Chronic intermittent immobilization of male rats throughout sexual development: a stress protocol

In order to investigate whether prolonged stress interferes with the onset of sexual behavior at puberty and with fertility at adulthood, prepubertal male Wistar rats (40 days of age) were immobilized 6 h a day for 15 days (up to early puberty) or for 60 days (until sexual maturity). Pubertal stressed rats showed a two-fold increase in the latency for the first mount (probably due to repeated aversive experience in which a change of environment was always followed by immobilization) and a 2.5-fold increase in the frequency of thrusting (indicative of enhanced sexual performance). The apparently stimulatory effect of prolonged stress on the onset of sexual behavior is discussed in terms of increased testosterone level and interference with the complex interchanges between the neurotransmitters/neuropeptides involved in the central control of male sexual activity. Adult stressed animals were mated with normal females, which became pregnant but exhibited a more than two-fold increase in both preimplantation and post-implantation loss, probably due to a smaller rate of fertilization and/or fertilization with damaged spermatozoa.

Section: Discussionsupporting

confidence: 58%

Section: Discussionmentioning

confidence: 96%

Sexual behavior and fertility of male rats submitted to prolonged immobilization-induced stress

Almeida

Kempinas

Carvalho

2000

“…We showed that forced swimming stress caused a significant decrease in the number of spermatids in seminiferous tubules. This result supports literature data showing the inhibition of spermatogenesis in response to various stressors (1,3,10). Spermatogenesis in the rat is divided into 14 stages or cell associations (16) and the complete sequence of these stages constitutes one cycle of the seminiferous epithelium, which lasts 48 to 53 days in the rat (16).…”

supporting

confidence: 78%

“…Spermatogenesis in the rat is divided into 14 stages or cell associations (16) and the complete sequence of these stages constitutes one cycle of the seminiferous epithelium, which lasts 48 to 53 days in the rat (16). Although the response of plasma testosterone concentration to stressful stimuli was not measured in the present study, literature data strongly support the hypothesis that the decrease in circulating testosterone levels of stressed males can be responsible for depressing spermatogenesis (10,13,15). In addition, stress may activate the hypothalamicpituitary-adrenal axis (4) and the roles of corticotropin-releasing hormone, adrenocorticotropin (ACTH) and the adrenal glucocorticoids in the regulation of gonadotropinreleasing hormone (GnRH) pulse generator activity have also been studied extensively The forced swimming-stressed rats were submitted to 3-min daily forced swimming for 15 days.…”

supporting

confidence: 61%

Fertility of male adult rats submitted to forced swimming stress

Mingoti

Pereira

Monteiro

2003

We investigated whether stress interferes with fertility during adulthood. Male Wistar rats (weighing 220 g in the beginning of the experiment) were forced to swim for 3 min in water at 32ºC daily for 15 days. Stress was assessed by the hot-plate test after the last stressing session. To assess fertility, control and stressed males (N = 15 per group) were mated with sexually mature normal females. Males were sacrificed after copulation. Stress caused by forced swimming was demonstrated by a significant increase in the latency of the pain response in the hot-plate test (14.6 ± 1.25 s for control males vs 26.0 ± 1.53 s for stressed males, P = 0.0004). No changes were observed in body weight, testicular weight, seminal vesicle weight, ventral prostate weight or gross histological features of the testes of stressed males. Similarly, no changes were observed in fertility rate, measured by counting live fetuses in the uterus of normal females mated with control and stressed males; no dead or incompletely developed fetuses were observed in the uterus of either group. In contrast, there was a statistically significant decrease in spermatid production demonstrated by histometric evaluation (154.96 ± 5.41 vs 127.02 ± 3.95 spermatids per tubular section for control and stressed rats, respectively, P = 0.001). These data demonstrate that 15 days of forced swimming stress applied to adult male rats did not impair fertility, but significantly decreased spermatid production. This suggests that the effect of stress on fertility should not be assessed before at least the time required for one cycle of spermatogenesis.

“…A diversity of aversive stimuli applied to animal models on a short-or long-term basis have been used to investigate the response of the HPA and/or gonadal axis to stress (14,15). Stress-related hormones are known to modulate male reproductive functions by interfering with the hypothalamic pituitary-gonadal axis.…”

Section: Introductionmentioning

confidence: 99%

Different stress modalities result in distinct steroid hormone responses by male rats

Andersen

Bignotto

Machado

et al. 2004

132

Since both paradoxical sleep deprivation (PSD) and stress alter male reproductive function, the purpose of the present study was to examine the influence of PSD and other stressors (restraint, electrical footshock, cold and forced swimming, N = 10 per group) on steroid hormones in adult Wistar male rats. Rats were submitted to chronic stress for four days. The stressors (footshock, cold and forced swimming) were applied twice a day, for periods of 1 h at 9:00 and 16:00 h. Restrained animals were maintained in plastic cylinders for 22 h/day whereas PSD was continuous. Hormone determination was measured by chemiluminescent enzyme immunoassay (testosterone), competitive immunoassay (progesterone) and by radioimmunoassay (corticosterone, estradiol, estrone). The findings indicate that PSD (13.7 ng/ dl), footshock (31.7 ng/dl) and cold (35.2 ng/dl) led to lower testosterone levels compared to the swimming (370.4 ng/dl) and control (371.4 ng/dl) groups. However, progesterone levels were elevated in the footshock (4.5 ng/ml) and PSD (5.4 ng/ml) groups compared to control (1.6 ng/ml), swimming (1.1 ng/ml), cold (2.3 ng/ml), and restrained (1.2 ng/ml) animals. Estrone and estradiol levels were reduced in the PSD, footshock and restraint groups compared to the control, swimming and cold groups. A significant increase in corticosterone levels was found only in the PSD (299.8 ng/ml) and footshock (169.6 ng/ml) groups. These changes may be thought to be the full steroidal response to stress of significant intensity. Thus, the data suggest that different stress modalities result in distinct steroid hormone responses, with PSD and footshock being the most similar.