Investigação da ação da melatonina na dinâmica sanguínea de ratas prenhas e na hitigênese do timo e do baço da prole

Abstract

Many factors can interfere in immune system among them we can quote the hormones influence. Between the hormones that provoke alterations in the immune system we can quote melatonin. The interactions between melatonin and immunologic system have been studied a lot, and in practically all the cases, melatonin showed to have immunomodulator effects of immune response. Meantime it is not known the play rolled by this hormone during gestation. Thus this research had as objective analyze the influence of pinealectomy in pregnant rats about the maternal and fetal hemograms, histogenesis and morphometry of thymus and spleen of offspring. It was used 40 rats that were divided in 4 groups: G I – control; G II – sham-pinealectomyzed rats; G III – pinealectomyzed rats treated with placebo; G IV – pinealectomyzed rats treated with melatonin. After the realization of pinealectomy and confirmation of pregnancy, melatonin was administrated in dosage of 0.5mg/Kg in a intraperitoneal way, that was diluted in 0.1 mL of ethanol and 0.3 mL of saline solution. Blood was collected in 7th, 14th and 21th day of pregnancy and the puppies in the 10th day after born, it was collected 500μL. The hematocrit was determinate by the method of microhematocrit, the total count of red blood cells and leukocytes was realized in Neubauer chamber and differential count of leukocytes was carried out through blood smear. The spleen and thymus of offspring was collected in the 1st, 5th and 10th day after born. Theses organs were included in paraffin and the Histological cuts were submitted to histochemistry and morphometry. The results showed that absence of melatonin takes to alterations in the hemogram in the final third of gestation and morphological and morphometrical modifications in thymus and spleen in the 1st and 5th days of life of offspring. It was concluded that maternal melatonin is important to regulation of hemogram in pregnant rats an in the normal development of thymus and spleen of offspring.