Adverse effects of a clinically relevant dose of hydroxyurea used for the treatment of sickle cell disease on male fertility endpoints.

Two experiments were conducted to determine: 1) whether the adult male transgenic sickle cell mouse (Tg58 x Tg98; TSCM), exhibits the patterns of reproductive endpoints (hypogonadism) characteristic of men with sickle cell disease (SCD) and 2) whether hydroxyurea (HU) exacerbates this condition. In Experiment 1, blood samples were collected from adult age-matched TSCM and ICR mice (ICRM) (N = 10/group) for plasma testosterone measurements. Subsequently, mice were sacrificed, testes excised and weighed and stored spermatozoa recovered for the determination of sperm density, progressive motility and percentage of spermatozoa with normal morphology. In experiment 2, adult male TSCM were orally treated with 25 mg HU/kg body weight/day for 28 or 56 days. Control mice received the vehicle for HU (saline) as described above. At the end of the treatment periods, blood samples were collected for quantification of circulating testosterone. Subsequently, mice were sacrificed, testes and epididymides were recovered and weighed and one testis per mouse was subjected to histopathology. Stored spermatozoa were recovered for the determination of indices of sperm quality mentioned in Experiment 1. Testis weight, stored sperm density, progressive motility, percentage of spermatozoa with normal morphology and plasma testosterone concentrations of TSCM were significantly lower by 40, 65, 40, 69 and 66%, respectively than those of ICRM. These data indicate that adult TSCM used in this study suffered from hypogonadism, characteristically observed among adult male SCD patients. In Experiment 2, HU treatment significantly decreased testis weight on day 28, (0.09 +/- 0.004 g) that was further decreased on day 56 (0.06 +/- 0.003 g; treatment x time interaction) compared with controls (day 28, 0.15 +/- 0.01 g; day 56, 2, 0.16 +/- 0.01 g). Concomitant with a 52% shrinkage (P<0.001) in area of testes in 56 days of HU treatment, testes from HU-treated TSCM exhibited significant atrophic degeneration in the seminiferous tubules compared with controls. Furthermore, treated TSCM had only Sertoli cells and cell debris remaining in most of the seminiferous tubules in comparison with controls. Leydig cell prominence and hyperplasia were more evident (P<0.05) in the steroidogenic compartments of testes of HU-treated TSCM compared with controls. However, plasma testosterone concentrations were reduced by HU treatment (P<0.05; treatment x time interaction) compared with controls on the two time periods studied. Epididymides from HU-treated TSCM sustained a 25% shrinkage (P<0.05), along with 69 (P<0.005) and 95% reduction (P<0.005), in stored sperm density and sperm progressive motility (treatment x time interaction P<0.05), respectively on day 56 of treatment compared with controls. These data demonstrate that TSCM used in this study exhibited SCD-induced hypogonadism, thus authenticating their use for studying the effect of HU on male reproductive endpoints observed in SCD patients. Secondarily, our data show that HU treatment exacerbated the already SCD-induced hypogonadism to gonadal failure.

Effects of benzo(a)pyrene on intra-testicular function in F-344 rats.

The objective of this study was to evaluate the reproductive risk associated with exposure of adult male Fisher-344 (F-344) rats to inhaled benzo(a)pyrene (BaP), a ubiquitous environmental toxicant present in cigarette smoke, automobile exhaust fumes and industrial emissions. Rats were assigned randomly to a treatment or control group. Treatment consisted of exposure of rats via nose-only inhalation to 75 microg BaP/m3, 4 hours daily for 60 days, while control animals were unexposed (UNC). Blood samples were collected immediately on day 60 of exposures (time 0) and subsequently at 24, 48, and 72 hours, to assess the effect of exposures to BaP on plasma testosterone and luteinizing hormone (LH) concentrations. Mean testis weight, total weight of tubules and total tubular length per paired testes were reduced 33% (P < 0.025), 27% (P < 0.01) and 39%, respectively in exposed rats (P < 0.01) compared with UNC rats. The number of homogenization -resistant spermatids was significantly reduced in BaP-exposed versus UNC rats. Plasma testosterone and intra-testicular testosterone (ITT) concentrations were significantly decreased by BaP compared with those of UNC rats. The decreases in circulating plasma testosterone were accompanied by concomitant increases in plasma LH concentrations in BaP-exposed versus control rats (P < 0.05). These data suggest that 60 days exposure to inhaled BaP contribute to reduced testicular endocrine and spermatogenic functions in exposed rats.