TESTOSTERONE EFFECT ON IMMATURE RAT OVARIES
Vanja Radić¹, Jagoda Roša², Ana Borovečki¹, Anita Škrtić¹, Lea Sokolić³
¹Department of GY&OB and Gynaecological Pathology, University Hospital Merkur, ²Department of Physiology, School of Dentistry and Medicine, University of Zagreb ³Endocrinologic Laboratory, University Hospital Vuk Vrhovec, Zagreb, Croatia
There are several animal models that were experimentally induced for evaluation of metabolic and endocrine pathophysiologic pathways of the polycystic ovaries syndrome.
We performed a practical rat model for the syndrome using available testosterone depot oil solution that induces chronic hyperandrogenemy. The effect on ovulation cycles on immature female rats (3 weeks old) was evaluated as we injected testosteronenantat im. 0,1 mg per 1 gram of body mass or the same amount of ricinus oil for the control group (6 groups per 6 animals). The injections were repeated weekly with corrected dose according to the body weight. The groups of rats were sacrificed after 3, 4 and 5 weeks of treatment. Blood samples were obtained for the progesterone serum values and ovaries were obtained for pathohystologic evaluation.
The experiment confirmed that chronic hyperandrogenemy induces the formation of polycystic ovaries. Pathohystology revealed apoptosis of preantral follicles and formation of follicular cysts with apoptosis in stratum granulosum without development of corpora lutea.The serum progesterone values were significantly lower in comparison to control animals (р<0,05).
Induced hyperandrogenemy revealed pathohystologic result of typical polycystic ovaries compared to humans. The low progesterone serum values confirmed chronic anovulation. We invented this model for further experimental analysis of the pathophysiology of the syndrome.
Table 1
Daily body weight gain (grams per day) men value (+/- SEM) in groups during testosteronenantat treatment of female rats and controls; p=0,026.
Treated animals / Control animals21 days / 4,48 +/- 0,27 / 4,50 +/- 0,36
28 days / 4,71 +/- 0,44 / 4,11 +/- 0,46
35 days / 4,20 +/- 0,46 / 4,11 +/- 0,64
Table 2
Statistical analysis of the progesterone serum values (nmol/L) in testosteronenantat treated rats and controls (U* - Mann Whitney U test, sd – standard deviation)
Group / Treated animals / Control animals / U* / pMean / sd / Median / Range / Mean / sd / Median / Range
21 days / 22,0 / 10,2 / 21,0 / 9,8-36,8 / 69,8 / 34, / 77,9 / 21,9-104,0 / 3 / 0,016
28 days / 12,5 / 5,0 / 11,7 / 7,6-19,3 / 90,4 / 21,9 / 88,3 / 61,8-122,0 / 0 / 0,002
35 days / 10,4 / 4,3 / 11,3 / 3,0-14,7 / 21,8 / 5,1 / 21,3 / 15,8-30,5 / 0 / 0,002
Friedman X2 =4,33 p=0,115 / Friedman X2 =6,33 p=0,042
Figure 1
Histological features of rat ovaries after 21 (A), 28 (B) and 35 (C) days of testosteronenantat treatment / 42 (A), 49 (B) and 56 (C) days old rats (x 4 obj).
The rat ovaries are loaded with preantral follicles (PAF), with large cystic follicles (CF). Ovarian stroma is enlarged (arrow), no corpora lutea. Ovarian stroma is enlarged (arrow).
Figure 2
Histological features of normal rat ovaries (control group) after 21(A), 28(B) and 35(C) days of experiment / 42 (A), 49 (B) and 56 (C) days old rats (x 4 obj).
There are mainly small and medium sized antral follicles (AF) and corpora lutea (CF).
Figure 3
Histological features of rat ovaries after testosteronenantat treatment (x 10 obj).
(A, B) Part of the ovary 21 days after treatment / 42 days old rats; apoptotic cells in inner layers of stratum granulosum of cystic follicle and in antral follicle. (C) 28 days after treatment / 49 days old rats; preservations and coupling of primordial follicles (arrow) and primary follicles (PF). (D) Antral follicle - oocite shows degenerative changes (wide arrow left) and (E) part of cystic follicle with abundant apoptotic cell (wide arrow right).