الفهرس Only 14 pages are availabe for public view
 |  | from | 96 |  |  |
| | | from | 96 | | |
Abstract
Summary:-In order to clarify the possible physiological role of endogenous opioid peptides, the present study was carried out to study the effect of opioid antagonist administration on some reproductive parameters in adult male rats.
The study was carried out at the Department of Physiology, Faculty of Veterinary Medicine, Zagazig University.
Fourty mature male albino rats were divided into 4 equal groups. Group I maintained as control. Group II was subjected to restraint stress 1 hour each day for 2 weeks. Group III was injected intraperitoneal with the opioid antagonist (Naltrexone) in a dose of 1.5 mg/kg 30 minutes prior to each stress session. Group IV was injected only with Naltrexone at the same dose. After one week, half of the animals in each group was sacrified and the other half was sacrified after two weeks.
Blood samples were collected at the time of sacrifying in tubes without anticoagulants for obtaining serum to be used for estimation of testosterone and prolactin levels.
Testes were carefully exiced and mixed with physiological saline then homogenized to obtain the supernatant which is handled exactly as the semen for examination of semen picture.
Furthermore, histopathological examination of testis was performed.
The obtained results revealed the following:
I-Serum testosterone level
The study revealed a significant decrease in serum testosterone level in immobilization stress group either after one or 2 weeks (0.92±0.09 ng/ml and 0.93±0.33 ng/ml) comparing to the control group (4.12±0.54 ng/ml and 3.09±0.05 ng/ml after one and 2 weeks, respectively). While Naltrexone administration before exposure to stress modified serum testosterone level (2.83±0.38 ng/ml and 3.52±0.61 ng/ml after one and 2 weeks, respectively). In NTX-treated group, there was a significant increase in serum testosterone level either after one or 2 weeks (5.19±0.67 ng/ml and 5.07±0.27 ng/ml).
II- Semen picture
a- Sperm motility percentage.
There was a significant reduction in motility% from control group (92.50±1.44% and 90.00±2.88% after one and 2 weeks, respectively) to (73.75±4.73% and 73.33±3.33% after one and 2 weeks, respectively) in immobilization stress group. While the decrease in motility% was blocked by NTX administration before application of stress(90.00±2.04% and 86.67±3.33% after one and 2 weeks, respectively).
b- Sperm cell concentration.
Sperm cell concentration showed decrease in immobilization stress group either after one or 2 weeks (40.25±3.19/ml x 125 x 104 and 35.00±2.88/ml x 125 x 104) as compared to the control group (47.50±3.17/ml x125 x 104 and 82.67±23.05/ml x 125 x 104). NTX administration before exposure to stress prevent the decrease in sperm cell concentration caused by stress (54.75±11.05/ml x 125 x 104 and 60.50±9.13/ml x 125 x 104 after one and 2 weeks, respectively).
c- Sperm abnormalities percentage.
The immobilization stress group showed a significant increase in abnormalities % after one week (26.25± 3.66%) as compared to the control group after the first week (9.25 ± 1.93% ) and this percentage showed more increase after 2 weeks in stress group (32.75±4.13 %) when compared to the control group after 2 weeks (12.00±1.00%). While NTX administred before stress prevent the modification in sperm abnormalities percentage caused by stress (11.50±1.19%and 10.50±1.19% after one and 2 weeks, respectively).
III- Serum prolactin level
The study revealed a significant increase in serum prolactin level after the first week in immobilization stress group (0.391±0.07 ng/ml) when compared to the control group (0.109±0.01 ng/ml) while NTX was capable of attenuation of the increase in serum prolactin level caused by stress in the first week (0.156±0.03 ng/ml) and it is more obvious after 2 weeks (0.078±0.03 ng/ml).
IV- Histopathological examination of testes
There was normal histopathological picture of testis in control group. While in immobilization stress group, the testis showed severe necrosis of large number of seminiferous tubules with desquamated spermatogenic cells inside the lumen. In NTX+stress group, the testis showed normal spermatogenic cells inside the seminiferous tubules. In NTX-treated group, there was an increase in the number of leydig cells as well as in the number of spermatozoa.