Spermatogonia survival in young ram lambs following irradiation, Busulfan or thermal treatment

Spermatogonial Stem Cell Transplantation in Large Animals

Simple Summary

The spermatogonial stem cell (SSC) is the only adult stem cell in males to transmit genetic information to offspring. SSC transplantation (SSCT) is a laboratory technique to regenerate spermatogenesis in recipient males, thus can be used as a novel breeding tool to benefit animal production. Although successful SSCT in rodent models has been established, progress in realizing SSCT in large animals has been limited. Here we discuss what we learned in this area from past experiments and highlight possible directions in developing effective SSCT protocol in large animals.

Abstract

Spermatogonial stem cell transplantation (SSCT) can restore male fertility through transfer of germline between donor and recipient males. From an agricultural perspective, SSCT could be an important next-generation reproductive and breeding tool in livestock production. Current SSCT approaches in large animals remain inefficient and many technical details need further investigation. This paper reviews the current knowledge on SSCT in large animals, addressing (1) donor spermatogonial stem cell (SSC) preparation, (2) recipient male treatment, and (3) SSC injection, homing, and detection. The major studies showing unequivocal evidence of donor SSC-derived spermatogenesis in large animals (mainly in livestock for breeding purpose) are summarized to discuss the current status of the field and future directions.

Spermatogonial stem cell survival in ram lambs following busulfan treatment

To clarify the effect of busulfan on the depletion of spermatogonial stem cells (SSCs) from shal rams testis, in the first experiment, lambs were treated by intraperitoneal injection with 4 mg/kg busulfan. In the second experiment, different concentrations of busulfan (1, 2 and 4 mg/kg) were injected directly into both sides of the left testis. The testes of 8 lambs were collected by standard castration procedure for histological analysis five weeks after the treatments and the left testis of remaining lambs were collected after eight weeks and a two-time enzymatic digestion process was used to isolate SSCs. The results showed that all rams that had received intraperitoneal injections of busulfan died. But by testicular injecting of same dose of the drug, 40% of the animals died. The testicular injection of rams with 1, 2 and 4 mg/kg of busulfan resulted in a dose dependent decrease in testis size and also spermatocytes population after 5 weeks of treatments. From the results of colony formation 8 weeks after treatment with busulfan, it can be concluded that only in 1 and 2 mg/kg of busulfan, recovery of endogenous germ cells was performed. In conclusion, the results demonstrated that intra-testicular injections of busulfan (2 mg/kg) reduced spermatocytes population in ram testis within 5 weeks of treatments, and this effect was reversible within 8 weeks of injection. However, it was not recommended to inject 4 mg/kg busulfan into the peritoneal cavity or testis of lambs based on its side effects.

Thymus vulgaris Attenuates Myleran-induced Reproductive Damage by Decreasing Oxidative Stress and Lipid Peroxidation in Male Rats

Context:

Thymus vulgaris is an herbal with potent antioxidant and it has been shown to have beneficial effects during short-term administration. Myleran (MYL) is used for treatment of certain types of tumors. MYL produces free radicals and induces disturbance in sperm parameters.

Aims:

This study is designed to assess the effects of T. vulgaris against damage to the male rats' reproductive features induced by MYL.

Subjects and Methods:

Sixty-four male Wistar rats were randomly assigned into eight groups: control group; MYL (10 mg/kg) group; T. vulgaris groups (4.5, 9, and 18 mg/kg); and MYL (10 mg/kg) + T. vulgaris groups (4.5, 9, and 18 mg/kg; separately). Treatments were administered daily intraperitoneal injection for 60 days. Total antioxidant capacity, sperm factors, malondialdehyde (MDA), testosterone, and germinal layer height were analyzed.

Results:

Whole variables of MYL group decreased signifcantly compared to the control group (P < 0.05) except MDA level (which increased). The T. vulgaris and T. vulgaris + MYL treatments in all doses increased all parameters significantly except MDA level (which decreased) compared to the MYL group (P < 0.05). No significant modifications were observed in all T. vulgaris groups compared to the control group (P > 0.05).

Conclusions:

T. vulgaris reduces the poisonous properties of MYL on male reproductive factors.

Manipulation of spermatogonial stem cells in livestock species

We are entering an exciting epoch in livestock biotechnology during which the fundamental approaches (such as transgenesis, spermatozoa cryopreservation and artificial insemination) will be enhanced based on the modern understanding of the biology of spermatogonial stem cells (SSCs) combined with the outstanding recent advances in genomic editing technologies and in vitro cell culture systems. The general aim of this review is to outline comprehensively the promising applications of SSC manipulation that could in the nearest future find practical application in livestock breeding. Here, we will focus on 1) the basics of mammalian SSC biology; 2) the approaches for SSC isolation and purification; 3) the available in vitro systems for the stable expansion of isolated SSCs; 4) a discussion of how the manipulation of SSCs can accelerate livestock transgenesis; 5) a thorough overview of the techniques of SSC transplantation in livestock species (including the preparation of recipients for SSC transplantation, the ultrasonographic-guided SSC transplantation technique in large farm animals, and the perspectives to improve further the SSC transplantation efficiency), and finally, 6) why SSC transplantation is valuable to extend the techniques of spermatozoa cryopreservation and/or artificial insemination. For situations where no reliable data have yet been obtained for a particular livestock species, we will rely on the data obtained from studies conducted in rodents because the knowledge gained from rodent research is translatable to livestock species to a great extent. On the other hand, we will draw special attention to situations where such translation is not possible.