Date post: | 09-Jun-2015 |
Category: |
Education |
Upload: | jack-britt |
View: | 421 times |
Download: | 0 times |
BrittBrittAAPBAAPB20052005
Folliculogenesis – Factors Which Folliculogenesis – Factors Which Affect Oocyte Competence.Affect Oocyte Competence.
Jack H Britt
University of Tennessee
Getting the Most Out of Embryo TransferGetting the Most Out of Embryo Transfer
AABP Preconference Seminar 14 -- September 21, 2005 -- Salt Lake CityAABP Preconference Seminar 14 -- September 21, 2005 -- Salt Lake City
BrittBrittAAPBAAPB20052005
Confused about follicular development?Confused about follicular development?
BrittBrittAAPBAAPB20052005
Take Home MessagesTake Home Messages
Jack H Britt, University of TennesseeJack H Britt, University of Tennessee
Oocytes and follicles are formed during fetal development – but many Oocytes and follicles are formed during fetal development – but many degenerate before puberty – degenerate before puberty – most oocytes are lost earlymost oocytes are lost early..
Among cattle, follicle populations differ among animals but are Among cattle, follicle populations differ among animals but are repeatable within animals over lifetime – repeatable within animals over lifetime – more follicles = more oocytesmore follicles = more oocytes..
Number of growing follicles is directly related to the size of the resting Number of growing follicles is directly related to the size of the resting pool of follicles -- pool of follicles -- larger pool = more oocyteslarger pool = more oocytes..
Number of FSH-responsive follicles within an individual is highly Number of FSH-responsive follicles within an individual is highly repeatable – repeatable – responsive heifers = responsive cowsresponsive heifers = responsive cows..
Folliculogenesis takes months and quality of follicles and oocytes is Folliculogenesis takes months and quality of follicles and oocytes is affected by environmental conditions that exist during this period – affected by environmental conditions that exist during this period – follicle environment affects oocyte qualityfollicle environment affects oocyte quality..
BrittBrittAAPBAAPB20052005
Atretic
Preantral Follicles
Ovarian Microscopic and Ovarian Microscopic and Macroscopic StructuresMacroscopic Structures
BrittBrittAAPBAAPB20052005
Follicle Development and ActivationFollicle Development and Activation
Take Home MessageTake Home MessageOocytes and follicles are formed during fetal development – but many Oocytes and follicles are formed during fetal development – but many
degenerate before puberty – degenerate before puberty – most oocytes are lost earlymost oocytes are lost early..
BrittBrittAAPBAAPB20052005
Follicle and Oocyte Populations Follicle and Oocyte Populations in the Bovine Ovary in the Bovine Ovary
Cushman, DeSouza, Hedgpeth & Britt. 1999. Biol. Reprod. 60: 349-354 Cushman, DeSouza, Hedgpeth & Britt. 1999. Biol. Reprod. 60: 349-354
Follicle PopulationsFollicle Populations
0° - Primordial0° - Primordial
1° - Primary1° - Primary
2° - Secondary2° - Secondary
(about 140,000 at birth)(about 140,000 at birth)
0°
2°
1°
0°
1°
2°
1°
Primordial to PrimaryPrimordial to Primary
• Granulosa cells become Granulosa cells become cuboidalcuboidal
• Oocyte growth occursOocyte growth occurs
Primary to SecondaryPrimary to Secondary
• Granulosa cell proliferationGranulosa cell proliferation
• Multiple LayersMultiple Layers
• Zona PellucidaZona Pellucida
• Theca cell differentiationTheca cell differentiation
BrittBrittAAPBAAPB20052005
0
2
4
6
8
10
12
0
2
4
6
8
10
12
A. Primordial Follicles
a
bb
b b
a aaa
a
B. Primary Follicles
a
b
b bb
a a a
a
a
in vitro in ovo
Day 10 Day 7 Day 4 Day 2 Day 0
Nu
mb
er o
f fo
llicl
es p
er s
ecti
on
(±
SE
M)
Bovine Follicles Activate SpontaneouslyIn Vitro, but not In Ovo
Cushman et al. 2002. Hum Reprod 17:48; Gigli et al. 2005 Mol. Reprod. Develop.71:480Cushman et al. 2002. Hum Reprod 17:48; Gigli et al. 2005 Mol. Reprod. Develop.71:480
Procedures:Pieces of bovine ovarieswere cultured in vitro ortransplanted to fertilized chicken eggchorio-allantois membrane (in ovo).
Therefore:Activation is inhibited in tissue supplied with blood-- suggesting a blood borneinhibitor of gonadal origin
BrittBrittAAPBAAPB20052005
Duration of FolliculogenesisDuration of Folliculogenesis in the Bovine in the Bovine
Primordial
PrimordialPrimordial
40 days40 days10 days10 days10 days10 days??
80 to 100 days
FactorsFactors
Steroids Steroids &&
Growth Growth FactorsFactors
Growth Growth FSH & LHFSH & LH
Growth Growth FactorsFactors
FSHFSHGrowth Growth
FactorsFactors
FSHFSH
GraafianGraafianAntralAntralPreantralPreantralPrimaryPrimary
Britt, J. H. 1992. The Bovine Practitioner Proceedings 24: 39-43 Britt, J. H. 1992. The Bovine Practitioner Proceedings 24: 39-43
BrittBrittAAPBAAPB20052005
Follicle Numbers are RepeatableFollicle Numbers are Repeatable
Take Home MessageTake Home MessageAmong cattle, follicle populations differ among animals but are Among cattle, follicle populations differ among animals but are
repeatable within animals over lifetime – repeatable within animals over lifetime – more follicles = more oocytesmore follicles = more oocytes
BrittBrittAAPBAAPB20052005
Number of Follicles is Repeatable Number of Follicles is Repeatable Across Waves and CyclesAcross Waves and Cycles
Used with permission: Used with permission: Burns et al. 2005. BOR 73: 54-62Burns et al. 2005. BOR 73: 54-62
• Ovaries ultrasounded 2X DailyOvaries ultrasounded 2X Daily
• Cows (heifers and lactating or Cows (heifers and lactating or nonlactating cows, n=30) were nonlactating cows, n=30) were ranked for low (ranked for low (≤15), ≤15), intermediate (16-20), high (21-intermediate (16-20), high (21-25) or very high (>25) follicles 25) or very high (>25) follicles per wave.per wave.
• Note: Note: Repeatability of number of Repeatability of number of follicles (bars) per wavefollicles (bars) per waver=.95; 98 waves; 30 animalsr=.95; 98 waves; 30 animals
BrittBrittAAPBAAPB20052005
ComparisonComparison Correlation coefficientCorrelation coefficient
Season: Spring, Summer, FallSeason: Spring, Summer, Fall .86 to .95.86 to .95
Waves per cycles: two or threeWaves per cycles: two or three .93 to .95.93 to .95
Lactation: lactating or dryLactation: lactating or dry .93 to .94.93 to .94
Ultrasound technicianUltrasound technician .86 to .95.86 to .95
Age: Heifers or Cows Age: Heifers or Cows (see footnote)(see footnote) .92 to .96.92 to .96
OverallOverall .95.95
Repeatability of Number of Repeatability of Number of Follicles Follicles ≥ 3 mm in Holsteins≥ 3 mm in Holsteins
Burns et al. 2005. Biol. Reprod. 73: 54-62Burns et al. 2005. Biol. Reprod. 73: 54-62
No. follicles in same animals: As heifers, 21.2±1 vs As cows, 16.4±1
BrittBrittAAPBAAPB20052005
Follicle Pool Size Dictates Follicle Pool Size Dictates Populations Developing Populations Developing
Take Home MessageTake Home MessageNumber of growing follicles is directly related to the size of the resting Number of growing follicles is directly related to the size of the resting
pool of follicles -- pool of follicles -- larger pool = more oocyteslarger pool = more oocytes..
BrittBrittAAPBAAPB20052005
How about the relationship between theHow about the relationship between thenumber of follicles and ovulation rate?number of follicles and ovulation rate?
Ovulatory response in the Ovulatory response in the remainingremaining ovary was ovary was compared with the number of follicles in the compared with the number of follicles in the
contralateralcontralateral ovary removed before superovulation. ovary removed before superovulation.
Twenty-eight non-lactating Holstein and Jersey Cows
Unilateral ovariectomy - Day 8 of cycle Ipsilateral to CL
Exogenous gonadotropin - Day 9 of cycle FSH-P (28 mg) for 4 days Lutalyse (25 mg) twice on third day Remaining ovary collected on Day 8-12 of subsequent cycle to
quantify CL
Cushman, DeSouza, Hedgpeth & Britt. 1999. Biol. Reprod. 60: 349-354 Cushman, DeSouza, Hedgpeth & Britt. 1999. Biol. Reprod. 60: 349-354
BrittBrittAAPBAAPB20052005
CL Primordial Primary Secondary Tertiary
<5 77.4a 64.8 4.1 1.6a
5-14 178.2b 137.3 9.1 3.8b
>14 173.7b 95.7 9.1 3.8b
SEM 22.4 22.1 1.7 0.6
a,bP < 0.05 within a column
MicroscopicMicroscopic Follicles in the Bovine Ovary Follicles in the Bovine Ovary in Cows with Differing Responses to FSHin Cows with Differing Responses to FSH
Cushman, DeSouza, Hedgpeth & Britt. 1999. Biol. Reprod. 60: 349-354 Cushman, DeSouza, Hedgpeth & Britt. 1999. Biol. Reprod. 60: 349-354
BrittBrittAAPBAAPB20052005
CL
Total
Small
(<3 mm)
Medium
(3-7 mm)
Large
(>7mm)
<5 6.1a 2.4a 2.5a 1.3
5-14 22.4b 11.6b 9.3b 1.6
>14 21.7b 8.3b 11.1b 2.3
SEM 3.1 1.9 2.4 0.7
a,bP 0.06 within a column
MacroscopicMacroscopic Follicles in the Bovine Ovary Follicles in the Bovine Ovary in Cows with Differing Responses to FSHin Cows with Differing Responses to FSH
Cushman, DeSouza, Hedgpeth & Britt. 1999. Biol. Reprod. 60: 349-354 Cushman, DeSouza, Hedgpeth & Britt. 1999. Biol. Reprod. 60: 349-354
BrittBrittAAPBAAPB20052005
Ultrasound Test to Predict Ultrasound Test to Predict Superstimulatory Response in CattleSuperstimulatory Response in Cattle
Singh et al. Theriogenology 2004. 62:227-243.Singh et al. Theriogenology 2004. 62:227-243.
121 cows121 cows
Synchronized 1Synchronized 1stst wave (E and P to synchronize) wave (E and P to synchronize)
Ultrasound to estimate number of follicles Ultrasound to estimate number of follicles ≥≥2 mm2 mm
Synchronized 2Synchronized 2ndnd wave in high (n=16) and low (n=20) end cows wave in high (n=16) and low (n=20) end cows
FSH 2X daily for 3 daysFSH 2X daily for 3 days
Number of follicles after FSHNumber of follicles after FSH
5-7 mm: High end = 16.85-7 mm: High end = 16.8±2.2 vs Low end = 8.1±0.9±2.2 vs Low end = 8.1±0.9
≥ ≥ 8 mm: High end = 22.7±4.1 vs Low end = 9.7±1.68 mm: High end = 22.7±4.1 vs Low end = 9.7±1.6
Best predictor of superstimulatory response was Best predictor of superstimulatory response was number of follicles ≥2 mm at wave emergence.number of follicles ≥2 mm at wave emergence.
BrittBrittAAPBAAPB20052005
Follicle Numbers are Repeatable Follicle Numbers are Repeatable Within IndividualsWithin Individuals
Take Home MessageTake Home MessageNumber of FSH-responsive follicles within an individual is highly Number of FSH-responsive follicles within an individual is highly
repeatable – repeatable – responsive heifers = responsive cowsresponsive heifers = responsive cows..
BrittBrittAAPBAAPB20052005
0 4 8 12 16
1
3
5
7
9
Tw
in P
air
Average Number of Oocytes Per Session
Twin 2Twin 1
Characteristics of responses among Characteristics of responses among monozygotic twins to OPUmonozygotic twins to OPU
Machado et al. Theriogenology 2005. pre-release Machado et al. Theriogenology 2005. pre-release
9 pair of twins, OPU at 3-4 day intervals, 195 OPU sessions (10 or 11 per donor)
Only this pair differed
BrittBrittAAPBAAPB20052005
Response
No.
follicles
No.
COC
No.
Embryos
Recovey
Rate %
Low (21%) 8.8a 6.3a 1.8a 72a
Medium (26%) 13.2b 10.4b 2.5b 79
High (19%) 22.4c 18.5c 5.6c 83b
Mixed (34%) 15.1b 12.0d 3.5d 79 a,b,cP 0.05 within a column
Responses among Low, Medium and Responses among Low, Medium and High Responders to OPUHigh Responders to OPU
De Roover et al Theriogenology 2005. 63:1902-1913. De Roover et al Theriogenology 2005. 63:1902-1913.
112 animals, 665 OPU sessions, 5.9 sessions per animal
BrittBrittAAPBAAPB20052005
Variable Control Twinner SEM P <
No. of animals 24 24
Total ovarian wt., g 19.2 26.6 1.3 0.01
No. of small follicles (5 mm) 43.5 60.8 5.1 0.05
No. of medium follicles 3.3 6.4 1.2 0.05
No. of large follicles (10 mm)
1.6 2.5 0.1 0.01
No. of CL 1.1 1.5 0.1 0.01
CL wt., g 2.9 2.6 0.2 NS
Total luteal wt., g 3.0 3.6 0.2 0.05
Echternkamp et al. 2004. JAS 78:1564Echternkamp et al. 2004. JAS 78:1564
Ovarian Characteristics of Cattle Ovarian Characteristics of Cattle Selected or Unselected for TwinsSelected or Unselected for Twins
BrittBrittAAPBAAPB20052005
Stage
Line n Primordial Primary Secondary
Control 7 104.7 58.7 6.3a
Twinner 7 153.7 84.3 12.9b
S.E.M. 27.4 17.3 2.0
a,bP < 0.05 within a column
Preantral Follicles in Cattle Preantral Follicles in Cattle Selected and Unselected for TwinsSelected and Unselected for Twins
Cushman, Hedgpeth, Echternkamp and Britt.2000. J. Anim. Sci. 78: 1564-1567.Cushman, Hedgpeth, Echternkamp and Britt.2000. J. Anim. Sci. 78: 1564-1567.
BrittBrittAAPBAAPB20052005
Environmental Effects on Environmental Effects on Follicle and Oocyte QualityFollicle and Oocyte Quality
Take Home MessageTake Home MessageFolliculogenesis takes months and quality of follicles and oocytes is Folliculogenesis takes months and quality of follicles and oocytes is affected by environmental conditions that exist during this period – affected by environmental conditions that exist during this period –
follicle environment affects oocyte qualityfollicle environment affects oocyte quality..
BrittBrittAAPBAAPB20052005
Hormonal and Other Factors Affecting Hormonal and Other Factors Affecting Number of Follicles and OocytesNumber of Follicles and Oocytes
Trait measured in 1990’s
Adapted from Lucy et al., 1998 and Bonczek et al. ,1988 Adapted from Lucy et al., 1998 and Bonczek et al. ,1988 *1960’s = semen from 1960’s bulls; 1990’s = semen from 1990’s bulls*1960’s = semen from 1960’s bulls; 1990’s = semen from 1990’s bulls
• Milk yield, 305 d, lbs.
• Insulin, µIU/ml
• Somatotropin, ng/ml
• IGF-I before day 14
• IGF-I after day 21
• Progesterone, ng/ml
• Luteal phase, d
16,282
22.5
3.7
lower
higher
4.4
20.0
1960’s Genetics*
21,731
18.8
4.5
higher
lower
3.2
16.6
1990’s Genetics*
BrittBrittAAPBAAPB20052005
Can one grow more follicles by short-Can one grow more follicles by short-or long-term treatment with hormones?or long-term treatment with hormones?
Primordial
FactorsFactors
Steroids Steroids &&
Growth Growth FactorsFactors
Growth Growth FSH & LHFSH & LH
Growth Growth FactorsFactors
FSHFSHGrowth Growth
FactorsFactors
FSHFSH
BrittBrittAAPBAAPB20052005
Long-Term Treatment with Estradiol Long-Term Treatment with Estradiol and bST to Grow More Folliclesand bST to Grow More Follicles
UnilateralOvex.
Con
E2
bST
E2bST 0 50 67
Days from Onset of Treatments
Cushman et al. 2001. BOR 65:851; Cushman et al. 2001. Therio 55:1533Cushman et al. 2001. BOR 65:851; Cushman et al. 2001. Therio 55:1533
Super-ovulate
Treatment with bST and EstradiolTreatment with bST and Estradiol
BrittBrittAAPBAAPB20052005
Serum EstradiolSerum Estradiol
Cushman et al. 2001. Theriogenology 55:1533Cushman et al. 2001. Theriogenology 55:1533
Two CompudoseTwo Compudose™ implants ™ implants inserted on Day 0.inserted on Day 0.
BrittBrittAAPBAAPB20052005
Serum Growth Hormone and IGF-ISerum Growth Hormone and IGF-I
Cushman et al. 2001. Theriogenology 55:1533Cushman et al. 2001. Theriogenology 55:1533
PosilacPosilac™ (500 mg) ™ (500 mg) injected every 14 days.injected every 14 days.
BrittBrittAAPBAAPB20052005
n 0 1 2 3
Control 1620 62.9 32.8 3.0 1.2
E2 1611 48.4 48.0 2.6 1.0
bST 1575 56.7 38.0 3.6 1.7
E2+bST 1887 58.2 37.7 2.6 1.5
Percentages of Follicles within each Percentages of Follicles within each Stage for Cattle Treated for 70 dStage for Cattle Treated for 70 d
Cushman et al. 2001. BOR 65:851; Cushman et al. 2001. Therio 55:1533Cushman et al. 2001. BOR 65:851; Cushman et al. 2001. Therio 55:1533
BrittBrittAAPBAAPB20052005
Number of CL in Cattle Treated with E2, Number of CL in Cattle Treated with E2, bST or the CombinationbST or the Combination
02468
101214161820
Control E2 bST E2+bST
Nu
mb
er o
f C
L
Trial 1
Trial 2
Cushman et al. 2001. Therio 55:1533Cushman et al. 2001. Therio 55:1533
BrittBrittAAPBAAPB20052005
Transferable EmbryosTransferable Embryos
Cushman et al. 2001. Theriogenology 55:1533Cushman et al. 2001. Theriogenology 55:1533
Treatment*Total Ova
TransferableOva
Develop.Rate, %
bST 7.9±1.3a 6.1±1.3a 94±9x
Saline 4.3±1.5b 2.5±1.5b 74±10y
E2 6.8±1.5 4.3±1.5 84±10
Blank 5.4±1.3 4.3±1.3 83±8
a,b P<.01; xy P<.09; Main effects, no interactions.
BrittBrittAAPBAAPB20052005
Transition from FollicleTransition from Follicle to Corpus Luteum to Corpus Luteum
• Provides environment for oocyteProvides environment for oocyte• Secretes estrogen Secretes estrogen • Estrogen causes estrusEstrogen causes estrus• Induces LH surge and ovulationInduces LH surge and ovulation
• Secretes progesteroneSecretes progesterone• Regulates follicle wavesRegulates follicle waves• Regulates embryonic growthRegulates embryonic growth• Required for pregnancyRequired for pregnancy
OvulationOvulation
The The FOLLICLEFOLLICLE is converted to the is converted to the CORPUS LUTEUMCORPUS LUTEUM at ovulation (26-30 hours after onset of estrus).at ovulation (26-30 hours after onset of estrus).
BrittBrittAAPBAAPB20052005
Postpartum Progesterone and Fertility
PostpartumAnestrus
0.0
1.0
2.0
3.0
4.0
5.0
6.0
0 12 24 36 48 60 72 84Days Postpartum
1 2 3
Increasing number and height of profiles is betterbefore AI.
BrittBrittAAPBAAPB20052005
-56 -28 0 28 56 84 112 140Days Postpartum
123456Ovulation No.
Follicle Development During the Postpartum Period
BrittBrittAAPBAAPB20052005
Ovulation No.
-8-6-4-2024
-56 -28 0 28 56 84 112 140Days Postpartum
Energy Balance
123456
Follicle Development and Energy Balance
BrittBrittAAPBAAPB20052005
Progesterone in Cows With Different Body Condition Changes Postpartum
Postpartum Cycle
2
3
4
5
6A
vg.
Lu
teal
Pro
ges
tero
ne,
ng
/mL
1 2 3 4 5
Maintained Condition 5-wk Postpartum
Lost Condition 5-wk Postpartum
BrittBrittAAPBAAPB20052005
0
20
40
60
80
100
Pe
rce
nta
ge
of
Fo
llic
les Calf (6 mo)
Open CowPreg Cow30 d PP Cow
Development of Cultured Preantral Development of Cultured Preantral Bovine FolliclesBovine Follicles
*
*
Figueiredo et al. Theriogenology 42: 1303-1310, 1994.Figueiredo et al. Theriogenology 42: 1303-1310, 1994.
*P < .05
Normal, d 1 Normal, d 5 Growing, d 5
**
BrittBrittAAPBAAPB20052005
Seasonal Differences in Fertility
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec20
25
30
35
40
45
50
55
60
Conception Rate, %
3,200 Primiparous Holstein cows Southern USA3,200 Primiparous Holstein cows Southern USA
BrittBrittAAPBAAPB20052005
Seasonal Differences in P4 Secretion from Dominant Follicle Thecal Cells
050
100150200250300350400
1 2 5 7 9
Day of Culture
P4
ng
/100
,000
cel
ls Winter
Summer
Wolfenson et al. Dom. Anim. Endocrinol. 22: 81-90, 2002.Wolfenson et al. Dom. Anim. Endocrinol. 22: 81-90, 2002.
Cells from Day 6 first wave dominant follicles.Cells from Day 6 first wave dominant follicles.
BrittBrittAAPBAAPB20052005
Seasonal Differences in P4 in Blood and Tissue in Holsteins in Israel
0
1
2
3
4
5
6
7
1 4 7 9 11 13 16 18 20
Day of Cycle
P4
ng
/mL
Winter
Summer
050
100150200250300350400
1 2 5 7 9
Day of Culture
P4
ng
/100
,000
cel
ls Winter
Summer
Effects of differences in P4Effects of differences in P4
Oocyte environmentOocyte environment
Follicle dominanceFollicle dominance
“ “Aged” oocyte and follicleAged” oocyte and follicle
Embryo survivalEmbryo survival
Wolfenson et al. Dom. Anim. Endocrinol. 22: 81-90, 2002.Wolfenson et al. Dom. Anim. Endocrinol. 22: 81-90, 2002.
BrittBrittAAPBAAPB20052005
FSH or bST during One Cycle Improved Oocyte Quality during Next Cycle
0%
20%
40%
60%
80%
100%
Control FSH Control bST
Treatment Groups
Gra
de
1 O
ocy
tes
(%)
Roth et al. J. Dairy Sci. 85: 1398-1405, 2002.Roth et al. J. Dairy Sci. 85: 1398-1405, 2002.
Holstein cows – Holstein cows – heat stressedheat stressed in Israel in summer and treated in Oct or Nov in Israel in summer and treated in Oct or NovAll visible follicles aspirated on Day 4 of Cycle 1 and Cycle 2All visible follicles aspirated on Day 4 of Cycle 1 and Cycle 2
1 2 21 21 21
Control vs FSHControl vs FSH2 x 200 mg of FSH2 x 200 mg of FSHDay 5 & 12 of Cycle 1Day 5 & 12 of Cycle 1
Control vs bSTControl vs bST500 mg Somatech (Posilac)500 mg Somatech (Posilac)Day 4 & 18 of Cycle 1Day 4 & 18 of Cycle 1
BrittBrittAAPBAAPB20052005
Not All Studies Show An Effect of bST on Number of Oocytes or Embryos
0
2
4
6
8
10
12
Cycle 1 Cycle 2 Cycle 3 Cycle 4
To
tal E
mb
ryo
s an
d O
ocy
tes
rbST
Control
0
1
2
3
4
5
6
Cycle 1 Cycle 2 Cycle 3 Cycle 4
Tra
nsfe
rab
le E
mb
ryo
s rbST
Control
Hasler et al. 2003. Theriogenology 59: 1919-1928.Hasler et al. 2003. Theriogenology 59: 1919-1928.
•57 primiparous Angus cows57 primiparous Angus cows•Four consecutive superovulation cyclesFour consecutive superovulation cycles•500 mg rbST every 14 days500 mg rbST every 14 days
BrittBrittAAPBAAPB20052005
Thank You !
The University of Tennessee’s Cloned Jersey HeifersThe University of Tennessee’s Cloned Jersey Heifers