[Effects of prepubertal continuous exposure to dibutyl phthalate on testicular development in rats].
OBJECTIVE
To investigate the effects of prepubertal continuous exposure to dibutyl phthalate (DBP) on the testis development in SD rats.


METHODS
Twenty-one-day-old weanling prepubertal male SD rats were randomly divided into a control (n = 24) and an experiment group (n = 54), gavaged daily with corn oil vehicle or corn oil + DBP at the repeated dose of 0 mg/(kg x d) (control), 50 mg/(kg x d) (low-dose), 200 mg/(kg x d) (medium-dose) and 600 mg/(kg x d) (high-dose) for 14, 21 and 28 days, and then sacrificed by decapitation on PND35, PND42 and PND49. The body weight gain, the testis weight and volume and the weight of accessory sex organs were measured, the serum testosterone level assayed by chemoluminescence technique, the testis tissues stained by H&E and observed under the light microscope for morphological alteration, the mean diameter of the seminiferous tubules determined and testicular biopsy scores obtained.


RESULTS
Disordered arrangement of spermatogenic cells was found in some seminiferous tubules on PND35 in the low-dose group, but testis development and spermatogenesis were normal on PND42 and PND49. In the medium-dose group, disordered arrangement and decreased number of spermatogenic cells were observed on PND35 and PND42, but without testicular atrophy, and various grades of spermatogenic cells and sperm were seen on PND49. High-dose DBP slowed down the body weight gain, decreased serum T levels and induced degeneration of seminiferous tubules, arrest of spermatogenic epithelium development and necrosis of spermatogenic cells. The pubertal rats (PND49) showed testicular atrophy, azoospermia and delayed development of accessory sex organs.


CONCLUSIONS
Prepubertal continuous exposure to DBP induces damages to testicular development and spermatogenesis in a dose-dependent manner, and those induced by high-dose DBP cannot be recuperated in the phase of prepubertal development, while the slight adverse effects on the testis induced by low- and medium-dose DBP could be completely or partly reversible before PND49.
Long
Ting
T
Department of Physiology, Shantou University Medical College, Shantou, Guangdong 515031, China.
Tian
Er-Po
EP
Qin
Da-Nian
DN
Wang
Yong
Y
D000818:Animals; D003993:Dibutyl Phthalate / Q000633:toxicity*; D004781:Environmental Exposure; D006128:Growth / Q000187:drug effects; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013737:Testis / Q000187:drug effects* / Q000254:growth & development
D003993:Dibutyl Phthalate