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Abstract
Phenobarbital is a barbiturate derivative commonly used nowadays for its wide clinical spread and applications as an anticonvulsant. The concurrent study clarified the structural changes of different elements of testis and the (injurious) effect of phenobarbital in different post natal age groups for different periods.
Thirty five male albino rats of Sprague-Dawley strain weighting (55-85) gms were used in the present study.
At the start of the experiment three rats aged 3 weeks (age of weaning )were sacrificed to study their testicular structure then, the rest of the three weeks old rats were divided into 4 age groups ,each group consisted of 8 rats (3 controls and 5 treated ) .
Group I: included animals aged 5 weeks, received therapeutic dose of phenobarbital orally for 2 weeks.
Group II: Include animals aged 7 weeks, received therapeutic dose of phenobarbital orally for 4 weeks.
Group III: Include animals aged 12 weeks, received therapeutic dose of phenobarbital orally for 9 weeks.
Group IV: Include animals aged 14 weeks, received therapeutic dose of phenobarbital orally for 9 weeks followed by 2 weeks stoppage of treatment to study the recovery effect.
All groups had received daily dose of 80 mg/kg/body weight/day of phenobarbital orally by gastric intubation (dissolved in distilled water).
At the end of each experimental period the animals sacrified by anesthesia (diethyl ether), and they were immediately dissected and the testes of all animals was obtained for histological study using light micrsocopy (the specimens of the right testis stained with haematoxylin and eosin and those of the left testis processed to get semithin sections and stained with toluidine blue.
The post natal developmental changes of different elements of testis of albino rat in different age groups were examined and revealed that:
The pre pubertal stage (rat testis aged 3 weeks and five weeks) showed in the 3rd week the predominant cells were the spermatogonia and primary spermtocytes,
In the Fifth week the rounded spermatids started to develop while elongated spermatids were hardly detected together with poorly developed Leydig cells.
The puberty stage was reached at 7th week as the rounded spermatids transformed to elongated spermatids and fully formed sperms filled the lumen of the seminiferous tubules and increase number of well developed generations of Leydig cells were also detected in the interstitial tissue.
The adult stage was reached at 12th week It was characterized by increased number of elongated spermatids, whorlly appearance of sperms in the lumen and mature Leydig cells in the interstitial space.
The effect of phenobarbital on group( I) (5 weeks rat received phenobarbital for 2 weeks only) was mild as there were mild damage of the seminiferous tubules. The basement membrane was thin and festooned. Mild depletion of the spermatogenic cells, mild intercellular vacuolation with few spermatogenic cells (primary spermatocytes) showed deeply stained nuclei.
The effect of phenobarbital on group( II) (7 weeks rat received phenobarbital for 4 weeks) was massive damage and shrinkage of the seminiferous tubules. The basement membrane was highly thickened and corrugated. Marked depletion of the spermatogenic cells (primary spermatocytes, rounded and elongated spermatids). Multiple large intercellular vacuolation was obvious, degeneration of almost all of the spermatogenic cells which showed loss of cell boundaries loss of nuclear details, deeply stained nuclei or hyperchromatic nuclei, intracytoplasmic vacuolation, granulations associated with decreased elongated spermatids. Also, there were exfoliated degenerated spermatogenic cells in the lumen. Lipid DROPlets were detected near the degenerated Sertoli cells which showed deeply stained nuclei, Leydig cells showed shrunken nuclei.
The effect was moderate on group III (12 weeks adult rats received phenobarbital for 9 weeks). The affection of the seminiferous tubules was variable some were collapsed and shrunken while others were massively distorted and ruptured. The seminiferous tubules showed the same changes observed in the previous age group but in moderate degree. Leydig cells also acquired a fibroblast like appearance, peripheral linear arrangement of the nuclear chromatin.
The recovery after 2 weeks stoppage of the phenobarbital treatment was examined and revealed that few seminiferous tubules showed signs of regeneration as there was decrease in the intercellular vacuolation, increase of the rounded elongated, spermatids and sperms and Leydig cells return to normal appearance. While the other seminiferous tubules still have degenerated spermatogenic cells and exfoliated degenerated cells in the lumen and reduction in the elongated spermatids which indicate the incomplete recovery of the seminiferous tubules.