The effects of rat transplantated tumor capillary permeability under microbubble enhanced diagnostic ultrasound exposure

Objective To investigate the effects of transplantated tumor capillary permeability under microbubble enhanced diagnostic ultrasound exposure.Methods Fourty eight rats were randomly divided into four groups after Walker 256 carcinomas were subcutaneousely implanted,named the control group (A),microbubbles group (B),ultrasound group (C),microbubbles and ultrasound group (D).Using Evans blue(EB) as the indicator for tumor capillary permeability,the microbubbles were injected through the vein with diagnostic ultrasound frequency as 1.75 MHz,mechanical index as 1.4.The spillover of EB was estimated under confocal laser microscope,meanwhile the contents of EB in the tumor tissues were calculated according to the standard curve and spectrophotometry.Results EB spillover was observed around the capillaries in the group D,while EB spillover was only observable on capillary in group A,B and C.The EB content was also significantly higher than those in group A,B and C.Conclusions Exposure to both diagnostic ultrasound and microbubbles results in increased capillary permeability of rat tumor tissues,which might become a potential therapeutic method on clinical chemotherapy. Key words: Ultrasonography; Microbubbles; Neoplasm transplantation; Capillary permeability; Evens blue