Production of normal young following transfer of mouse embryos obtained by in vitro fertilization between cryopreserved gametes

Abstract

Summary. Development of the prepubertal interstitium of the right testes was characterized every 14 days from 10 to 122 days of age in intact boars (I) and boars hemicastrated (HC) at 10 days of age from two herds (Trial 1 and Trial 2). Comparisons were made between the remaining testis of Group-HC boars and one testis in Group-I boars. The relative mass (mass of component/body mass) of interstitium was 151% greater (P < 0·001) in Group-HC than Group-I boars by 52 days of age. The relative mass of interstitium was greater (P < 0·01) in Trial-1 than Trial-2 boars within each treatment from 80 to 122 days of age. The relative mass of interstitial space was 76% greater (P < 0·05) in Group-HC than in one testis of Group-I boars by 52 days of age and greater (P < 0·05) in Trial-1 than Trial-2 boars within each treatment from 80 to 122 days of age. The relative mass of Leydig cells was 254% greater (P < 0·0001) in Group-HC than Group-I boars by 52 days of age and remained greater (P < 0·05) in Group-HC than Group-I boars from 52 to 122 days of age. By 52 days of age the relative mass of Leydig cell nuclei and cytoplasm was 235% and 265% greater (P < 0·0001) in Group-HC than Group-I boars, respectively, and both remained greater (P < 0·05) in Group-HC than in Group-I boars until 122 days of age. The relative mass of small vessels was 86% greater (P < 0·01) in Group-HC than Group-I boars from 24 to 66 days of age and was similar in Group-I and Group-HC boars from 66 to 122 days of age. The relative mass of Leydig cells, nuclei and cytoplasm as well as small vessels was similar between trials of boars within each treatment. Neonatal hemicastration of boars at 10 days of age therefore resulted in an overcompensation in numbers of Leydig cells, measured as nuclear mass, whereas the increase in vascular development and interstitial space did not fully compensate the loss of testicular tissue. The cytoplasm to nuclear ratio reflected the steroid production of the Leydig cells which was related to pubertal tubular development rather than treatment.