Over-expression of CXCR4, a stemness enhancer, in human blastocysts by low level laser irradiation

Background and aim: the key role of chemokine receptor cxcr4 in themaintenance of stemness property of stem cells has been shown recently. the lowlevel laser irradiation (llli) is being used currently in a wide variety of clinicalcases as a therapeutic tool for wound healing, relieving pain and destroying tumorcells. the aim of this study was to evaluate the effect of llli mimicking lowlevel laser therapy (lllt) on the expression level of cxcr4 gene a few hoursafter irradiation on human blastocysts.methods: after the development of human embryos to the first grade blastocyststage, they were irradiated with a low power ga-al-as laser at a continuouswavelength of 650 nm and a power output of 30 mw. total rna of the irradiatedblastocysts and control groups was isolated in groups of 1x2 j/cm2, 2x2 j/cm2, 1x4j/cm2 and 2x4 j/cm2 llli. specific real-time pcr primers were designed toamplify all the two cxcr4 isoforms yet identified. rna amplifications weredone for all groups.results: we showed for the first time that llli makes the human blastocysts toincrease the expression level of cxcr4 a few hours after irradiation. moreover, itwas shown that two irradiation doses with one day interval can cause a significantincrease in cxcr4 expression level in human blastocysts.conclusion: this study revealed that llli could be a proliferation motivator forembryonic cell divisions through enhanced over-expression of cxcr4 level.