Effect of passive immunization with buffalo follicular fluid antisera on ovarian activity in guinea pigs

Ovarian activity and follicular populations were studied in guinea pigs (Cavia porcellus) following administration of antisera against buffalo follicular fluid (buFF). Antibodies were raised in rabbits and the titre tested by immunodiffusion assay. Fourteen guinea pigs cycling normally were randomized into two groups. Animals in Group I (n=8) were treated (i.p.) with 0.5 ml antisera and in Group II (control, n=6) with the same volume of normal rabbit serum at 12 h intervals on the 10th and 11th day of their oestrous cycle. They were sacrificed 24 h after onset of estrus when ovulation points were counted and ovaries processed for microscopical examination. Treatment with buFF-antisera increased ovulation rate (3.6 vs. 2.0; p<0.01) but had no significant effect on the total number of follicles. However, the treatment reduced the percentages of atretic follicles in all size classes. These results indicated that the administration of a buFF-antisera produced in the rabbits increased ovulation rate in guinea pigs by reducing the incidence of atresia.     

Plasma follicle stimulating hormone,ovulation rate and fertility in Merino ewes treated with bovine follicular fluid

Charcoal-treated bovine follicular fluid (bFF) given as four 5-ml subcutaneous injections to 13 Merino-Border Leicester ewes around the time of natural luteolysis suppressed (P<0.01) plasma levels of follicle stimulating hormone (FSH) [from 1.08 ± 0.05 to 0.41 ± 0.03, mean ± s.e.m. of log_e (ng+ 1) /mlplasma]. This was followed (P < 0.01) by hypersecretion or a rebound of FSH (to 1.46 ± 0.11) lasting 32 h in 10 of the treated ewes, and then by a further fall (to 0.73 ± 0.03, P < 0.05) before the surge (1.21 ± 0.07, P < 0.05) associated with the preovulatory surge of luteinizing hormone (LH).Plasma FSH at 56–72 h before the LH surge (i.e., at the time of the FSH rebound) was correlated with the subsequent ovulation rate (n=13, r= + 0.73, P < 0.01). Fewer ewes treated with four injections of 2 or 5 ml of bFF than control ewes (injected with bovine plasma) became pregnant (28 of 41 vs. 38 of 41, χ² = 4.05, P < 0.05), although plasma progesterone was similar at Day 11 in treated and control ewes. It is concluded that plasma FSH during such a rebound influences the subsequent ovulation rate in sheep.     

Use of bovine follicular fluid to increase ovulation rate or prevent ovulation in sheep

Romney ewes were injected intramuscularly once or twice daily for 3 days with 0, 0.1, 0.5, 1 or 5 ml of bovine follicular fluid (bFF) treated with dextran-coated charcoal, starting immediately after injection of cloprostenol to initiate luteolysis on Day 10 of the oestrous cycle. There was a dose-related suppression of plasma concentrations of FSH, but not LH, during the treatment period. On stopping the bFF treatment, plasma FSH concentrations 'rebounded' to levels up to 3-fold higher than pretreatment values. The mean time to the onset of oestrus was also increased in a dose-related manner by up to 11 days. The mean ovulation rates of ewes receiving 1.0 ml bFF twice daily (1.9 +/- 0.2 ovulations/ewe, mean +/- s.e.m. for N = 34) or 5.0 ml once daily (2.0 +/- 0.2 ovulations/ewe, N = 25) were significantly higher than that of control ewes (1.4 +/- 0.1 ovulations/ewe, N = 35). Comparison of the ovaries of ewes treated with bFF for 24 or 48 h with the ovaries of control ewes revealed no differences in the number or size distribution of antral follicles. However, the large follicles (greater than or equal to 5 mm diam.) of bFF-treated ewes had lower concentrations of oestradiol-17 beta in follicular fluid, contained fewer granulosa cells and the granulosa cells had a reduced capacity to aromatize testosterone to oestradiol-17 beta and produce cyclic AMP when challenged with FSH or LH. No significant effects of bFF treatment were observed in small (1-2.5 mm diam.) or medium (3-4.5 mm diam.) sized follicles. Ewes receiving 5 ml bFF once daily for 27 days, from the onset of luteolysis, were rendered infertile during this treatment period. Oestrus was not observed and ovulation did not occur. Median concentrations of plasma FSH fell to 20% of pretreatment values within 2 days. Thereafter they gradually rose over the next 8 days to reach 60% of pretreatment values where they remained for the rest of the 27-day treatment period. Median concentrations of plasma LH increased during the treatment period to levels up to 6-fold higher than pretreatment values. When bFF treatment was stopped, plasma concentrations of FSH and LH quickly returned to control levels, and oestrus was observed within 2 weeks. The ewes were mated at this first oestrus and each subsequently delivered a single lamb.     

Effect of dominant follicle removal before superstimulation on follicular growth, ovulation and embryo production in Holstein cows

This study was to investigate whether removing the dominant follicle 48 h before superstimulation influences follicular growth, ovulation and embryo production in Holstein cows. After synchronization, ovaries were scanned to assess the presence of a dominant follicle by ultrasonography with a real-time linear scanning ultrasound system on Days 4, 6 and 8 of the estrus cycle (Day 0 = day of estrus). Twenty-six Holstein cows with a dominant follicle were divided into 2 groups in which the dominant follicle was either removed (DFR group, n=13) by ultrasound-guided follicular aspiration or left intact (control group, n=13) on Day 8 of the estrus cycle. Superovulation treatment was initiated on Day 10. All donors were superovulated with injections of porcine FSH (Folltropin) twice daily with constant doses (total: 400 mg) over 4 d. On the 6th and 7th injections of Folltropin, 30 mg and 15 mg of PGF2alpha (Lutalyse) were given. Donors were inseminated twice at 12 h and 24 h after the onset of estrus. Embryos were recovered on Day 6 or 7 after AI. During superstimulation, the number of follicles 2 to 5 mm (small), 6 to 9 mm (medium) and > or = 10 mm (large) was determined by ultrasonography on a daily basis. At embryo recovery, the number of corpora lutea (CL) was also determined by ultrasonography and blood samples were collected for analysis of progesterone concentration. Follicular growth during superstimulation was earlier in the DFR group than in the control group. The number of medium and large follicles was greater (P < 0.01) in the DFR group than in the control group on Days 1 to 2 and Days 3 to 4 of superstimulation, respectively. The numbers of CL (9.6+/-1.1 vs 6.1+/-0.9) and progesterone concentration (30.9+/-5.4 vs 18.6+/-3.5 ng/mL) were greater (P < 0.05) in the DFR group than in the control group, respectively. The numbers of total ova (7.7+/-1.3 vs 3.9+/-1.0) and transferable embryos (4.6+/-0.9 vs 2.3+/-0.8) were also greater (P < 0.05) in the DFR group than in the control group, respectively. It is concluded that the removal of the dominant follicle 48 h before superstimulation promoted follicular growth, and increased ovulation and embryo production in Holstein cows.     

Increase in ovulation rate after treatment of ewes with bovine follicular fluid in the luteal phase of the oestrous cycle

Administration of charcoal-treated bovine follicular fluid to Damline ewes twice daily (i.v.) from Days 1 to 11 of the luteal phase (Day 0 = oestrus) resulted in a delay in the onset of oestrous behaviour and a significant increase in ovulation rate following cloprostenol-induced luteolysis on Day 12. During follicular fluid treatment plasma levels of FSH in samples withdrawn just before injection of follicular fluid at 09:00 h (i.e. 16 h after previous injection of follicular fluid) were initially suppressed, but by Day 8 of treatment had returned to those of controls. However, the injection of follicular fluid at 09:00 h on Day 8 still caused a significant suppression of FSH as measured during a 6-h sampling period. Basal LH levels were higher throughout treatment due to a significant increase in amplitude and frequency of pulsatile secretion. After cloprostenol-induced luteal regression at the end of treatment on Day 12, plasma levels of FSH increased 4-fold over those of controls and remained higher until the preovulatory LH surge. While LH concentrations were initially higher relative to those of controls, there was no significant difference in the amount of LH released immediately before or during the preovulatory surge. These results suggest that the increase in ovulation rate observed during treatment with bovine follicular fluid is associated with the change in the pattern of gonadotrophin secretion in the luteal and follicular phases of the cycle.     

Effect of dominant follicle persistence on follicular fluid oestradiol and inhibin and on oocyte maturation in heifers

The aim of the present study was to characterize in detail the cytoplasmic and nuclear morphology of cattle oocytes recovered from follicles that are dominant for more than 9 days (with low fertility after ovulation), and to relate morphological changes to intrafollicular markers of follicle health. Beef heifers received prostaglandin F2 alpha and a synthetic progestagen (3 mg Norgestomet) for 2 or 10 days on the first day of dominance of the second dominant follicle (DF2) of the oestrous cycle, to give a 4 day (n = 19; N2) or 12 day (n = 21; N10) duration of dominance of the dominant follicle at ovariectomy 18 h after implant removal and before the predicted gonadotrophin surge. Ultrasound scanning determined emergence of a new wave of follicles in five N10 heifers the day before (n = 1) or day of ovariectomy (n = 4) (N10-NonDom). Dominant follicles from the remaining N10 heifers (N10-Dom) were larger (P < 0.05) on the day of ovariectomy (17.8 +/- 0.6 mm) than those from N2 heifers (13.6 +/- 0.4 mm). The oestradiol:progesterone ratio of follicular fluid from N10-Dom heifers was reduced (21.7 +/- 3.1 versus 34.1 +/- 4.4; P < 0.05), while inhibin A (as measured by immunoradiometric assay) was increased (12.7 +/- 1.0 versus 9.0 +/- 0.7 micrograms ml-1; P < 0.05) compared with N2 heifers. Eleven of twelve N2 oocytes demonstrated nuclear activation without germinal vesicle breakdown, while seven of eight N10-Dom oocytes had undergone germinal vesicle breakdown and had progressed to metaphase I (6/8) or II (1/8). In contrast to N2 oocytes, N10-Dom oocytes showed a larger perivitelline space containing more cumulus cell process endings, vacuoles, irregular vesicles, and more mitochrondia and lipid droplets throughout the ooplasm, yet the degree of cumulus cell expansion and atresia was similar. Thus, final oocyte maturation leading to metaphase I is initiated in most dominant follicles with a dominance period of > 9 days before the gonadotrophin surge and is associated with a reduction in dominant follicle health. However, ovulatory ability is maintained and will lead to the ovulation of aged oocytes, markedly reducing subsequent pregnancy rates.     

Effect of immunizing prepuberal lambs of low and high ovulation rate genotypes with inhibin partially purified from bovine follicular fluid

Active immunization of prepuberal lambs with a partially purified inhibin preparation, isolated from bovine follicular fluid, increased the ovulation rate. In ewe lambs of a low fecundity breed (Suffolk x Galway), the ovulation rate rose from 1.15 to 1.95 (P<0.05) compared with that of the controls. An ovulation rate of 3.38 was recorded for immunized ewe lambs of a high fecundity breed (Finn x Dorset Horn), while the rate for mature ewes from the same flock was 2.29. Immunization did not affect the time of onset of puberty or estrous cycle length. Following immunization, antibodies were produced that bound to a pure preparation of 68kDa bovine inhibin. This report demonstrates the production of antibody to a 68kDa preparation of inhibin following active immunization of sheep using a partially purified preparation. It was concluded that the increased ovulation rate was due to the production of antibodies to inhibin, which may have reduced its negative feedback effect of FSH secretion.     

Effect of 30 kDa and above buffalo follicular fluid protein treatment and immunization on ovarian functions in goats (Capra hircus)

Information on the use of buffalo follicular fluid (buFF) in modulation of ovarian functions in farm animals is scanty compared to other species. This is an attempt to investigate the effect of direct administration and active immunization of 30 kDa and above buFF proteins on ovarian functions in goats. Treatment of goats (n = 6) with steroid free 30 kDa and above buFF protein fraction during late-luteal phase for 4 days (days 12 or 13 to days 15 or 16) of the natural cycle, delayed the onset of estrus by 24 h compared to control although the mean duration of estrus was unaffected. A 71% increase (P = 0.06) in mean ovulation number was also observed following treatment. However, the population of large (> or =5 mm diameter) follicle was not affected. The ovarian activity calculated as total of ovulation and large follicles increased (1.6 times) significantly (P = 0.02) in treated animals. Active immunization of goats (n = 5) against these proteins did not affect the onset and duration of estrus. Similarly, the ovulation rate, number of large follicles and the ovarian activity did not differ significantly between immunized and control groups. The study revealed that 30 kDa and above buffalo follicular fluid contains some factor(s) that cause delay in the onset of estrus in goats and increase the ovulation rate. Active immunization against these proteins in goat did not show any effect either on onset, duration of estrus or ovulation rate and large follicle population. Detailed study on these buffalo follicular fluid proteins may help to use them further for modulation of ovarian function in farm animals.     

Effect of location and stage of development of dominant follicle on ovulation and embryo survival rate in alpacas

This study was designed to determine the effect of location of the preovulatory dominant follicle and stage of ovarian follicle development on ovulation rate and embryo survival in alpacas. In Experiment 1, mature lactating alpacas were randomly assigned to one of two groups according to the location of the dominant follicle detected by ultrasonography: (a) Right ovary (RO, n=96) or (b) Left ovary (LO, n=108). All females were mated once by an intact adult male. Ovulation rate, CL diameter and embryo survival rate (heartbeat) were assessed by ultrasonography on Days 2 (Day 0=mating), 8 and 30, respectively. Ovulation rate (96.5 and 96.3% for RO and LO group, respectively), corpus luteum (CL) diameter (10.2 and 10.6 mm for RO and LO group, respectively) and pregnancy rate (60.2 and 56.7% for RO and LO group, respectively) did not differ among groups. In Experiment 2, lactating alpacas (n=116) were submitted to ultrasonic-guided follicle ablation to synchronize follicular wave emergence. Afterwards, daily ultrasonography examinations were performed and females were randomly assigned to the following groups according to the growth phase and diameter of the dominant follicle: (a) early growing (5-6 mm, n=27), (b) growing (7-12 mm, n=30); (c) static (7-12 mm, n=30), or (d) regressing phase (12-7 mm, n=29). All alpacas were mated with a proven intact male, except five alpacas from early growing group that rejected the male. Females were examined by ultrasonography on Day 2 (ovulation rate), Day 8 (CL diameter), and Days 15, 20, 25, 30 and 35 (embryo survival by the presence of embryo proper and heartbeat). No differences were detected in ovulation rate among groups (96%, 97%, 100%, and 97%) or in CL size (10.3, 11.7, 11.1, and 11.1 mm, for early growing, growing, early static and regressing, respectively). Although, embryo survival rate at Day 35 after mating was numerically greatest in growing (65.5%), intermediate in early growing (52.4%) and static (53.3%), and least in regressing phase (42.9%), there were no differences among groups. Results suggest that neither location nor stage of development of the dominant follicle has an influence on ovulation and embryo survival rate in alpacas.     

Effect of GnRH treatment during the anovulatory season on multiple ovulation rate and on follicular development during the ensuing pregnancy in mares

Seasonally anovulatory mares were injected, i.m., twice daily with a GnRH analogue (GnRH-A), and hCG was given when the largest follicle reached 35 mm in diameter. In Exp. 1, treatment was initiated on 23 December when the largest follicle per mare was less than or equal to 17 mm. An ovulatory response (ovulation within 21 days) occurred in 17 of 30 (57%) GnRH-A-treated mares on a mean of 15.8 days. The shortest interval to ovulation in control mares (N = 10) was 57 days. The diameter of the largest follicle first increased significantly 6 days after start of treatment. In Exp. 2, treatment was begun on 15 January and mares were categorized according to the largest follicle at start of treatment. The proportion of mares ovulating within 21 days increased significantly according to initial diameter of largest follicle (less than or equal to 15 mm, 9/25 mares ovulated; 15-19 mm, 13/21; 20-24 mm, 20/24; greater than 25 mm, 3/3). The multiple ovulation rate was greater (P less than 0.01) for treated mares (27/86 mares had multiple ovulations) than for control mares (2/35). Treated mares in which the largest follicle at start of treatment was greater than or equal to 25 mm had a higher (P less than 0.01) multiple ovulation rate (9/14) than did mares in which the largest follicle was less than 25 mm (18/72). The pregnancy rate for single ovulators was not different between control mares (26/30 pregnant mares) and treated mares (43/54).(ABSTRACT TRUNCATED AT 250 WORDS)     

Oocyte retrieval and histological studies of follicular population in buffalo ovaries

Ovaries (N = 250) from slaughtered buffaloes were collected to study follicular population and compare methods of oocyte retrieval. The number and size of surface follicles were recorded and grouped into different categories. Different sized follicles in relation to oocyte diameter were studied histologically. Yield of oocytes per ovary were less (P < 0.05) from ovaries bearing a corpus luteum (CL). Techniques used for oocyte recovery included slicing, follicle puncture and aspiration. The oocyte recovery rate was greatest (P < 0.05) using slicing. The average number of visible surface follicles was 5.20 ± 0.97 with mean numbers of 2.5, 1.2, 0.82 and 0.62 per ovary for follicles sized 4, 8, 12 and 12 mm respectively. Histological studies revealed large numbers of primordial follicles in prepubertal and atretic follicles in senile buffaloes. They also established a biphasic relationship of growth between oocyte diameter and follicular size.     

Effect of recombinant bovine somatotropin (bST) on follicular population and on in vitro buffalo embryo production

The objective of this study was to evaluate the effect of bovine somatotropin (bST) on ovarian follicular population in buffalo heifers and its influence on oocyte quality, recovery rates and in vitro embryo production. We tested the hypothesis that bST treatment in buffalo females submitted to an ovum pick-up (OPU) program would improve the number of follicles recruited, oocyte quality and in vitro embryo production. A total of 10 heifers were assigned into two treatment groups: group bST (n=5; receiving 500 mg of bST in regular intervals) and control group (n=5; without additional treatment). Both groups were subjected to OPU sessions twice a week (every 3 or 4 days), for a total of 10 sessions per female, although due to procedural problems, only the first five OPU sessions produced embryos. The number of follicles and the diameters were recorded at all OPU sessions. The harvested oocytes were counted and classified according to their quality as either A, B, C, D or E, with A and B considered good quality. Cleavage and blastocyst production rates were evaluated 2 and 7 days after in vitro fertilization, respectively. The bST treatment increased the total number of antral follicles (>3mm in diameter; 12.2 compared with 8.7; p<0.05) and of small antral follicles (<5mm; 9.1 compared with 6.5; p<0.05) per OPU session. The bST also tended to increase the number of oocytes recovered per session (5.2 compared with 4.1; p=0.07), and enhanced the percentage of good quality oocytes (48.8% compared with 40.6%; p=0.07). bST showed no effect on cleavage and blastocyst production rates (p>0.05). The significant effects of performing repeated OPU sessions were decreasing the follicular population (p<0.001) as well as the number of follicles aspirated (p<0.001), and oocytes recovered (p<0.02). In conclusion, bST treatment improves the follicular population, demonstrating its possible application in buffalo donors submitted to OPU programs.     

Effect of pregnant mare's serum gonadotropin on increased ovulation in guinea pigs with synchronized estrous cycle

An ability of Pregnant Mare's Serum Gonadotropin (PMSG) to induce superovulation was investigated in guinea pigs with synchronized estrous cycle caused by the treatment for 21 days of progesterone tubing. On day 6 later following the removal of progesterone treatment, every animal given saline injection had synchronously ovulated. When compared with saline control, a significant increase of ova ovulated was induced by an injection of PMSG 8 hours before the removal of progesterone tubing, but not by the other PMSG treatment schedule. Present study indicates that PMSG injection given at a fixed stage of synchronized estrous cycle induced superovulation in guinea pigs treated with long-term implantation of progesterone tubing.     

Effect of bovine follicular fluid administration during or after norgestomet treatment on the fate of the proestrus dominant follicle in heifers

The objective was to examine the influence of follicle stimulating hormone (FSH) on the maintenance and ovulation of the proestrus dominant follicle (DF) in cattle. This was investigated by subjecting a proestrus DF, maintained by a single norgestomet (N) implant, to bovine follicular fluid (BFF) injections during N treatment and immediately after its removal. Earlier, we demonstrated that with an insertion of a single N implant the proestrus DF could be maintained for 9 days without affecting its ovulatory capacity. Eighteen cycling Holstein heifers were treated with a N implant at proestrus. The day of implant insertion was designated day 1 of the implant period and the implant was retained for 9 days. Heifers (n = 6 per group) were randomly allocated to receive saline for 4 days from day 5 to day 8 of the implant period and for 4 days from the day of implant removal to day 3 after removal (CONTROL) or BFF from day 5 to day 8 of implant period (BFF-DURING) or BFF from the day of implant removal to day 3 after implant removal (BFF-AFTER). Injections (10 ml) were given i.v. twice daily and the ovaries monitored by ultrasonography daily, throughout and after the implant period. All CONTROL heifers maintained the DF during treatment and ovulated following implant withdrawal. In all BFF-DURING heifers, the BFF injections caused regression of the DF and its disappearance. In three of the BFF-AFTER heifers, BFF injections caused regression of the DF. In the remaining three BFF-AFTER heifers, the DF ovulated. Mean plasma FSH concentrations did not differ (P > 0.05) between the CONTROL and BFF-DURING heifers. However, the mean plasma FSH concentrations were lower in BFF-AFTER heifers compared with CONTROLS (P < 0.05). Mean plasma LH concentrations did not differ among treatment groups (P > 0.05). In summary, BFF treatment caused atresia of the proestrus DF when maintained by N and this was not associated with suppression of circulating FSH. Administration of BFF after implant removal resulted in an equal chance of ovulation or regression of DF. Regression was associated with suppression of FSH and LH.     

Delayed follicular development and ovulation following inhibition of FSH with equine follicular fluid in the mare

In two experiments, PGF(2alpha) was given to all mares on Day 10 (ovulation = Day 0). In experiment 1, mares received either whole follicular fluid or saline i.v. every 12 hours on Days 10 to 14. Experiment 2 was similar to experiment 1, except the follicular fluid was extracted with charcoal to remove steroids. Analysis of the FSH data for Days 10 to 21 indicated an effect of treatment (P<0.08) with whole follicular fluid, but not with charcoal-extracted follicular fluid. However, there was an effect of day (P<0.05) and an interaction (P<0.01) of treatment with day for both experiments. The interaction of treatment with day seemed primarily due to a marked post-treatment increase in FSH concentrations between Days 15 and 17 for mares treated with either whole follicular fluid or charcoal-extracted follicular fluid. Analysis of the diameter of the largest follicle for Days 10 to 18 indicated a main effect of treatment (P<0.05) and day (P<0.05) and an interaction (P<0.05) of treatment with day for both experiments. The interaction of treatment with day was attributable to the inhibition of follicular growth by Day 14 for mares treated with whole follicular fluid and by Day 15 for mares treated with charcoal-extracted follicular fluid. The length of the interovulatory interval was longer (P<0.05) in the treated group than in controls for both experiments. Results indicated that equine follicular fluid contained a proteinaceous substance that suppressed circulating concentration of FSH. The inhibited follicular growth and the delay in ovulation were attributed to the reduced concentrations of circulating FSH.     

Depression of follicle stimulating hormone in bulls injected with follicular fluid

Eight bulls were divided into two groups and injected with either charcoal-extracted steer blood serum or charcoal-extracted bovine follicular fluid (bFF). Ten-milliliter injections were given subcutaneous every 12 h for 4 wk. Jugular blood collected before, during and after the injection period was analyzed for follicle-stimulating hormone (FSH) and luteinizing hormone (LH) by radioimmunoassay. All bulls were exposed to restrained, estrual heifers for 15 min every 2 wk for 16 wk starting 4 wk before the first injection. The number of mounts and services by each bull was recorded. Semen was collected with an artificial vagina and evaluated on alternate weeks during the same period. The concentration of FSH in serum decreased (P < 0.05) by 12 h after the first injection and remained 61% lower than that of serum-injected bulls during the injection period. The concentration of FSH increased (P < 0.05) by 3 d after the last injection. Injections of bFF did not affect the concentration of LH in serum. Bovine follicular fluid injections significantly depressed FSH; however, libido, serving capacity, and semen characteristics were unchanged.     

Biochemical composition of ovine follicular fluid in relation to follicle size

The aim of this study was to biochemically characterize ovine follicular fluid and to relate possible changes in composition to follicular size. Ovaries were collected from adult and cycling non-pregnant slaughtered sheep (Ovis aries) during breeding season. A total of 104 pairs of ovaries were investigated and these data were then compared. Follicular fluid was aspirated from small (< 2 mm), medium (2-4 mm) and large (> 4 mm) nonatretic ovarian follicles. The follicular fluid was centrifuged at 4 degrees C and 5000 g for 30 min to remove any cells and stored at -80 degrees C prior to assay. Follicular fluid samples were analyzed for glucose, total protein, cholesterol, triglycerides, lactate, urea, creatinine, sodium, potassium, chloride, calcium, phosphorus, magnesium, acid phosphatase, alkaline phosphatase, and lactate dehydrogenase. Data were analyzed by the linear regression model. As follicles became larger, the concentrations of glucose and cholesterol significantly (P < 0.05) increased while those of triglycerides, lactate, alkaline phosphatase and lactate dehydrogenase significantly (P < 0.05) decreased.     

卵泡液中细胞外囊泡及其携带的microRNA对卵泡发育的作用

细胞外囊泡(Extracellular vesicles,EVs)是指细胞分泌的双层膜转运囊泡。EVs能从细胞中摄取大分子物质,并将其转移至受体细胞。在这些大分子物质中,研究最多的就是microRNA (miRNA)。miRNA是一种参与基因表达调控的非编码RNA,已证实在哺乳动物卵泡液EVs中有不同的非编码RNA存在,EVs携带miRNA可以作为自分泌和旁分泌的替代机制,影响卵泡发育。文中系统介绍了EVs的种类、特征和分离鉴定方法,重点综述了EVs及携带的miRNA对卵泡发育的作用,包括早期卵泡发育、卵母细胞成熟、卵泡优势化以及对颗粒细胞功能的影响。同时对卵泡液中EVs及其携带的miRNA的未来研究进行了展望,为卵泡液中EVs及携带的miRNA功能的研究及应用提供了思路和方向。     

The relation between patterns of ovarian follicle growth and ovulation rate in sheep

The number and growth rate of follicles within classes based on granulosa volume were determined for ovaries taken from groups of 4-5-year-old, fine-wool Merino ewes drawn at different times of the year from a single strain flock maintained at Armidale, N.S.W. The breeding season of the flock normally extends from February to October and the mean ovulation rate rises from about 0.5 in February to about 1.8-1.9 during April-May. Ewes sampled when they were anoestrous or had one (single-ovulatory) or two (twin-ovulatory) recent corpora lutea did not differ in respect to the mean total number of ovarian follicles, the mean number of follicles in individual classes, the time for follicles to complete their rapid growth stage, or the incidence of follicle atresia. However, the ovaries of twin-ovulatory ewes contained significantly more follicles in the two terminal classes within the rapid growth stage than did the ovaries of single-ovulatory or anoestrous ewes (2.2 v. 0.9 and 1.0). This difference was attributed to the differing numbers of follicles per day entering into the rapid growth stage (5.2, 4.5 and 3.7 respectively in twin-ovulatory, single-ovulatory and anoestrous ewes).