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Abstract

Introduction

Protocol

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References

Developmental Biology

An In Vivo Method to Study Mouse Blood-Testis Barrier Integrity

Published: December 2nd, 2018

DOI:

10.3791/58512

1State Key Laboratory of Reproductive Medicine, Nanjing Medical University, 2Center for Reproductive Medicine, Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China
* These authors contributed equally

Here, we present a protocol to assess the blood-testis barrier integrity by injecting inulin-FITC into testes. This is an efficient in vivo method to study blood-testis barrier integrity that can be compromised by genetic and environmental elements.

Spermatogenesis is the development of spermatogonia into mature spermatozoa in the seminiferous tubules of the testis. This process is supported by Sertoli cell junctions at the blood-testis barrier (BTB), which is the tightest tissue barrier in the mammalian body and segregates the seminiferous epithelium into two compartments, a basal and an adluminal. The BTB creates a unique microenvironment for germ cells in meiosis I/II and for the development of postmeiotic spermatids into spermatozoa via spermiogenesis. Here, we describe a reliable assay to monitor BTB integrity of mouse testis in vivo. An intact BTB blocks the diffusion of FITC-conjugated inulin from the basal to the apical compartment of the seminiferous tubules. This technique is suitable for studying gene candidates, viruses, or environmental toxicants that may affect BTB function or integrity, with an easy procedure and a minimal requirement of surgical skills compared to alternative methods.

Mammalian spermatogenesis is considered a highly structured process that encompasses spermatogonial self-renewal and differentiation through spermatocytes into haploid spermatozoa via mitosis, meiosis, and spermiogenesis, during which dramatic biochemical and morphological changes occur. Developing germ cells are progressively transported from the base of the seminiferous tubule toward the lumen. This process is regulated by cell-cell contacts between germ cells and Sertoli cells1,2. Adjacent Sertoli cells form the BTB that is located near the base of the seminiferous tubule. The BTB physically divides the epi....

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All performed animal experiments have been approved by the Nanjing Medical University committee. Male C57BL/6 mice were kept under controlled photoperiod conditions and were supplied with food and water.

1. Preparations

  1. Microinjection capillaries
    1. Use microinjection capillaries with an outer diameter, inner dimeter, and length of 1.0 mm, 0.8 mm, and 10.0 cm, respectively.
    2. Pull glass capillaries with a capillary puller (Fig.......

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The experimental set-up for performing the BTB integrity assay is shown in Figure 1. Pull and sharpen microinjection capillaries with a capillary puller and micropipette beveler, respectively (Figure 1A and 1C). The thermostatic heater and equipment for microinjection are illustrated in Figure 1B and 1D.

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Spermatogenesis takes place in the seminiferous epithelium and is a highly ordered and dynamic process that is governed by germ cells and somatic cells (e.g., Sertoli cells)13. The BTB structure, which is constructed by Sertoli cells, divides the seminiferous epithelium into a basal and an apical compartment. The development of meiotic and haploid germ cells occurs in the apical compartment which forms an immunological barrier14.

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This work was supported by the National Key R&D Program of China (2016YFA0500902), the National Natural Science Foundation of China (31471228, 31771653), the Jiangsu Science Foundation for Distinguished Young Scholars (BK20150047), the Natural Science Foundation of Jiangsu Province (BK20140897, 14KJA180005) and the Innovative and Entrepreneurial Program of Jiangsu Province to K.Z.

....

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Name Company Catalog Number Comments
Capillary puller  SUTTER INSTRUMENT (USA) P-97
10x PBS Hyclone (USA) SH30258.01 dilution to 1× in ddH2O
4’,6-diamidino-2-phenylindole (DAPI) Sigma (USA) F6057
Adhesion microscope slides CITOGLAS (China) 80312-3161
Cadmium chloride Sigma (USA) 655198-5G
Confocal microscope Zeiss (Germany) LSM700
Dust-free paper Kimberly-Clark (USA) 34120
Inulin-FITC Sigma (USA) F3272
Microinjection capillaries Zhengtianyi (China) BJ-40 1.0 mm × 0.8 mm  × 100 mm
Micropipette beveler NARISHIGE (JAPAN) EG-400
OCT SAKURA (JAPAN) 4583
Paraformaldehyde Sigma (USA) P6148
Pentobarbital sodium Merck (Germany) P11011
Shaver  Yashen (China)
Stereo microscope Nikon (JAPAN) SMZ1000
Sucrose  Sangon Biotech (China) A610498
Surgical instruments Stronger (China) scissors, forceps, needle holder
Syringe KDL (China) 20163150518 0.45 mm × 0.16 mm RW LB
thermostatic heater KELL (Nanjing, China) KEL-2010
10x TBS, pH 7.6
0.2 M Tris Sangon Biotech (China) A600194
1.37 M Nacl Sangon Biotech (China) A610476

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