Pengaruh Kegiatan Olahraga Berat terhadap Siklus Estrus dan Kemampuan Reproduksi Mencit (Mus musculas) Strain DD Webster

Abstract

Cross sectional or retrospective study indicates that the frequency of reproductive cycle disorders and the decrease in reproductive performance are tended to higher in women athletes than non athletes one. However, the available experimental data originated from both animal models and human being are not sufficiently support those cross sectional or retrospective data. In fact, those experimental data are required in order to determine a suitable type of sports and training portion for women without any negative impacts on its reproductive function. This research was aimed to study experimentally the effect of heavy physical activity on estrous cycle and reproductive performance of female mammals. To achieve this aim, fourty virgin, sexually mature and normally cycling female DD Webster mice (Mus musculus) were obtained. All mice were preexperimentally trained to run for 30 minutes a day for 7 consecutive days on a specially designed treadmill (0o inclination) with a grad:ualy increased speeds from 5, 10,20,30 to 40 m/minute for 5 minutes each speed. Trained mice were then randomly distributed on the control or treatment group, 20 mice each. During the experiment period, the treatment group of mice was treated with a heavy and chronic physical activity in the form of run on the same treadmill for 8 consecutive weeks, 2 hours aday (08.00 to 10.00 AM) and 5 days a week. Each physical activity unit was initiated with a warming period (20 minutes), and then followed by aheavy physical activity (80 minutes), and finally terminated with a relaxation period (20 minutes). During warming period, mice were run on the treadmill with a gradually increased speed from 5, 10, 20 to 30 m/minute, 5 minutes for each speed. After warming period, mice were forced with a heavy physical activity of 80 minutes run on treadmill with a single speed of 40 m/minutes and then directly terminated with a relaxation period consisted of a gradually decreased speed of treadmill, from 30, 20, 10 to 5 m/minute for 5 minutes per speed. control group was applied with a light physical activity, i.e. run on treadmill with a single speed of 9 m/minute for 15 minutes, 3 days per week for 8 consecutive weeks. During experiment period, atl mice were maintained in an individual cage, supplied daily with a commercial pellet (6 g/mouse/day) and water (6 ml/mouselday), weighed and checked for estrous cycle by means of vaginal smear examination. Daily residual food and water was firstly measured and expelled from containers before a new and fresh one was supplied. One day after treatment, female mice were caged overnight with proven fertil male (1 : 1) for 7 consecutive days (mating test), and checked daily for the presence or absence of vaginal plug, or of sperm in vaginal smear. These data were needed for the determination of copulation, fertility and pregnancy rates. Both mated (plug or sperm positive) and unmated female mice (plug or sperm negative) were caged individually until the end of mating period, and at 18th days old of pregnancy (hk-18) the uterus were analysed for the determination of reproductive performance. The observed data show that the heavy physical activity treatment applied daily and chronically for a long term significantly decreased body weight. This was initiated by a significant decrease in food consumption and an increase in water consumption. Treatment was also effectively induced a prolongation of estrous cycle which was manifested in a significant decrease number of cycle that can be observed during the 8 weeks of experimental period. The changes in cycle pattem was primarily due to the prolongation of diestrous and concomitantly with the diminishion of proestrous and estrous stages of the cycle. The concequence of physical activity-related change in estrous cycle was the decrease in female mating capacity that was indicated by a significant prolongation of copulation time without any significant changes in pregnancy and fertility rates. At the ovarian and uterine levels, treatment was very significantly decrease both the number of implantation and fertilisation rate, and this in furn decreases the number of life fetuses, without any interference in ovulation rate in the two ovaries (as indicated by the number of corpora lutea of pregnancy). The decrease in both the number of implantation and feftilisation was primarily due to a very significant increased in preimplantation loss of ova. No significant changes were observed in fetal size and sex ratio or at the ovarian and uterine histological levels. These results indicate that a daily and long term heavy physical activity that applied chronically can disturb estrous cycle. This disturbance can be resulted in the decrease in reproductive performance without any interference in ovulation capacity of female mice. These experimental data could be used as an invaluable reference to describe the data from cross sectional study on the high frequency of disturbance in female menstrual cycle and reproductive function. The results could also be used as a important input for further study in the determination of both sport type and training portion that safe for healthy reproduction in female athletes