Effect of Shock Wave on Vascular Lesions in Diabetic Rats.

BACKGROUND: Diabetes is one of the most common diseases in today's society. Diabetes can cause multiple vascular lesions in the body, renal insufficiency, blindness, and so on. However, the evidence concerning the role of extracorporeal shock wave therapy in diabetic vascular disease is insufficient. OBJECTIVES: Observation of the effect of shock wave on vascular lesions in diabetic rats. STUDY DESIGN: This study used an experimental design. SETTING: The research took place in the laboratory research center at The Third Military Medical University. METHODS: Eighteen healthy adult male Sprague Dawley rats were randomly divided into 3 groups: normal control group (group A), diabetic group (group B), and diabetes + shock wave treatment group (group C). Groups B and C were established by intraperitoneal injection of streptozotocin 60 mg/kg to demonstrate a diabetic rat model. Shock wave treatment was performed on the left lower extremity femoral artery in group C for 1 week (T1), 2 weeks (T2), 3 weeks (T3), and 4 weeks (T4) while the other 2 groups were reared normally. At the end of T4 shock wave treatment, the femoral arteries of each group were observed under an electron microscope. The expression of vascular endothelial growth factors (VEGF), endothelial nitric oxide synthase (eNOS), and angiotensin type 1 (AT1) were measured by western blot, and the changes of VEGF expression were detected by real-time polymerase chain reaction. RESULTS: The VEGF and eNOS in group C were higher than those in group B (P < 0.05). The AT1 of the rats in the B and C groups was significantly higher than that in the A group (P < 0.05), but the C group was significantly lower than the B group (P < 0.05). After shock wave therapy, the surface of vascular endothelium in group C was flatter and smoother than that in group B, and the endothelial basement membrane and foot process were relatively tight. LIMITATIONS: Potential mechanisms that underlie the relationship between vascular dysfunction and diabetic neuropathy pain were not examined in this study. CONCLUSIONS: Shock wave may promote the formation of new blood vessels and improve vasomotor function by upregulating VEGF, eNOS, and downregulation of AT1 in diabetic rats and improve the damage of blood glucose to blood vessels to some extent. KEY WORDS: Shock wave, diabetic rats, vascular dysfunction, neovascularization.

[Effects and molecular mechanisms of the biological action of weak and extremely weak magnetic fields].

A number of effects of weak combined (static and alternating) magnetic fields with an alternating component of tens and hundreds nT at a collinear static field of 42 microT, which is equivalent to the geomagnetic field, have been found: the activation of fission and regeneration of planarians Dugesia tigrina, the inhibition of the growth of the Ehrlich ascites carcinoma in mice, the stimulation of the production of the tumor necrosis factor by macrophages, a decrease in the protection of chromatin against the action of DNase 1, and the enhancement of protein hydrolysis in systems in vivo and in vitro. The frequency and amplitude ranges for the alternating component of weak combined magnetic fields have been determined at which it affects various biological systems. Thus, the optimal amplitude at a frequency of 4.4 Hz is 100 nT (effective value); at a frequency of 16.5 Hz, the range of effective amplitudes is broader, 150-300 nT; and at a frequency of 1 (0.5) Hz, it is 300 nT. The sum of close frequencies (e.g., 16 and 17 Hz) produces a similar biological effect as the product of the modulating (0.5 Hz) and carrying frequencies (16.5 Hz), which is explained by the ratio A = A0sin omega1t + A0sin omega2t = A0sin(omega1 + omega2)t/2cos(omega1 - omega2)t/2. The efficiency of magnetic signals with pulsations (the sum of close frequencies) is more pronounced than that of sinusoidal frequencies. These data may indicate the presence of several receptors of weak magnetic fields in biological systems and, as a consequence, a higher efficiency of the effect at the simultaneous adjustment to these frequencies by the field. Even with consideration of these facts, the mechanism of the biological action of weak combined magnetic fields remains still poorly understood.