THE RAT AS AN EXPERIMENTAL MODEL TO STUDY MALFORMATIONS CAUSED BY Mimosa tenuiflora

FIGUEIREDO A.P.M. (1) , BENÍCIO T.M.A. (2), DANTAS  F.P.M. (1), MEDEIROS R.M.T.(3), RIET-CORREA  F. (3)

(1) Under graduate student, Veterinary Medicine, Veterinary Hospital, UFCG, Patos, Paraiba, Brazil. (2) Graduate student, Program in Veterinary Medicine in Small Ruminants, Veterinary Hospital, UFCG, Paraiba, Brazil. (3) Veterinary Hospital, UFCG, Patos, Paraiba, Brazil

Malformations as cleft palate, flexure of fore limbs, microphthalmia and scoliosis caused by the ingestion of Mimosa tenuiflora are common in goats, sheep and cattle in the Brazilian semiarid. The aim of this research was to identify a laboratory animal as an experimental model to study the teratogenic effects of Mimosa tenuiflora. Twenty five pregnant Wistar rats were used. The experimental group had 15 females and received, from the 6o to the 21o day of pregnancy, ration containing 10% of M.tenuiflora seeds. The control group, with 10 females, received the same ration without seeds of M. tenuiflora. There were no significant differences in weight gains, and food and water consumption between treated and control rats. Eighty four malformations were observed in 111 fetuses from the experimental group, and 4 malformations were observed in 58 fetuses from the control group (p<0.05). The more common malformations were cleft palate and scoliosis observed in 33 and 9 treated fetuses, respectively, and in none of the non treated fetuses. Malformations of the cranium were observed in 14 treated fetuses and in none of the non treated fetuses. Other bone malformations were less frequent. The weight and the ossification level of the fetuses of the experimental group were higher than those from the control group (p<0.05). It can be concluded that the seeds of Mimosa tenuiflora are non toxic to the mothers, but contain teratogenic substances for the fetuses, and that the rat can be considered a good experimental model to study the malformations caused by the plant.

KEY-WORDS: rats, malformations, teratogenic plants, Mimosa tenuiflora.

FINANCIAL SUPPORT: Instituto do Milênio, Processo 420012/2005-2, CNPq.

CORRESPONDENCE TO: ROSANE MEDEIROS, Hospital Veterinário, Centro de Saúde e Tecnologia Rural, UFCG, Campus de Patos, Patos, Paraíba, Brasil, Phone: 55+ 83 3423 3409. Fax: 55+ 83- 3421 3231. Email: rmtmed@uol.com.br