We demonstrate for the first time that exposure to therapeutic frequency ultrasound in continuous or pulsed mode is able to reduce liver damage in the context of partial hepatectomy with vascular exclusion . Importantly, this study highlighted that 0.8 MHz pulsed ultrasound-based therapy produces two effects: a) protection against I/R injury associated with decreased hepatic IL-1β and b) improved liver regeneration after 6 hours of reperfusion. These postoperative results were obtained by applying noninvasive pulsed-wave ultrasound during short periods on the right upper abdomen of the rat before and after surgery. For more than 40 years, ultrasound has been applied as a therapy that promotes healing. Additionally, ultrasound enhances several growth factors associated with angiogenesis and has been shown to reduce the inflammatory response after surgery. By applying ultrasound into tissues, the pressure wave generates heat, cavitation or mechanical forces which are ultimately responsible for the well-known biological effects of ultrasound. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay As a result of the propagation of ultrasound waves through tissues, endothelial cells and blood absorb part of the incident field, thus producing localized effects. Our results indicate a preservation of tissue structure and a reduction of tissue inflammation following I/R injury in the liver, in agreement with other studies that have shown that the ultrasound regimen also protects several tissues from I/R injury. . Ultrasound waves have previously been shown to induce the generation of growth factors (FGF and VEGF) and modulate several cytokines that play a major role in inflammation (TNFα, IL-6, IL-8, IL-1β, IL-2 ). The present study demonstrated that pulsed ultrasound increased HGF, which may be related to liver regeneration. To the best of our knowledge, no effects of ultrasound on HGF have been previously described. Furthermore, it was highlighted that the reduction in liver damage brought about by ultrasound therapy (in continuous or pulsed mode) was associated with a reduction in hepatic IL-1β levels. In addition to the anti-inflammatory effects of ultrasound, it has also been described that the damage caused by oxidative stress during post-ischemic reperfusion can be attenuated by intermittent pulses of ultrasound. In line with this, reduced formation of lipid peroxide in the peripheral blood was recorded in hamsters after the application of ultrasound waves after I/R. Under the conditions evaluated here, neither continuous nor pulsed ultrasound was able to reduce oxidative stress. It should be noted that under our conditions we evaluated markers of oxidative stress in liver tissue of rats, indicating differences in the effects of ultrasound waves depending on tissues and animal species. The results of the present study highlight different effects of ultrasound depending on the mode of application and the frequencies used. Previous studies suggest that there are differences between animal species in tissue responses to continuous and pulsed ultrasound. Continuous ultrasound causes increases in tissue temperature which can result in, among other effects, decreased pain, increased blood flow, and reduced subacute and chronic inflammation. Pulsed ultrasound has minimal thermal effects and has been found to have a number of biological effects on tissue, including accelerating soft tissue regeneration,35 and even.