Assessing the anti-inflammatory effects of whole-body vibration: a meta-analysis based on pre-clinical and clinical evidences.

Am J Clin Exp Immunol 2024;13(3):68-87 www.ajcei.us /ISSN:2164-7712/AJCEI0155457 Review Article Assessing the anti-inflammatory effects of whole-body vibration: a meta-analysis based on pre-clinical and clinical evidences Yiying Wang1, Renxin Ji2, Bo Yu1 1 Department of Rehabilitation Medicine, Shanghai First People’s Hospital, Shanghai 200080, China; 2Department of Rehabilitation Therapy, Shanghai Sanda University, Shanghai 201209, China Received January 15, 2024; Accepted June 6, 2024; Epub June 25, 2024; Published June 30, 2024 Abstract: Background: Whole-body vibration (WBV) is a commonly used physical exercise for disease prevention and rehabilitation. Recent studies indicated the beneficial mechanism of WBV may be associated with its anti-inflammatory potential, however, its regulatory roles on different inflammatory mediators remained controversial. The aim of this study was to perform a meta-analysis to re-confirm the effects of WBV exercise on various inflammatory factors. Methods: The PubMed, EMBASE and Cochrane Library databases were searched up to September 2023 to collect all articles comparing WBV with control (or post-pre trials). The effect size was expressed as the standardized mean difference (SMD) and 95% confidence intervals (CI). Results: A total of 31 eligible studies were included, including 14 pre-clinical and 17 clinical studies. The meta-analysis of pre-clinical studies showed that compared with the control group, WBV exercise could significantly reduce the level of IL-6 (SMD: -1.03, 95% CI: -1.93, -0.13), TNF-α (SMD: -1.36, 95% CI: -2.54, -0.17) (for disease subgroup), IL-1β (SMD: -2.20, 95% CI: -3.24, -1.15), IFN-γ (SMD: -1.91, 95% CI: -2.71, -1.12), IL-4 (SMD: -0.71, 95% CI: -1.39, -0.03) and IL-17 (SMD: -1.32, 95% CI: -2.05, -0.59) overall. Pooling of clinical studies revealed WBV exercise significantly reduced the level of TNF-α (WBV vs control: SMD: -1.11, 95% CI: -2.16, -0.06; post vs pre: SMD: -1.29, 95% CI: -1.91, -0.67), CRP (SMD: -3.59, 95% CI: -6.36, -0.82, P = 0.011) and enhanced the level of IL-10 (WBV vs control: SMD: 2.90, 95% CI: 1.10, 4.71; post vs pre: SMD: 1.75, 95% CI: 0.64, 2.87) and IL-6 (SMD: 0.91, 95% CI: 0.31, 1.52) (healthy subgroup). Conclusion: WBV may be an effective prevention and rehabilitation tool for inflammatory diseases. Keywords: Whole-body vibration, inflammation, murine models, clinical trials, meta-analysis Introduction Physical exercise has been widely accepted as an important non-pharmacological strategy for prevention and rehabilitation treatment of several diseases [1]. However, the adherence of conventional aerobic and resistance exercise is often low (approximately 60%) in populations due to a lack of time, motivation, companionship, access to specialized facilities and poor physical conditions (such as fragility, reduced cognitive function and motor capacity) that leads to the difficulties to perform active exercise [2, 3]. These disadvantages of conventional exercise indicate the requirement of alternative intervention approaches. Whole-body vibration (WBV) involves the exposure of the entire body to mechanical oscillations while the populations stand or sit on a vibration platform [4]. The intensity of vibrations transmitted to the populations can be regulated according to their frequency (5-60 Hz), amplitude (0.5-4 mm), acceleration (0.3 g-8 g) and durations of sessions (5-15 min per session) [4]. This kind of exercise can be assessed at home, in the local community or at rehabilitation units; requires little effort and motivation from the practitioner; needs a low exposure time and is suitable for individuals whom exercise is inconvenient. WBV is therefore suggested as a better alternative exercise. WBV had been applied for rehabilitation treatment of patients with knee osteoarthritis (OA) [5], cerebral palsy [6], metabolic syndrome [7], stroke [8], Parkinson [9] and prevention of falls and fractures in middle-aged and senior people [10, 11], the improvement https://doi.org/10.62347/LLGY4023 Anti-inflammatory effects of whole-body vibration effects of which were confirmed in these metaanalysis studies. Although the beneficial mechanism of physical exercise may be complex, it may be associated with its anti-inflammatory and immunomodulatory potential [12-15]. Khosravi et al. found exercise training significantly decreased proinflammatory markers in cancer survivors, especially C-reactive protein [CRP: standardized mean differences (SMD): -0.5, 95% confidence intervals (CI): -0.9, -0.06, P = 0.025] and tumor necrosis factor (TNF-α: SMD: -0.3, 95% CI: -0.5, -0.06, P = 0.004) [15]. Compared with pretreatment, TNF-α levels were found to be significantly decreased in adult individuals with multiple sclerosis after regular exercise intervention (SMD: -0.51, 95% CI: -0.91, 0.11, P = 0.01) [13]. CRP was confirmed to be reduced in knee OA patients at 6-18 weeks after regular exercise therapy [14]. These findings from meta-analyses implied WBV, as an exercise model, may also function by changing the expression and secretion of inflammation-related mediators. This hypothesis had been identified in several pre-clinical and clinical studies. For example, Kerr et al. found WBV intervention significantly reduced the levels of interleukin (IL)6, TNF-α and interferon-γ (IFN-γ) in both female and male stroke model mice [16]. Chen et al. reported WBV treatment inhibited the increase of the IL-1β and TNF-α in the brain sections of traumatic brain injury model mice [17]. Wang et al. demonstrated that regardless of low, middle or high frequency, WBV was effective in decreasing the expression of IL-1β in an early knee OA rat model [18]. Rodriguez-Miguelez et al. detected the TNF-α protein content was lowed, while IL-10 mRNA content and protein concentration increased in the WBV training group compared with the control elderly subjects [19]. Seefried et al. found compared with the baseline value, the level of CRP was significantly lower in maintenance hemodialysis patients after WBV intervention [20]. Oh et al. reported WBV exercise for patients with nonalcoholic fatty liver disease decreased the levels of TNF-α and CRP by 50.8% and 14.5%, respectively (P < 0.05) [21]. However, some studies showed no benefit of WBV on influencing the pro-inflammatory factors IL-1β, IL-6, IL-10, IFN-γ or TNF-α [22-25]. Even, Yu et al. found low-frequency vibration promoted the production of TNF-α to increase cartilage degeneration in 69 knee OA [26]. These results suggested the antiinflammatory mechanisms of WBV remained inconclusive. Herein, this study was to perform a meta-analysis of all published studies to re-confirm the effects of WBV exercise on inflammatory factors in healthy or pathological model animals or human subjects. This study may provide a theoretical basis for guiding WBV training as a promising non-pharmacological rehabilitative and prevention method, particularly for inflammatory diseases. Materials and m (...truncated)