Gonadal status of male recipient mice influences germ cell development in immature buffalo testis tissue xenograft

Abstract

Growth and development of immature testis xenograft from various domestic mammals has been shown in mouse recipients; however, buffalo testis xenografts have not been reported to date. In this study, small fragments of testis tissue from 8-week-old buffalo calves were implanted subcutaneously onto the back of immunodeficient male mouse recipients, which were either castrated or left intact (non-castrated). The xenografts were retrieved and analyzed 12 and 24 weeks later. The grafted tissue survived and grew in both types of recipient with a significant increase in weight and seminiferous tubule diameter. Recovery of grafts from intact recipients 24 weeks post-grafting was significantly lower than that from the castrated recipients. Seminal vesicle indices and serum testosterone levels were lower in castrated recipients at both collection time points in comparison to the intact recipients and non-grafted intact mouse controls. Pachytene spermatocytes were the most advanced germ cells observed in grafts recovered from castrated recipients 24 weeks post-grafting. Complete spermatogenesis, as indicated by the presence of elongated spermatids, was present only in grafts from intact recipients collected 24 weeks post-grafting. However, significant number of germ cells with DNA damage was also detected in these grafts as indicated by TUNEL assay. The complete germ cell differentiation in xenografts from intact recipients may be attributed to efficient Sertoli cell maturation. These results suggest that germ cell differentiation in buffalo testis xenograft can be completed by altering the recipient gonadal status.

Germ cell differentiation in cryopreserved, immature, Indian spotted mouse deer (Moschiola indica) testes xenografted onto mice

“…Tissues that were cryopreserved in 10% DMSO showed significant increase in tubular and lumen diameter 24 weeks after xenografting compared with the tubular and lumen diameter of donor tissue. This is suggestive of germ cell development and change in Sertoli cell morphology in frozen-thawed xenografts, as reported previously [23].…”

“…Immunolocalization of PCNA has been used for studying cell proliferation in developing testes [23]. In testis tissues that were grafted after cryopreservation in 10% DMSO, PCNA-stained germ cell number was similar to that in donor tissues.…”

“…Grafts were recovered, weighed, fixed in Davidson's fixative, and processed as previously described [23]. Although the recipient mice were intact, seminal vesicle weight from all recipient mice was assessed to rule out changes in testosterone level as a result of negative feedback control because of grafted testicular tissues.…”

Regeneration of Leydig cells in ectopically autografted adult mouse testes

“…Seminal vesicles from all autografted mice were weighed for assessment of the bioactive circulating testosterone level (Honaramooz et al 2002, Reddy et al 2012. Blood was collected from autografted mice at the time when being killed by cardiac puncture, and serum was subsequently collected by centrifugation.…”

“…Successful generation of sperm from xenografts of immature testes from mice, hamsters, monkeys , bulls (Oatley et al 2005), pigs, goats (Honaramooz et al 2002), cats (Snedaker et al 2004), buffaloes (Reddy et al 2012) and mouse hosts has already been reported. Previous studies have shown that xenografted testis tissue from sexually mature donors is less successful than that from sexually immature donors (Arregui et al 2008).…”