal Change in body weight (g) Blood glucose mg/dl Control (n = 9) 119 ± 11 97 ± 3 Diabetic (n = 8) 4 ± 8* 424 ± 26* Diabetic + HES-DFO (n = 8) 17 ± 11* 450 ± 22* Diabetic + α-lipoic acid (n = 11) 1 ± 11* 373 ± 15* Data are means ± SE.
- *
* P < 0.05 vs. control.
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