Sexual maturation of the Mongolian gerbil (Meriones unguiculatus): a histological, hormonal and spermatic evaluation

Abstract

This study determined the phases of sexual development of the male Mongolian gerbil (Meriones unguiculatus) based on an integrative analysis of testicular morphology, hormonal data and sperm parameters. Male gerbils were analysed at 1, 7, 14, 21, 28, 35, 42, 50, 60, 70, 90, 100 and 120 days of age. Body, testicular and epididymal weights increased up to Day 70, 60 and 90, respectively. The impuberal phase, characterised by the presence of gonocytes, extended until Day 14. The prepubertal period lasted until Day 42, when puberty was achieved and a drastic increase in serum testosterone levels, mature adult Leydig cells and elongated spermatids was observed. Gerbils at 60 days of age showed a remarkable number of spermatozoa in the testis, epididymidis caput/corpus and cauda, and at Day 70 the maximum daily sperm production was reached. However, the gerbil may be considered sexually mature only from Day 90 onward, when sperm reserves become stable. The total transit time of spermatozoa along the epididymis of sexually mature gerbils was 11 days, with 1 day in the caput/corpus and 10 days in the cauda. These data cover a lacuna regarding the reproductive parameters of this rodent and provide foundations for its use in testicular toxicology studies.

Pubertal exposure to ethinylestradiol promotes different effects on the morphology of the prostate of the male and female gerbil during aging

“…We utilized eight senile female gerbils and eight senile male gerbils ( Meriones unguiculatus , Muridae: Gerbillinae) to form the experimental groups. These females and males, upon completing 42 days of postnatal life, received by gavage 15 µg/kg/day of ethinylestradiol (EE, Formula: C 20 H 24 O 2, Form: solid) (17α‐ethinylestradiol; E4876 Sigma, St. Louis, MO) diluted in 100 µL of mineral oil Nujol® (CAS 8020‐83‐5; Sigma‐Aldrich, St Louis, MO) for 1 week during the puberty period (Pinto‐Fochi et al, ). This group was named the EE/PUB group.…”

Prenatal and pubertal exposure to 17α‐ethinylestradiol cause morphological changes in the prostate of old gerbils

“…The exposure to EE occurred from the 18th to 22nd day of gestation, during the prostatic morphogenesis period (Sanches et al, 2014). After this exposure, five male and five female pups housed separately, from birth through weaning (30 days) and received the same dosage of EE from the 42nd to 49th day, which corresponds to puberty in gerbils (Pinto‐Fochi et al, 2016). The control group no received treatment, being intact group.…”

Prepubertal chrysin exposure upregulates either AR in male ventral prostate or AR and ERα in Skene's paraurethral gland of pubertal and adult gerbils

“…The mating day was determined by the presence of spermatozoa in the vaginal smears; this day was considered as day zero, being the initial day of the gestational period [19]. After birth, pups (48 male and 48 female) were destined to form the following groups: Control group (C)animals received oral doses of the dilution vehicle (corn oil; 100 μL/ animal) from the 15th until 42nd day of postnatal life (impubertal or prepubertal phase according to Pinto-Fochi et al [20]; Chrysin group (Chr)animals received oral doses of chrysin (25 mg/kg/day; according to the dose used by Darwish et al [6]) from the 15th until the 42nd day of postnatal life; Testosterone group (T-positive control group)animals received subcutaneous injections of testosterone cypionate (1 mg/kg/week; Deposteron/EMS) from the 15th until the 42nd day of postnatal life. Male and female gerbils were euthanized at either 43 days (puberty onset) or 90 days (adult onset) of postnatal life.…”