Histological and ultrastructural changes of the thyroid follicles after injection of vitamin C in aged male albino rats

This study was conducted to investigate the effect of vitamin C administration on the structure of thyroid follicles in aged albino rats. Forty eight male albino rats were used in this study. They were divided into two groups [24 adult and 24 aged]. Each group was divided into 3 subgroups [8 animals served as controls, 8 animals received intramuscular [i.m.] injection of 50 mg/kg/day vitamin C and 8 animals received i. m. injection of 100 mg/kg/day vitamin C]. After three weeks all animals were sacrificed. The thyroid gland was dissected out and prepared for light and electron microscopic examination. Morphometric studies were done to compare the diameter of the follicles and the height of the follicular cells in the different groups. Histological examination and morphometric studies revealed that extremely large follicles appeared in the aged rats. These follicles were lined by attenuated follicular cells. Electron microscopic examination revealed that the cytoplasm of the follicular cells was occupied by dilated rough endoplasmic reticulum, secondary 1ysosomes and large number of cytoplasmic vacuoles that contained colloidal material. On the other hand, sections of aged animals that were injected with vitamin C showed some improvement in the follicular structures. Moreover, the follicular cells became nearly similar to the adult control group. These results provided evidence that supplementation of antioxidant vitamin C could play an important role in the modulation of the thyroid changes that were associated with aging

Histological study of the effect of transient neonatal hypothyroidism on the testes of albino rats

Recognition and treatment of childhood hypothyroidism now is very essential to avoid many problems. So, the ministry of health in Egypt added routine estimation of thyroid hormones in the first week of neonatal life with the programs of vaccination for every newborn. The aim of this work was to study the effect of transient neonatal hypothyroidism on the growth of testes during different periods of postnatal testicular development. In this study hypothyroidism was induced in neonates by giving of propylthiouracil [PTU] to the lactating mothers from the day of parturition till weaning [24 days postpartum]. Some mothers were left without treatment and used as control. Thirty male pups were used and divided into two groups [control and experimental] each 15 animals. Their weights were determined at days 15, 25 and 120 then they were sacrificed and testes weights were estimated. One testis was processed for light microscopical study and the other was processed for transmission electron microscopical study. The results revealed that, transient neonatal hypothyroidism induced decrease in neonatal and adult body weights and also decrease in neonatal testis weight. There was very high significant increase in the adult testis weight which was accompanied histologically by apparent increase in Sertoli cells number, Leydig cells and interstitial connective tissue. There were Sertoli cells with immature nuclei in 25 days old animals receiving PTU but not in age-matched control. Sertoli cell tight junction formation was also delayed in treated animals as compared with the control. That mean there were delay of maturation of Sertoli cells with delay of the maturation and proliferation of other testicular components in experimental groups. The results indicate early critical influence of thyroid hormones on the growth and development of testes as reproductive organs

Effect of two injectable contraceptive drugs on the ovary and endometrium of the adult female albino rat: histological and immuno-histochemical study

This study was carried out to determine the histological and immuno-histochemical changes induced in the ovary and endometrium following injection and stoppage of Depot-Provera and Mesigyna, injectable contraceptive drugs. In addition to determine the relation between the proliferative activity of the endometrium and estrogen receptors content of the ovary. Thirty three adult female albino rats were used in this work, which were divided into three groups; the first group [Ia,Ib,Ic] as control. The second group [IIa and IIb] was injected twice with Depot-Provera once/3 weeks then sacrificed after one day and six weeks respectively from the last injection. The third group [IIIa and IIIb], was injected six times with Mesigyna once/week then sacrificed after one day and two weeks respectively from the last injection. The ovaries and uteri of all rats were taken and stained with H and E stain and immuno-histochemical stains. The H and E stained sections of the ovaries in groups IIa and IIIa revealed atresia and degeneration of the growing follicles with few corpora lutea and some cystic dilatations. In group IIb, they still showed some degenerated follicles but in IIIb, some growing follicles and fresh corpora lutea were observed. The endometria of group IIa revealed few, small and quiescent endometrial glands, which were embedded in a highly vascular and edematous stroma.While group IIIa revealed that the endometrial surface was lined partially by pseudostratified epithelial cells. The endometrial glands appeared tubular dilated and embedded in a moderately dense stroma. In group IIb they still showed small and few endometrial glands embedded in a less edematous stroma. However, in group IIIb, the endometrial histology returned to control pattern. The immunohistochemical [SP1] stained sections of the ovaries of group IIa revealed marked decrease of estrogen receptors content, which increased in group IIb, but still less than control level. On contrary, it was apparently increased in group IIIa and then returned to control level in group IIIb. The [Ki-67] stained sections of the endometria of group IIa revealed reduction in the proliferative activity, which still remained lower than control level in group IIb. However, in group IIIa the proliferative activity was increased but returned to the control level in group IIIb. In conclusion, this study clarified that Mesigyna induced less suppressive effects on the ovary and endometrium with an earlier return of their activity than with Depot-Provera. Also, there was an evident direct relationship between the proliferative activity of the endometrium and estrogen receptors content of the ovary