Oogonium transplantation of Monopterus albus

【Objective】To determine whether the oocyte of Monopterus albus could migrate and integrate into the reproductive ridge of zebrafish，and lay a foundation for the study of the allogenic reproductive pathway of M. albus. 【Method】Oocyte of M. albus was prepared by enzyme digestion method. Reproductive cells were labeled with PKH26 and microinjected into recipient zebrafish embryos. The migration，integration and proliferation of donor reproductive cells in the recipient were tracked under fluorescence microscope. The development of transplant recipients was detected by histomorphology；semi-quantitative PCR and fluorescence in situ hybridization detection techniques were used to detect the expression of the marker gene nanos3 mRNA in the oogonium of the recipient zebrafish embryos. 【Result】After the ovaries of M. albus were digested with protease，the concentration of cell suspension isolated was 2.4×10⁶ cells/mL， and was yellow-orange under red fluorescence after PKH26 staining. Fluorescence tracing PKH26 labeled donor oocytes showed that donor oocytes were detected at 0，12，24 and 48 hpt in zebrafish embryos，and migrated to the recipient reproductive crest for integration and proliferation. At 72 hpt，the fluorescence signal of the recipient zebrafish was lost. The results of histomorphology showed that the cytoplasm structure of 48 hpt was loose when the eel oocytes were injected into the recipient zebrafish embryos，and the germ cells migrated from the animal pole to both ends，and differentiated into tissues. There was no great difference between the recipient zebrafish transplanted with 72 hpt and 30 dpt and the control zebrafish. Semi-quantitative PCR results showed that donor germ cell marker gene nanos3 was expressed in recipient fish at 48 hpt，and donor germ cell marker gene nanos3 was weakly expressed in recipient fish at 72 hpt and 30 hpt. Fluorescence in situ hybridization technique indicated that gene nanos3 was expressed in zebrafish transplanted at 48 hpt， 72 hpt and 30 dpt.【Conclusion】The oogonia of M. albus still exists in the recipient zebrafish embryo at 48 hpt，but no oogonia of M. albus was detected in the recipient zebrafish embryo at 72 hpt，that is，the oogonia of M. albus migrates in the zebrafish receptor and finally integrates into the reproductive ridge，but can not survive after the zebrafish membrane is formed. In order to improve the survival and differentiation rate of transplantated oogonia of M. albusgerm，fishes with closer relatives or germplasm with gonadal sterility should be selected as recipients.