'In vitro' capacitation and acrosome reaction are concomitant with specific changes in mitochondrial activity in boar sperm: evidence for a nucleated mitochondrial activation and for the existence of a capacitation-sensitive subpopulational structure.
The main scope of this manuscript is to analyse the dynamics of mitochondrial activity in boar sperm subjected to 'in vitro' capacitation (IVC) and subsequent progesterone-induced 'in vitro' acrosome reaction (IVAR). This was determined after analysis of the rhythm of O(2) consumption and concomitant changes in the mitochondria activity-specific JC-1 staining. Results showed that IVC, and especially IVAR, was concomitant with a peak in O(2) consumption (from 1.61 ± 0.08 nmol O(2)/min/10(7) viable sperm at 0 h of incubation to 2.62 ± 0.12 nmol O(2) /min/10(7) viable sperm after 5 min of IVAR induction). These results were accompanied by parallel changes in the mean intensity of JC-1 staining. Based on JC-1, mitochondrial activation followed a nucleated pattern, with specific, activation starting points at the midpiece from which mitochondrial activation was spread. Moreover, four separate sperm subpopulations were detected following the JC-1 orange-red/green ratio, and the observed changes in the mean JC-1 staining during IVC and IVAR were related to concomitant changes in both the orange-red/green JC-1 ratio and the percentage of sperm included in each subpopulation. All of these results indicate that IVC and the first minutes of IVAR are accompanied by a progressive increase in mitochondrial activity, which reached a peak coincidental with the achievement of IVAR. Moreover, results suggest the presence of separate sperm subpopulations, which show a different mitochondrial sensitivity to IVC and IVAR. Finally, mitochondrial activation, at least under JC-1 staining, seems to originate in concrete nucleation points at the midpiece, thus suggesting thus a well-coordinated pattern in boar-sperm mitochondrial activity modulation.
Department of Animal Medicine and Surgery, School of Veterinary Medicine, Autonomous University of Barcelona, Bellaterra, Spain.
L
L
Ramió-Lluch
J M
JM
Fernández-Novell
A
A
Peña
C
C
Colás
J A
JA
Cebrián-Pérez
T
T
Muiño-Blanco
A
A
Ramírez
I I
II
Concha
T
T
Rigau
J E
JE
Rodríguez-Gil
D020101:Acrosome Reaction / Q000502:physiology*; D000818:Animals; D008297:Male; D008928:Mitochondria / Q000502:physiology*; D010101:Oxygen Consumption; D011374:Progesterone; D013075:Sperm Capacitation / Q000502:physiology*; D013094:Spermatozoa / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D013552:Swine / Q000502:physiology*
D011374:Progesterone