Balb/C türü dişi farelerde uniseksüel gruplamanın östrus siklusu üzerine etkileri

Sosyal çevreye ait uyarıcılar farelerde östrus siklusunun frekansını ve düzenini etkiler. Kalabalık halde bırakılan dişi farelerin çoğu spontan yalancı gebelik ya da persis-tent diöstrus gösterme eğilimindedir. Bu yüzden dişi fareler arasındaki ilişkiler onların kafesleme koşullarını belirleyen önemli bir faktör olarak dikkate alınmalıdır. Bu çalışmada amacımız; Balb/c türü dişi farelerde kafes popülasyonu yoğunluğunun östrus siklusu ve vajinal sürüntü sitolojisi üzerine etkilerini incelemektir. Hayvanlar bir kafeste iki (Set I, n=40) ya da sekiz fare (Set II, n=40) olacak şekilde kafeslenerek 2 deney seti oluşturuldu. Her bir dişi farenin östrus durumu, 15 gün boyunca her sabah standart vajinal sürüntü metoduyla tespit edildi. İki dişi/kafes grubunda ortalama 4-5 günlük düzenli sikluslar gözlenirken, 8 dişi/kafes grubunda uzayan sikluslar tespit edildi. Set I grubunda her faza ait vajinal sürüntü histolojisi normal hücre popülasyonunu sergilemekte idi. Kalabalık kafes popülasyonunda ise nötrofillerden ve mukustan zengin sürüntüler elde edildi. Deney süresince Set II grubunda östrus ve proöstrus faz frekansları anlamlı oranda azalırken, diöstrus frekansı belirgin derecede artmıştı. Aynı şekilde diöstrus indeksi-nin de Set II grubunda Set I grubundan anlamlı oranda yüksek olduğu gözlendi. Sonuç olarak, elde ettiğimiz bulgular Balb/c türü dişi fareler kullanılırken, östrus senkronizasyonu için kafes yoğunluğunun 2 dişi/kafes şeklinde düzenlenmesi ile hem düzenli siklusların hem de normal vajinal sürüntü histolojisinin elde edilebileceğini göstermektedir.

Effects of unisexually grouping on the estrous cycle regulation in balb/c female mice

Stimuli from social environment influence both the frequency and regularity of the estrous cycle in the mouse. The most of the unisexually grouped females tend to show spontaneous pseudopregnancies or persistent diestrous. Therefore, relationship among the female mice should be considered as a determining factor of housing conditions in the experimental studies. We aimed to investigate the effects of density of cage population on the estrous cycle and the vaginal smear in Balb/c female mice. Two sets of animals were placed in two (Set I, n=40 ) and eight (Set II, n=40) females per cage. The estrous status of each female mouse was determined each morning for 15 days by the standard vaginal smear method. Animals showed 4-5 days regular cyles in 2/cage group while prolonged cycles was observed in 8/cage group. Histology of vaginal smears represented normal cell populations of each respective estrous cycle phases. However, smears of multiply housed mice were mostly with mucus and leucocytes. Estrous cycle was affected by showing a significant decrease in the frequency of proestrous and estrous and with concomitant significant increase in the frequency of diestrous in all the Set II females, throughout the experiment. Similarly, the diestrous index of Set II group was significantly greater than Set I group. In conclusion, these results support that cage density as two female per cage can contribute to obtain both regular estrous cycles and histology of normal vaginal smear in Balb/c female mice for synchronization of estrous.

Kaynakça

1. van der Lee, S. & Boot, LM. Spontaneous pseudopregnancy in mice. Acta Physiol Pharmacol Neerl 1955;4: 442-4.

2. van der Lee, S. & Boot, LM. Spontaneous pseudopregnancy in mice II. Acta Physiol Pharmacol Neerl 1956;5: 213-5.

3. Whitten WK. Occurrence of anoestrus in mice caged in groups. J Endocr 1959;18,102-7.

4. Champlin AK. Suppression of oestrus in grouped mice: the effects of various densities and the possible nature of the stimulus. J Reprod Fertil 1971;27: 233-41.

5. Campbell CS, Ryan KD, Schwartz NB. Estrous cycles in the Mouse: relative influence of continuous light and the precence of male. Biol Reprod 1976;14: 292-9.

6. Singletary SJ, Kirsch AJ, Watson J, Karim BO, Huso DL, Hurn PD, et al. Lack of correlation of vaginal mpedance measurements with hormone levels in the rat. Contemp Top Lab Anim Sci 2005;44: 37–42.

7. Dalal SJ, Estep JS, Valentin-Bon IE, Jerse AE. Standardization of the Whitten effect to induce susceptibility to Neisseria gonorrheae in female mice. Contemp Top Lab Anim Sci 2001;40: 13–7.

8. Pasley JN, Rank RG, Hough AJ Jr, Cohen C, Barron AL. Effects of various doses of estradiol on chlamydial genital infection in ovariectomized guinea pigs. Sex Trans Dis 1985;12: 8–13.

9. Carswell HV, Anderson NH, Clark JS, Graham D, Jeffs B, Dominiczak AF, et al. Genetic and gender influences on sensitivity to focal cerebral ischemia in the stroke-prone spontaneously hypertensive rat. Hypertension 1999;33: 681–5.

10. Allen E. The oestrous cycle in the mouse. Amer J Anat 1922;30: 297-371.

11. Kanter M, Öztaş E, Dalçık C. Sıçan, fare ve kobaylarda gebeliğin ilk gününü tayin etmede vaginal sürüntü yönteminin kullanılması. Van Tıp Dergisi 1996;3: 112-6.

12. Grasso P, Reichert LE. In vivo effects of follicle-stimulating hormone-related synthetic peptides on the Mouse estrous cycle. Endocrinol 1996;137: 5370-5.

13. Sahu A and Ghosh A. Effect of grouping and sex on the estrous regulation of a wild rat, bandicota bengalensis. Biol Reprod 1982;27: 1023-5.

14. Hiremath MB, Kaliwal BB. Effect of endosulfan on ovarian compensatory hypertrophy in hemicastrated albino mice. Reprod Toxicol 2002;16: 783-90.

15. Rao RP, Kaliwal BB. Monocrotophos induced dysfunction on estrous cycle and follicular development in mice. Ind Health 2002;40: 237-44.

16. Bruce HM. A block to pregnancy in the mouse caused by proximity of strange males. J Reprod Fertil 1960;1: 96-103.

17. Berry ML, and Linder CC. Breeding Systems: Considerations, Genetic Fundamentals, Genetic Background, and Strain Types. In: The Mouse in Biomedical Research. Fox JG, Davission MT, Quimby FW, Barthold SW, Newcamer CE, Smith AL (Eds). Vol I. Chapter 4. 2. nd. edition. USA: Elsevier; 2007: 54-5.

18. Lamond DR. Effect of stimulation derived from other animals of the same species on oestrous cycles in mice. J Endocrinol 1959;18: 343-9.

19. Nelson JF, Felicio LS, Randall PK, Sims C, Finch CH. A longitudinal study of estrous cyclicity in aging C57BL/6J Mice: I. Cycle frequency, length and vaginal cytology. Biol Reprod 1982;27: 327-39.

20. Jemiolo B, Harvey S, Novotny M. Promotion of the Whitten effect in female mice by synthetic analogs of male urinary constituents. Proc Natl Acad Sci USA 1986;83: 4576-9.

21. Morè L. Mouse major urinary proteins trigger ovulation via the vomeronasal organ. Chem Senses 2006;31: 393-401. Epub 2006 Mar 1.

22. Bronson FH. Rodent pheromones. Biol Reprod 1971;4: 344-57.

23. Gangrade BK, Dominic CJ. Studies of the male-originating pheromones involved in the Whitten effect and Bruce effect in mice. Biol Reprod 1984;31: 89-96.

24. Ma W, Miao Z, Novotny MV. Induction of estrus in grouped female mice (Mus domesticus) by synthetic analogues of preputial gland constituents. Chem Senses 1999;24: 289-93.

Kaynak Göster