Premature Ovarian Insufficiency (POI) Induced by Dynamic Intensity Modulated Radiation Therapy via P13K-AKT-FOXO3a in Rat Models.

This study is aimed to investigate the mechanisms of radiation-induced mouse models of premature ovarian insufficiency (POI). Wistar female rats were grouped into the control, 3.2 Gy, 4.0 Gy, and 4.8 Gy groups. Overall ovarian functions were assessed with the H&E staining and ELISA. Proinflammatory cytokine secretion was analyzed ELISA, and the reactive oxygen species (ROS) levels were analyzed with immunohistochemistry. Protein expressions were analyzed by Western blot analysis. The 4.0 Gy and 4.8 Gy groups had significantly lower ovarian weight coefficients than the control and 3.2 Gy groups (after only one irradiation therapy). The 3.2 Gy radiation group induced periodic disturbance and hormone change at 4 weeks after radiation. In the 4.0 Gy and 4.8 Gy groups, the preantral follicles and antral follicles were decreased, while Atresia follicles were increased. E2 was decreased, while FSH and LH secretions were increased. The ovaries in the 4.0 Gy group were not completely atrophied, and some preantral follicles remained. Ovarian atrophy and follicular Atresia were found in the 4.8 Gy group. Inflammatory and oxidative markers were upregulated. PI3K and AKT were downregulated in the 4.0 Gy and 4.8 Gy groups, while FOXO3a was upregulated. Ovarian injuries may lead to oxidative damages and inflammatory injuries, downregulate the expression of P13k and Akt, upregulate the expression of FOXO3a, and lead to follicular atresia in the ovary.

Regulation of the MAPK signaling pathway by miR-421-5p in rats under light pollution.

The present study aimed to explore the difference in the expression profiles of ovarian microRNA sequences in rats in a light pollution environment and rats in a normal light environment. Rats in the control group were exposed to 12­h light/dark cycles, while rats in the model group were continuously exposed to 24­h light. The ovaries were extracted from the two groups of rats, and Illumina HiSeq 2500 high­throughput sequencing technology was used to detect the differences in microRNA (miRNA) expression among the two groups. Fluorescence quantitative reverse transcription­polymerase chain reaction was used to verify the differential expression of miRNA. The present study was designed to experimentally validate the interaction between miR­421­5p and mitogen­activated protein kinase (MAPK) 7 by using the dual­luciferase reporter system, and to explore the expression of proteins in the MAPK signaling pathway with a lentiviral vector­mediated small hairpin RNA interference against microRNA­421­5p. The expression of 45 miRNAs was significantly different. In total, 13 miRNAs were upregulated, of which 5 miRNA sequences were known and 8 were predicted. Furthermore, 32 miRNAs were downregulated, of which 11 miRNA sequences were known and 21 were predicted. The results of the luciferase reporter assay confirmed the targeting association between miR­421­5p and MAPK7. The expression levels of MAPK and genes in its downstream signaling pathways, including c­Fos, CREB and c­Myc, were downregulated when miR­421­5p was overexpressed and upregulated when miR­421­5p was silenced. The differential expression of miRNAs may serve an important role in the development of the ovary in a light pollution environment. miR­421­5p may regulate ovarian growth and development by targeting the MAPK signaling pathway in light polluted rat ovaries.

Effects of far-infrared ray on reproduction, growth, behaviour and some physiological parameters in mice.

The effects of chronic exposure to far-infrared ray (FIR) on reproduction, growth, behaviour, survival time and some related parameters were examined in SHN mice. The reproductive parameters differed slightly between the females on the normal racks and those on the FIR racks, which emitted FIR from the ceiling. The age and body weight on the day of vaginal opening was lower in the experimental mice born and maintained on the FIR rack than in the control on the normal rack. In both sexes, the levels of urinary components in the experimental group was significantly higher than the control at 6-7 months of age. Spontaneous motor activity of females during the light and dark phases were higher and lower, respectively, in the experimental group than the control. The survival rate was significantly higher in the experimental group than the control. These findings suggest that FIR has 'normalization effects' on the organisms.

[The sex and corticosteroid hormones of rats selected for estrous-cycle reaction to constant illumination]. / Polovye i kortikosteroidnye gormony krys, selektsionirovannykh po reaktsii éstral'nogo tsikla na postoiannoe osveshchenie.

Two substrains of rats selected for the high (ESTH) and low (ESTL) ability to develop permanent oestrus under constant illumination were produced. The concentration of estradiol, testosterone in blood and 11-OCS in blood and adrenals was studied in rats of the 29 th generation under normal day (14L : 10D) and constant illumination (CL). The concentration of estradiol in blood of control rats in proestrus was 61.6 +/- 4.1 pg/ml and did not differ from substrain ESTH (59.6 +/- 4.5 pg/ml) and ESTL (58.8 +/- 4.8 pg/ml); in oestrus, the minimal concentration of estradiol was noted in control-(46.5 +/- 3.1 pg/ml), maximal one-in rats of substrain ESTL (63.3 +/- 6.2 pg/ml), in ESTH-55.8 +/- 1.7 pg/ml. The maintenance of rats in condition of CL brought about the tendency to decrease the level of estradiol in blood of rats selected in proestrus and to increase it in oestrus in comparison to control. The level of testosterone in blood of control rats in proestrus-oestrus changed in parallel to concentration of estradiol. The concentration of testosterone in blood of selected rats was higher in proestrus-oestrus as compared to control. In condition of CL, the testosterone level in proestrus did not differ from control, in oestrus it was higher than in control. The level of 11-OCS in adrenals of selected substrain was higher than in control as well in condition of 14L : 10D as in CL. The exception was substrain ESTH-in proestrus the concentration of 11-OCS in condition of CL was lower than in control. CL drastically changed direction of cyclic shifts in level of 11-OCS from higher value in proestrus under condition of 14L : 10D to low one in condition of CL. The fluctuation of 11-OCS level in blood in groups of experimental rats usually was parallel to that in adrenals.

Effect of light regimen under various ambient temperatures on sow and litter performance.

Primiparous Large White females were exposed to one of two light regimens characterized by an increase (from 12 to 16 h/d, LONG treatment) or a decrease (from 12 to 8 h/d, SHORT treatment) in photoperiod during gestation. Two successive replicates were conducted, and farrowings occurred in January and July. During the last month of gestation, during lactation and after weaning, ambient temperatures varied between 18 and 25 degrees C and between 25 and 38 degrees C for the first and second replicates, respectively. Weaning occurred at 3 wk postpartum. Percentage of sows in estrus within 10 d after weaning was higher (P < .05) in the SHORT than in the LONG group for both replicates and when farrowing occurred in January compared with July for both photoperiod groups (SHORT-January: 92%, LONG-January: 53%, SHORT-July: 32%, LONG-July: 14%). Loss of live weight in sows during lactation was higher in July than in January and higher in the SHORT than in the LONG photoperiod (P < .05). Live weight of pigs at birth was higher in July than in January, whereas growth rate of pigs until weaning was higher in January (P < .05). Temperature may have a greater influence on sow and litter performance than photoperiod.

Actions of acetyl-L-carnitine on the hypothalamo-pituitary-gonadal system in female rats.

Acetyl-L-carnitine (ALC) is known to affect several aspects of neuronal activity. To evaluate the neuroendocrine actions of this compound, several endocrinological parameters were followed in ALC-treated and control animals during recovery from dark-induced anestrus. In treated animals, serum luteinizing hormone (LH) and prolactin levels were higher than those of controls during the proestrous and estrous phases of the cycle, and serum estradiol levels were higher during estrus. No significant changes were observed in serum levels of follicle-stimulating hormone and progesterone. Uterine weight was increased in ALC-treated rats during proestrus and estrus, but not in diestrus. The basal release of gonadotropin-releasing hormone (GnRH) from perifused hypothalamic slices of ALC-treated animals was elevated at proestrus and diestrus, and GnRH release elicited by high K+ was higher during all three phases of the cycle. The basal release of LH from perifused pituitaries of treated animals was elevated in diestrus, and the LH response to GnRH was higher in estrus and diestrus I. Depolarization with K+ caused increased LH secretion during proestrus and estrus in treated animals. In contrast to these effects of ALC treatment in vivo, no direct effects of ALC were observed during short- or long-term treatment of cultured pituitary cells. These results indicate that ALC treatment influences hypothalamo-pituitary function in a cycle stage-dependent manner, and increases the secretory activity of gonadotrophs and lactotrophs. Since no effects of ALC on basal and agonist-induced secretory responses of gonadotrophs were observed in vitro, it is probable that its effects on gonadotropin release are related to enhancement of GnRH neuronal function in the hypothalamus.

The effect of an extended artificial photoperiod and gonadotrophin-releasing hormone infusions in inducing fertile oestrus in anoestrous mares.

The occurrence of fertile oestrus early in the breeding season is of paramount importance to the Thoroughbred industry to facilitate early conception. This paper compares 2 techniques for inducing fertile oestrus in anoestrous mares using either an extended photoperiod alone or together with gonadotrophin-releasing hormone (GnRH) infusions. Eleven mares were placed under conditions of 16 h light and 8 h darkness and 5 of these were implanted with osmotic minipumps delivering approximately 100 ng GnRH/kg/h for 28 days (treated mares). The treated mares ovulated 27.7 days earlier than and conceived 32 days earlier than the 6 mares not given GnRH. GnRH-induced ovulations were followed by a competent luteal phase. The combination of GnRH pumps implanted 2 weeks before commencement of service together with extended photoperiod from July 1 has promise in assisting the stud breeder to improve reproductive efficiency on commercial stud farms.

Proposal of an experimental model for the study of polycystic ovaries.

In view of the correlation of the circadian system with the estrous cycle in the rat, some investigators have proposed the induction of polycystic ovaries by exposing rats to continuous light. However, there is divergence with respect to time of exposure and light intensity. In the present paper we propose a simple and efficient experimental model for the study of polycystic ovarian physiopathology in rats. Twenty female Wistar rats weighing 200-220 g were initially submitted to a 14-h light/10-h dark cycle. Of the animals with regular estrous cycles, 9 were exposed to continuous light (600 lux) for 74 days (group 1) and 6 remained under the initial lighting conditions. A daily vaginal smear was used as indirect evidence for the changes in the estrous cycle. Plasma gonadotropin measurement and histological ovarian analysis showed that 90% of the animals in group 1 developed cystic follicles with the absence of the corpus luteum, despite the lack of reduction in ovarian weight commonly observed under 24-h lighting. This observation may be explained by the reduced time of stress to which the animals were submitted, since polycystic ovarian development occurred within less than 75 days of continuous exposure to 600-lux light, a time relatively shorter than commonly reported in the literature.

Proposal of an experimental model for the study of polycystic ovaries

In view of the correlation of the circadian system with the estrous cycle in the rat, some investigators have proposed the induction of polycystic ovaries by exposing rats to continuous light. However, there is divergence with respect to time of exposure and light intensity. in the present paper we propose a simple and efficient experimental model for the study of polycystic ovarian physiopathology in rats. Twenty female Wistar rats weighing 200-220 g were initially submitted to a 14-h light/10-h dark cycle. of the animals with regular estrous cycles, 9 were exposed to continuous light (600 lux) for 74 days (group 1) and 6 remained under the initial lighting conditions. A daily vaginal smear was used as indirect evidence for the changes in the estrous cycle. Plasma gonadotropin measurement and histological ovarian analysis showed that 90% of the animals in group 1 developed cystic follicles with the absence of the corpus luteum, despite the lack of reduction in ovarian weight commonly observed under 24-h lghting. This observation may be explained by the reduced time of stress to which the animals were submitted, since polycystic ovarian development occurred within less than 75 days of continuous exposure to 600-lux light, a time relatively shorter than commonly reported in the literature

Increased FSH levels precede short photoperiod-induced anestrus in intact and unilaterally ovariectomized LSH/SsLak hamsters.

Anestrus brought about after 2-4 weeks of short photoperiod (SP) exposure in LSH/SsLak hamsters is preceded by impaired follicular development. Since the latter is critically dependent on adequate FSH levels, this study tested the hypothesis that SP might alter baseline or compensatory FSH levels prior to the onset of anestrus. Regularly cycling females in 141:10 (LP) were transferred to SP (8L:16D). Between 0800 and 0900 h on days 20 through 24 of SP exposure, half of the animals in diestrus II were unilaterally ovariectomized (UO), and the remaining animals were sham-operated (Sham-UO). Seven hours after surgery, blood samples were taken via cardiac puncture. All animals were killed the following morning at 0900 h. Uterine weights were significantly reduced in SP-exposed hamsters, yet the compensatory increase in FSH following unilateral ovariectomy was not affected; a tendency for higher levels was noted. On proestrus, serum and pituitary FSH levels of SP-exposed Sham-UO animals were significantly elevated over similarly treated LP-exposed hamsters. Interestingly in animals with severe follicular impairment, the highest FSH levels correlated with the lowest uterine weights. The data suggest that SP exposure does not impair compensatory FSH release or the ability of the ovaries to respond to UO. SP-induced elevations in FSH levels may result from reduced follicular secretion and reduced inhibin and/or estrogen levels.

Effect of continuous illumination on secretion of pregnane compounds by the rat ovary.

Differences in the secretion of pregnane compounds from rats with follicular polycystic ovaries under constant light and with normal preovulatory ovaries under light-dark conditions were compared. The injection of LH greatly increased the secretion of progesterone. 5 alpha-pregnane-3,20-dione and 3 alpha-hydroxy-5 alpha-pregnan-20-one, in both types of ovaries, but the response of the two progesterone metabolites in the polycystic ovaries was low, suggesting low 5 alpha-reductase activity.

Effects of multiple injections of luteinizing hormone on secretion of pregnane compounds from polycystic ovaries of rats exposed to constant light.

Differences in the secretion of pregnane compounds by ovaries with cystic follicles of rats exposed to constant light (light-induced oestrous rats) and by ovaries with normal follicles of early pro-oestrous rats were studied. Some rats were injected iv with 2 micrograms of LH to stimulate the secretion of steroids 30 min before their blood was sampled. The injection greatly increased the secretion of progesterone by both kinds of ovaries. The secretion of 5 alpha-pregnane-3,20-dione and 3 alpha-hydroxy-5 alpha-pregnan-20-one also increased in normal rats, but not in the polycystic ovaries of light-induced oestrous rats, which suggested that the 5 alpha-reductase activity was low. The pre-ovulatory LH surge is absent in light-induced oestrous rats, so a classic approach was taken to circumvent the probable deficit in the cyclic release of LH; we gave multiple injections of 10 micrograms of LH. Five such injections were given at intervals of 4 days, and ovarian venous blood was collected 4 days after the last injection. Cystic follicles in the ovaries of rats disappeared when the injections of LH were given every 4 days. The production of 5 alpha-pregnane-3,20-dione and 3 alpha-hydroxy-5 alpha-pregnan-20-one from the ovaries of such rats was significantly higher (P less than 0.01) than in controls given multiple injections of saline. These results suggest that the low 5 alpha-reductase activity in polycystic ovaries of light-induced oestrous rats may be due to the absence of an LH surge from the pituitary gland.

Early short photoperiod effects in female LSH/SsLak Syrian hamsters.

Previous experiments showed that LSH/SsLak female hamsters cease ovarian cyclicity after 2-4 weeks of short photoperiod (SP) treatment. This study was designed to reveal early hormonal and histological changes on day 1 of the estrous cycle (estrus) in SP-treated animals and changes brought about by the SP-induced acyclic condition. Groups of 8-10 animals were killed on day 1 after 0, 4, 8, 12, and 16 days of SP treatment; sera and pituitaries were saved for hormone determinations, and ovaries were prepared for histological analysis. Intraatrial cannulae were inserted into anovulatory animals, and blood samples were withdrawn on the first and second postoperative days; the animals were killed on the third postoperative day. PRL levels were significantly reduced in cycling animals after 16 days of SP exposure and diminished further in acyclic animals. Pituitary PRL did not change in cycling animals, although it was highly depressed in SP-treated acyclic animals. The estrous FSH surge, serum LH levels, and pituitary gonadotropin contents were not affected by SP in cycling animals; in anovulatory animals, pituitary gonadotropin contents were significantly increased, and daily afternoon gonadotropin surges were observed. Uterine weights were reduced in cycling animals and underwent a further reduction after cyclicity ceased. Ovarian analysis revealed that all cycling animals had the same number of recruited follicles, yet significantly fewer corpora lutea and an apparent increase in atretic antral follicles were observed after 16 days of SP exposure. These results suggest that SP-induced cessation of estrous cyclicity occurs abruptly. SP does not alter the secondary FSH surge, but might adversely affect maintenance of follicular growth and depress serum PRL levels.

Influence of continuous illumination on estrous cycle of rats: time course of changes in levels of gonadotropins and ovarian steroids until occurrence of persistent estrus.

Plasma concentrations of LH, FSH, 17 beta-estradiol, estrone and progesterone were determined chronologically by radioimmunoassays in two groups of adult female rats exposed to continuous illumination (LL). Group 1 rats showing vaginal estrous cycles were sacrificed at 3- to 6-hour intervals during late proestrus through early estrus of the first 5 cycles after exposure to LL. Group 2 animals which displayed persistent vaginal estrus in an early period of exposure to LL were killed on the 2nd, 3rd, 4th, 5th and 7th days of vaginal estrus. In Group 1 rats, surges of the hormones, except estrone, took place in all the 5 cycles. The occurrence of peak hormone levels in each cycle was invariably delayed after transfer of animals to LL. According to regression analyses, the lengths of secretion cycles of LH, FSH, 17 beta-estradiol and progesterone in rats under LL were 100.89, 100.46, 101.14 and 101.06 h, respectively. Elevation of 17 beta-estradiol levels was observed prior to the LH surge, and peaks of progesterone and FSH occurred following it. However, the secretion patterns of these hormones appear to be disrupted with length of exposure to LL. In group 2 rats, the mean concentration of LH during persistent estrus was approximately similar to that on the morning of the days of proestrus of the 4-day cycles of rats placed under an alternating 12-hour light-dark regimen (LD), whereas the mean FSH concentration was continuously low. While the concentrations of 17 beta-estradiol and estrone in persistent-estrous rats were elevated, progesterone levels remained low.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of 6-hydroxydopamine and 5,6-Dihydroxytryptophan on the luliberin and luteinizing hormone levels in female rats under constant illumination]. / Vliianie 6-oksidofamina i 5,6-oksitriptofana na uroven' liuliberina i liuteiniziruiushchego gormona u samok krys pri postoiannom osveshchenii.

Administration of 5,6-oxytryptophan to female rats' 3rd cerebral ventricle, as opposed to 6-oxydopamine, prevents the decrease in the luteinizing hormone contents in the blood occurring under constant illumination. Administration of 6-oxydopamine against the background of desmethylimipramine caused a significant increase of the luliberine contents in the anterior hypothalamus while preserving its normal level in the medio-basal portion.