The effect of the genital fluids of the ewe on the metabolism of ram spermatozoa.

Abstract

THE EFFECT OF GENITAL FLUIDS OF THE EWE ON THE METABOLISM OF RAM SPERMATOZOA B. J. RESTALL* I. INTRODUCTION At the present time the role of the fluids from the female genital tract is largely unknown. Most attempts to elucidate this role have been carried out in the rabbit and cow (Bishop 1956, 1957; Clewe and Mastroianni 1959; Mastroianni and Wallach 1961; Mastroianni et al 1961; Olds and Van Demark 1957). No reports on the effect of the genital fluids of the ewe on the metabolism of ram spermatozoa are available and this paper contains some preliminary observations. II. MATERIALS AND METHODS (a) Collection of the fluids Follicular and uterine fluids were collected by aspiration from 300 reproductive tracts obtained from the N.S.W. State Abbatoir, Homebush. The tracts were classified into three groups corresponding approximately to the physiological states of oestrus, metoestrus, and dioestrus, using the data given by Restall (1964). Oviducal fluid was obtained from two ewes with cannulated oviducts. Cervicovaginal fluid was obtained by aspiration from the vaginas of eight oestrus ewes. (b) Measurement of oxygen uptake of the spermatozoa Ram spermatozoa were washed twice in Mann' semen diluent (Mann 1954)' s suspended in the fluids and the oxygen uptake measured at 37 -5�C in Warburg apparatus. Readings were made at 10 min intervals for 90 min. Controls containing saline instead of spermatozoa and saline instead of genital fluid were used to make corrections for the metabolic activity of the fluids alone and the spermatozoa alone. The significance of the results was assessed by analysis of variance. III. RESULTS (a) Experiment 1 Vaginal, follicular, uterine and oviducal fluids from ewes in different stages of the oestrous cycle were pooled and incubated with 5 -0 x 10s live spermatozoa. The oxygen uptake is shown in Figure 1. There were significant differences (P<O*Ol) between fluids and between times. All fluids caused an increase in the oxygen consumption of the spermatozoa with follicular and cervico-vaginal fluids having a significantly greater effect than oviducal and uterine fluids. Oviducal fluid had a significantly greater effect than uterine fluid. *School of Wool Technology, The University of New South Wales. 29 Fig. l.- Oxygen uptake of spermatozoa in fluids from the genital tract of the ewe. In all the fluids there was a gradual decline in the oxygen uptake of the spermatozoa with time. (b) Experiment 2 Follicular fluids from ewes in the oestrus, metoestrus and dioestrus were incubated with two spermatozoa samples (approximately 4 3 x 10s live cells per flask). l The oxygen uptake is shown in Figure 2. Follicular fluid from oestrous and metoestrous ewes gave a significantly (P<O-01) greater stimulus to the metabolism of the spermatozoa than did the same fluid collected from dioestrous ewes. The difference between oestrous, metoestrous and dioestrous fluids was greater in one semen sample than in the other. In one semen sample oxygen uptake gradually declined with time but did not do so in the other. Both these interactions were significant (P<O-01 and P<O-05 respectively). IV. DISCUSSION These findings suggest that the fluids examined may have some function in the physiology of spermatozoa deposited in the female genital tract. Austin ( 195 1) and Chang (195 1) have shown that rabbit and rat spermatozoa are unable to fertilize ova until' after a period of incubation in the female reproductive tract. Austin (1952) has termed this phenomenon 'capacitation' and Mattner (1963) estimates the time required for capacitation to occur in the sheep to be 11% hours. The exact changes in the spermatozoa attributable to capacitation are unknown but these results suggest that the fluids of the female genital tract may be important 30 31 in this respect. Follicular fluid undergoes modification at the time of fertilization and the resulting fluid environment may also assist the process of capacitation. The different effects on the metabolism of spermatozoa shown by each fluid suggest that each organ may have a particular role in the physiology of spermatozoa prior to fertilization. The uterus can act as a reservoir for spermatozoa (Mattner 1963) and the lower stimulus of uterine fluid may be important in the survival of the spermatozoa. V. REFERENCES , C. R. (1951). Observations on the penetration of the sperm into the mammalian egg duct. Australian Journal of Scientific Research B. 4: 581. A USTIN , C. R. (1952). The capacitation of the mammalian sperm. Nature 170: 326. A USTIN , D. W. (1956). Active secretion in the rabbit oviduct. American Journal of Physiology 187: 347. B ISHOP , D. W. (1957). Metabolic conditions within the oviduct of the rabbit. International Journal of Fertility 2: 11. C HANG , M. C. ( 195 1). Fertilizing capacity of spermatozoa deposited into the fallopian tubes. Nature 168: 697. C LEWE , T. W., and M ASTROIANNI , L. (1959). A method for the prolonged collection of secretions from the oviducts of unanaesthetized rabbits. Anatomical Record 133: 261. M ANN , T. (1954). The Biochemistry of Semen. Methuen, London. M ASTROIANNI , L., and W ALLACH , R. C. (1961) . Effect of ovulation and early gestation on oviduct secretions in the rabbit. American Journal of Physiology 2,010: 815. M ASTROIANNI , L., B EER , F., S HAH , U., and C LEWE , T. H. ( 1961). Endocrine regulation of oviduct secretion in the rabbit. Endocrinology 68: 92. M ATTNER , P. ( 1963a). Spermatozoa in the genital tract of the ewe. IL. Distribution after coitus. Australian Journal of Biological Science 16: 688. M ATTNER , P. (1963b). Capacitation of ram spermatozoa and penetration of the ovine egg. Nature 199: 772. O LDS , D., and V AN D EMARK , N. L. ( 1957). The behaviour of spermatozoa in the lumenal fluids of bovine female genitalia. American Journal of Veterinary Research 18: 603. RESTALL, B. J. ( 1964). The growth and retrogression of the corpus lutem in the ewe. AusB ISHOP tralian Journal of Experimental AgricuZture and Animal Husbandry: 4: 274. 32