Sexual behaviour, sperm quantity and quality after short‐term streptozotocin‐induced hyperglycaemia in rats

Abstract

Studies of diabetes mellitus in the streptozotocin rat model suggest that sexual dysfunctions may result from diabetes-induced alterations of the neuroendocrine-reproductive tract axis. Our investigation was performed to better define the effects of short-term hyperglycaemia on rat epididymal sperm quantity, quality and transit time, using both natural mating and artificial in utero insemination protocols. Male rats were made diabetic with streptozotocin (sc, 40 mg/kg), whereas controls received vehicle. Sexual behaviour was tested after 15 days and sperm fertilizing ability was checked 22 days after the injection through natural mating and artificial in utero insemination. Other parameters such as daily sperm production, testosterone levels, as well as sperm morphology and motility were also investigated. Fifty per cent of the diabetic animals showed no copulatory behaviour during tests and the number of animals reaching ejaculation was smaller in the diabetic group when compared with the control group (33% vs. 83%). Diabetes resulted in decreased body and reproductive organ weights, as well as diminished sperm counts in the testis and epididymis, that were associated with diminution of plasmatic testosterone levels. After natural mating, there was a decrease in the fertility in the diabetic adult male rats (25.5%) compared with control animals (81.5%). However, distal cauda epididymal sperm from diabetic rats displayed normal fertilization ability (91.5%) using in utero insemination. There were no effects of hyperglycaemia on sperm transit time in the epididymis and on spermatogenesis. Our results indicate that diabetes mellitus produces reproductive dysfunction, but does not compromise sperm fertilizing ability in the cauda epididymis in this experimental model.

Germ cell abnormalities in streptozotocin induced diabetic mice do not correlate with blood glucose level

“…Although, the serum testosterone level declined significantly at the end of 36 days in STZ treated group, subsequent estimation on 72 day did not show any difference between control and diabetic groups. The review of earlier studies on the effect of hyperglycemia on plasma testosterone level has demonstrated conflicting results [16][17][18][19] possibly due to differences in study models and diabetes induction methods. With the decline in testosterone level at 36 days interval, we speculated an aberrant spermatogenesis in diabetic animals.…”

Evidence of oxidative stress and mitochondrial dysfunctions in the testis of prepubertal diabetic rats

“…8 Epidemiological evidences emphasize that oxidative stress plays an important role in the etiology of male infertility. 9 Our recent findings in STZ-diabetic adult rodent models have shown the occurrence of oxidative stress in the testis during acute phase and its progression.…”

Effects of experimental diabetes on testis proliferations and apoptosis in rats

“…Streptozotocin induced diabetes in male rats resulted atrophy of sex organ, changes in histoarchitecture of ventral prostate, diminution in sperm count (Sing et al, 2005), along with low levels in plasma gonadotrophins (Seethalakshmi et al, 1987) and testosterone (Sanguinetti et al, 1985). The copulatory behavior of diabetic rat has been collapsed along with low fertility in induced normal mating (Scarano et al, 2006). In human, diabetes is associated with erectile dysfunction (Takahashi et al, 1997) along with loss of libido and abnormal morphology of sperm, low plasma levels of gonadotrophins and testosterone (Dinulvic et al, 1990).…”