Duration of spermatogenesis and daily sperm production in the rodent Proechimys guyannensis.
The spiny rat (Proechimys guyannensis) is a neotropical rodent that is used in biomedical research, particularly research related to chronic resistance to epilepsy and infectious diseases. To our knowledge, there are few reports concerning the reproductive biology of this species. Therefore, besides providing basic biometric and morphometric data, in the present study we investigated testis function and spermatogenesis in adult spiny rats. The mean testis weight and gonadosomatic index obtained were 1.63 ± 0.2 g and 1.15 ± 0.1% respectively. Based on the development of the acrosomic system, 12 stages of the seminiferous epithelium cycle were characterized. Stages VI and VII presented the highest frequencies (~17-19%), whilst stages II to V showed the lowest frequencies (~2-4%). The most advanced germ cell types labelled at 1 h or 20 days after BrdU injections were respectively preleptotene/leptotene spermatocytes at stage VII and elongated spermatids at stage III. The mean duration of one cycle was 7.5 ± 0.01 days and the entire spermatogenic process lasted 33.7 ± 0.06 days (~4.5 cycles). The seminiferous tubules (ST) occupied ~96 ± 1% of the testis parenchyma, whereas Leydig cells comprised only 1.5 ± 0.4%. The number of Sertoli cells (SC) per testis gram and the SC efficiency (spermatids/SC) were respectively 78 × 106 ± 11 × 106 and 7.9 ± 1. The daily sperm production per testis gram (spermatogenic efficiency; daily sperm production (DSP)/g/testis) was 78 × 106 ± 8 × 106. To our knowledge, this spermatogenic efficiency is among the highest found for mammals investigated to date and is probably related to the very short duration of spermatogenesis and the very high ST percentage and SC number obtained for this species.
Laboratory of Cellular Biology,Department of Morphology,Federal University of Minas Gerais,Belo Horizonte,Minas Gerais 31270-901,Brazil.
Nathália L M
NL
Lara
Department of Biosystems Engineering,Federal University of São João Del-Rei,São João Del-Rei,Minas Gerais 36307-352,Brazil.
Ivan C
IC
Santos
Laboratory of Cellular Biology,Department of Morphology,Federal University of Minas Gerais,Belo Horizonte,Minas Gerais 31270-901,Brazil.
Guilherme M J
GM
Costa
Laboratory of Cellular Biology,Department of Morphology,Federal University of Minas Gerais,Belo Horizonte,Minas Gerais 31270-901,Brazil.
Dirceu A
DA
Cordeiro-Junior
Department of Biosystems Engineering,Federal University of São João Del-Rei,São João Del-Rei,Minas Gerais 36307-352,Brazil.
Antônio C G
AC
Almeida
Department of Biosystems Engineering,Federal University of São João Del-Rei,São João Del-Rei,Minas Gerais 36307-352,Brazil.
Ana P
AP
Madureira
Department of Veterinary Medicine,Federal University of Espirito Santo,Vitoria,Espirito Santo 29075-910,Brazil.
Marcos S
MS
Zanini
Laboratory of Cellular Biology,Department of Morphology,Federal University of Minas Gerais,Belo Horizonte,Minas Gerais 31270-901,Brazil.
Luiz R
LR
França
D000818:Animals; D007985:Leydig Cells / Q000166:cytology; D008297:Male; D009929:Organ Size; D012377:Rodentia / Q000502:physiology*; D012670:Seminiferous Epithelium / Q000502:physiology; D012708:Sertoli Cells / Q000166:cytology; D013076:Sperm Count; D013091:Spermatogenesis / Q000502:physiology*; D013094:Spermatozoa / Q000166:cytology / Q000502:physiology; D013737:Testis / Q000033:anatomy & histology / Q000166:cytology*
P. guyannensis; Sertoli cell efficiency; Sperm production; Spermatogenesis; Spiny rat; Testis