OCT Based Insect Embryonic Development 3D In Vivo Monitoring And Microcirculation Imaging

Acquire accurate knowledge of insect embryonic development can not only prevention and control their harmful effects of insects,but also make better use of them,discover their potential value.In vivo visualization of embryos is essential for studying insect embryonic development,however,common stereo microscopes and histological sections are usually invasive and time-consuming,and the analysis of each developmental stage usually requires a large sample size.In addition,the original structure of the embryo is easily lesion when it is fixed.Therefore,a real-time non-invasive insect embryo imaging method with high resolution is very necessary.Optical coherence tomography(OCT)technology is a novel imaging method with characteristics of high resolution,real-time and non-invasive.It uses the coherence characteristic of light to detect backscattered light interference signals to achieve non-invasive tomography in the depth direction of the sample.OCT can non-invasively and real-time record the dynamic changes in the development of biological embryo.The application of OCT in the insect field mainly focused on the dorsal vascular monitoring in the postembryonic development stage.Therefore,it is necessary to analyze insect embryos of different ages to establish a complete development process.In this paper,we observed the embryonic development of Locusta migratoria manilensis(Meyen)in vivo using OCT for the first time,and recorded the 3D morphological changes of the Locusta embryo at different stages.In the whole observation processes the phenomenon of embryo revolution and embryo torsion was observed,furthermore,the pulsation of the Dorsal vascular in the embryonic development was also observed.The beating amplitude of the contraction and relaxation of the dorsal vascular and the beat frequency of dorsal blood vessels in different embryonic development stages were quantified for the first time.The speckle variance contrast imaging algorithm was studied.In order to enhance the imaging quality,the OCT speckle variance micro-angiography algorithm was weighted and applied to the circulatory system development of insect embryos.OCT images of insect embryos were collected and processed by the weighted speckle variance algorithm to obtain three-dimensional microcirculation images of silkworm embryo.