Prenatal exposure to diaethylstilbestrol in the rat inhibits transabdominal testicular descent with involvement of the INSL3/LGR8 system and HOXA10.
BACKGROUND
Prenatal exposure to diaethylstilbestrol (DES) has been found to lead to intra-abdominal cryptorchidism, but the mechanism is still not completely clear. This study investigated the roles of the INSL3/LGR8 system and HOXA10 in DES-induced intra-abdominal cryptorchidism (DIIAC). The effect of DES on steroidogenic factor-1 (SF-1), that has been reported to control transcription of insulin-like factor 3 (INSL3), was also investigated.


METHODS
Fifty pregnant female SD rats at embryonic day 13.5 (E13.5) were randomly assigned to five groups that received a subcutaneous injections of dimethyl sulfoxide (control), 2.5 mg/kg, 5 mg/kg, 10 mg/kg, or 20 mg/kg of DES. Male offspring were sacrificed at E19.5, and fetal mortality and the degree of transabdominal testicular ascent (DTA) were determined under a stereomicroscope. The mRNA expression of INSL3 and SF-1 in the testis and leucine rich repeat-containing G protein-coupled receptors 8 (LGR8) and homeobox-A10 (HOXA10) in the gubernaculum were determined by RT-PCR. The expression of INSL3 protein was determined by Western blotting.


RESULTS
Higher fetal mortality and DTA were induced by DES in a dose-dependent manner (P < 0.01). Compared with the control group, the expression of INSL3 and SF-1 mRNA were down-regulated in a dose-dependent manner (P < 0.01), as was INSL3 protein; HOXA10 in the 2.5 mg/kg group and LGR8 mRNA in the 2.5 mg/kg and 5 mg/kg groups were not significantly different (P > 0.05); HOXA10 mRNA in groups C, D, and E decreased significantly and LGR8 mRNA levels in groups D and E increased significantly (P < 0.05, P < 0.01, respectively).


CONCLUSIONS
DES can inhibit transabdominal testicular descent in a dose-dependent manner via down-regulating the expression of INSL3, which is induced by down-regulating the expression of SF-1. HOXA10 may not be involved in DES induced intra-abdominal cryptorchidism at 2.5 mg/kg, but is involved at 5, 10 and 20 mg/kg. LGR8 may not be responsible for DES-induced transabdominal testicular maldescent.
Zhang
Lin
L
Department of Urology, Zhongnan Hospital, Wuhan University, Wuhan, Hubei 430071, China.
Zheng
Xin-min
XM
Hubert
Jacques
J
Zheng
Hang
H
Yang
Zhi-wei
ZW
Li
Shi-wen
SW
D000818:Animals; D015153:Blotting, Western; D003456:Cryptorchidism / Q000139:chemically induced* / Q000378:metabolism*; D004054:Diethylstilbestrol / Q000633:toxicity*; D004968:Estrogens, Non-Steroidal / Q000633:toxicity*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D000080905:Homeobox A10 Proteins; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology*; D007279:Injections, Subcutaneous; D007328:Insulin / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008297:Male; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054339:Steroidogenic Factor 1 / Q000235:genetics / Q000502:physiology
D004968:Estrogens, Non-Steroidal; C534680:HOXA10 protein, rat; D000080905:Homeobox A10 Proteins; D018398:Homeodomain Proteins; D007328:Insulin; C084797:Leydig insulin-like protein; D011506:Proteins; D043562:Receptors, G-Protein-Coupled; C511608:Rxfp2 protein, rat; D054339:Steroidogenic Factor 1; D004054:Diethylstilbestrol