الملخص

ABSTRACT The present study aimed to investigate the effects of pyrazinamide drug to induce morphological and histological defects during the embryonic development in some division of central nervous system of Swiss albino mice Mus musculus at the level of light microscope. The pregnant females ingested of pyrazinamide orally as ascending concentrations 1000, 1500, 2000, 2500, 3000mg/kg body weight daily, which started at the 7th day of pregnancy until delivery of neonate. The result revealed at 1000and 1500mg/kg no morphological and histological malformation. At 2000mg/kg no morphological malformations were observed, while histological degeneration and necrosis in the gray matter of spinal cord appears. The ratio of malformes embryos at 2500mg/kg were 22%represented by hypodactylia of left hind limb, swelling trunk, opthalmoptosis, bleeding in head region and some embryos were miniatures. The histological injuries as vaculation of mantle layer in metencephalon, disturbances in size and shape of spinal cord as well as necrosis and vaculation in telencephalon and ventricle diencephalons laterally. At 3000mg/kg of pyrazinamide the malformed embryos. were 33%.The morphological defects were Apex loss of cranium which leads to brain emergence, eye and ear displacement, embryo mongolism, dactylosymphysis, external brain and caudal reduction. Histopthologically many injures appeared as exencephaly, vaculation and necrosis of epindymal and mantle layer of brain are noted. The spinal cord appears for the first time as in fundibular, and lacks the central canal with other malformation, generally sever and wide damages appeared in the CNS in contrast with the control group