Histological and histochemical changes in the ovary of immature female albino rat after injection of human chorionic gonadotropin [pregnil]

ABSTRACT

Thirty immature 24 days old female albino rats were used in this study. They were classified into 4 groups [A, B, C and D]. Group A comprised 15 rats and was used as a control. Group B, C and D, each comprised 5 rats were injected intraperitonealy with 25 IU of HCG [pregnil] for each rat. Group B was sacrificed 2 days after injection. Group C was sacrificed after 5 days and group D was sacrificed after 10 days. Five control rats were sacrificed with each group respectively. Each ovary of all groups was weighed after cleaning of its surrounding. Paraffin sections 6 micro, m in thickness were prepared and stained with HX and E, and PAS reaction. Another paraffin sections 10 micro, m in thickness were prepared and stained for alkaline phosphatase activity by Gomori calcium cobalt method. In HX and E stained sections the number of granulosa cell layers present in the growing follicles were calculated and diameters of the corpora lutea were measured. All these data were statistically analyzed. Inimmature control ovaries of 26 and 29 days of age there was no histological differences between the two age groups. The cortex, contained primordial follicles, growing follicles of solid nature and small antral follicles with granulosa cells 2 to 4 layers in thickness. In 34 days old control rats the ovary contained more antral follicles than growing follicles. Granulosa cells was 3 to 5 layers. All controls had no mature Graafian follicles or corpora lutea. After 2 days of HCG administration [GP B], the growing follicles increased in number and became larger in size and its granulosa cell layers increased in number. The mature Graafian follicles began to appear and no corpora lutea were found. After 5 days from administration of the drug [GP C], the ovaries showed many corpora lutea, many cysts and partly lutinized follicles, the medulla was engorged, with dilated and congested blood vessels. Also haemorraghic cysts appeared. After 10 days of HCG administration [GP D] the ovaries showed the same criteria as 5 days administration but less pronouced and with more atretic follicles. Regarding PAS reaction; in control group, only the zona pellucida of the growing follicles revealed a strong positive reaction but in the drug injected groups positive reaction appeared in the growing follicles, mature Graafian follicles and corpora lutea. Some follicles showed two zona pellucida indicating the presence of two primary oocytes in the same follicles. Considering the alkaline phosphatase activity, It was found that the ovaries of the control groups were inactive except for the blood vessels and the growing follicles which showed some activity. But in the drug injected groups the activity were found in the growing follicles, mature Graafian follicles and corpora lutea