Effect Of Infrasound On The Growth Of Mice Colorectal Carcinoma

Surgery, radiotherapy, and chemotherapy are the three major cancer therapeuticstrategies, radical surgery is the most effective management for these patients atpresent. But cancer invasive and metastasis are the commonest form of recurrence andthe most important cause of death following surgical treatment. The comprehensivetreatment is also not showed promising results. Therefore, it is the urgent taskssearching new therapy, to improve the comprehensive treatment and the prognosis,Infrasound is a mechanical vibration wave with frequency between0.0001and20Hz，which is roughly the lower-frequency cut off for the human audiogram. The harmfulinfrasound effect of biology is associated with its frequency, sound pressure andexposure time; but it also can produce beneficial biology effects. In recent ten years,infrasound is more and more interesting by medical and life science field. The researchrelated to tumor is still few, although infrasound has been applied to diagnosis andtreatment of disease. This study investigated the effect of the infrasound on CT26cellboth in vitro and in vivo.1. Effect of infrasound on the growth of mice colorectal carcinoma in vitro: mice coloncarcinoma cell CT26was cultured, and divided to three groups of control group,8Hz/130dB group and16Hz/130dB group; each groups were divided into7groupsaccording to exposure days:1d,2d……6d,7d group. The CT26cells were exposed toinfrasound environment with2h a day for1to7days according to different sub groups. Cell proliferation activity of CT26was measured after infrasound exposure by MTTassay. The results showed: cell proliferation activity between the two infrasoundexposure groups and control group are significantly different (P <0.05) for culture3to6days. The proliferation of CT26in vitro can be inhibited after8Hz/130dB and16Hz/130dB infrasound exposure.2. Effect of infrasound on the growth of mice colorectal carcinoma in vivo: BALB/cmice subcutaneous transplantation colon tumor models were established, and dividedinto three groups: control group,8Hz/100dB group and16Hz/100dB group. Everygroup was exposed to infrasound environment2h a day for7days. The blood samplesof mice were obtained and serum CEA levels were measured by enzyme linkedimmunosorbent assay (ELISA method), at the7thday. Obtained implanted tumor andmeasured tumor weight, volume, and calculated the inhibition rate of implanted tumorsat the7thday. Observed the changes of transplantation tumor morphological andhistological with microscope. The expression of Caspase-3protein were measured bythe immunohistochemistry method; The results showed:①Necrosis was observed inboth8Hz/100dB and16Hz/100dB groups;②Caspase-3expression was higher in16Hz/100dB group than that in control group (P <0.05);③serum CEA level was lowerin16Hz/100dB group than that in control group (P <0.05).④For tumor volume,weight, there were no significant inhibition among three groups (P>0.05).In conclusion:①The growth of CT26in vitro can be inhibited after8Hz/130dB and16Hz/130dB infrasound exposure.②Necrosis of tumor cells was observed after8Hz/100dB and16Hz/100dB infrasound exposure.③It can promote apoptosis oftransplanted tumor cells after16Hz/100dB infrasound exposure;④Serum CEA leveldecreased which indicates that infrasound might inhibit the growth of transplantedtumor cells.