Evaluation of postnatal development of the ovary of albino rat following heroin administration

Twenty four female newly-born albino rats were used for this study. The animals were divided into two groups. The control group contained twelve rats and was injected subcutaneously by distilled water. The treated group contained also twelve rats and was injected subcutaneously by 0.036 mg of pure heroin on the 22 th, 23 th, 24 th days of postnatal life. The ovaries were extracted at 4 and 8 weeks of postnatal life and prepared for light and electron microscopic study. At the 4 th week, ovaries showed different stages of follicular development but most of them were degenerated. The ultrastructure examination revealed that different types of ovarian cells had slight and or severe ultrastructure changes. The slight changes were in the form of small cytoplasmic vacuoles, degeneration of some cytoplasmic organelles, or more heterochromatic nuclei than normal. In other cells the ultrastructure changes were severe in the form of huge cytoplasmic vacuoles, irregular heterochromatic nuclei, or complete loss of the nuclei and cell membranes. At eight weeks treated rats, the light microscopic examination revealed delayed development of the ovaries as evident by complete absence of corpora lutea. Moreover, the ovaries showed more marked degenerative changes in the growing follicles. Also, the ovaries were small in size and showed thick deeply stained germinal epithelium with haemorrhage and congested blood vessels in the hilum and interstitial tissues

Study of subchronic inhalation toxicity of formaldehyde on the ovary of adult female albino rats

In the present work 20 adult female albino rats were used, 6 rats were used as a control and 14 rats were exposed to 6 ppm formaldehyde inhalation for 4 weeks. The exposure was for 6 hours/day, 5 days/week. A special apparatus was used to ensure a uniform dose and to avoid ambient hypoxia. All animals were maintained on balanced diet throughout the experiment. The ovaries were extracted at the end of the experiment for light microscopic examination. Degeneration and fibrosis observed in the present study may affect the fertility of female albino rats but no evidence that formaldehyde was precancerous or carcinogenic to the rat ovary

Effect of hypervitaminosis-A-on the development of the medulla oblongata of the chick embryo

Morphological and histological studied were made on the medulla oblongata of 11 and 15 days chick embryos injected on the 6th and 7th days of incubation with one and two successive doses of vitamin [A] each containing [6000 I.U.], Retardation of growth of the medulla oblongata was indicated by reduction in the size of the medulla, thickening of the ependymal layer and norrowing of the floor of the fourth ventricle, there was thickening in the mantle layer of the middle and caudal levels of the medulla oblongata with poor development of some nuclei. Many neuroblastic cells showed ill- defined cell menbranes and pyknotic nuclei with increased glial tissues and oedema in between. The marginal layer was disrupted, these effects were found to be more marked in chick embryos injected by a second dose of vitamin [A]