Santos Carla Domingues, Toldo Míriam Paula Alonso, Levy Antonio Marcos Apparecida, Kawasse Laura Midori, Zucoloto Sérgio, do Prado José Clóvis
Laboratório de Parasitologia, Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto FCFRP-USP, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
Acta Trop. 2007 Jun;102(3):143-50. doi: 10.1016/j.actatropica.2007.04.010. Epub 2007 Apr 24.
Dehydroepiandrosterone (DHEA), the predominant steroid hormone produced by adrenal glands has significant effects on the immune system. DHEA enhances immune responses against a wide range of viral, bacterial, and parasitic pathogens. In the present study, we investigated the effects of DHEA treatment during the acute phase of experimental Trypanosoma cruzi infection. Male and female Wistar rats were infected with the Y strain of T. cruzi and treated subcutaneously with 40 mg/kg body weight/day of DHEA. Myocardial parasitism and inflammation were always present in the heart during the acute phase, in male and female infected animals, regardless of DHEA treatment, but the numbers of amastigote nests in cardiomyocytes were significantly lower in DHEA-treated rats. At the end of the acute phase, the nests became rare or virtually absent in all experimental infections. Histological analysis of the adrenal glands showed that treated males displayed an absence of parasites. DHEA treatment also resulted in reduced parasitisim of heart and adrenal glands, as indicated by fewer and smaller amastigote burdens, and less inflammatory infiltrate and tissue disorganization. DHEA treatment also resulted in thymic atrophy as measured both by reduced weight and by a reduction in the number of cultured activated thymocytes. In vitro analysis showed the number of activated macrophages was higher in treated animals. Antibody levels were monitored by complement-mediated lysis. Higher titers were observed in females when compared to males; but DHEA treatment enhanced the percentage of lysis for both sexes. These findings suggest that DHEA can play a role in the control of parasite multiplication.
脱氢表雄酮（DHEA）是肾上腺产生的主要甾体激素，对免疫系统有显著影响。DHEA可增强针对多种病毒、细菌和寄生虫病原体的免疫反应。在本研究中，我们调查了在实验性克氏锥虫感染急性期给予DHEA治疗的效果。将雄性和雌性Wistar大鼠感染克氏锥虫Y株，并皮下注射40mg/kg体重/天的DHEA。在急性期，无论是否接受DHEA治疗，雄性和雌性感染动物的心脏中始终存在心肌寄生虫感染和炎症，但接受DHEA治疗的大鼠心肌细胞中的无鞭毛体巢数量显著减少。在急性期结束时，在所有实验感染中，这些巢变得稀少或几乎不存在。肾上腺的组织学分析表明，接受治疗的雄性动物没有寄生虫。DHEA治疗还导致心脏和肾上腺的寄生虫感染减少，表现为无鞭毛体负担减少且体积变小，炎症浸润和组织紊乱减轻。DHEA治疗还导致胸腺萎缩，这通过体重减轻和培养的活化胸腺细胞数量减少来衡量。体外分析表明，接受治疗的动物中活化巨噬细胞的数量更高。通过补体介导的细胞溶解监测抗体水平。与雄性相比，雌性中观察到更高的滴度；但DHEA治疗提高了两性的细胞溶解百分比。这些发现表明，DHEA可在控制寄生虫增殖中发挥作用。
