Brener, Z.

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Rev. Inst. Med. trop. São Paulo 6( 4):167-170, julho-ag6sto, 1964 UDC 616.995.122.22-085 CHEMOTHERAPY OF EXPERIMENTAL SCHISTOSOMIASIS V. Studies of some techniques used for the assessment of drug activity Z. BRENER SUMMARY The rapid hepatic shift of Schistosoma mansoni worms which occurs two hours after the administration of active compounds was investigated as a possible screening method in experimentally infected mice. Good results were obtained with soluble antimonial compounds administered by intraperitoneal route but poor results were achieved with drugs given by oral route. A comparative study of the methods of intestinal oogram and distribution of worms was performed on mice treated on the sarne conditions. The mice were examined three days after a 7-day treatment and results seem to prove that both methods have the sarne sensitivity concerning drug activity. INTRODUCTION Many different criteria are being used for the evaluation of drug activity in expe-rimental schistosomiasis and this variety of techniques makes it very difficult to com-pare all the recommended methods. ln this paper an attempt is made to study some new aspects of this important problem, chie-fly the contributions of BuTTLE & K<\-HYYAL 2 and PELLEGRINO et al. 5 , MATERIAL AND METHODS 1 nfection of animals; albino mice, weigh-ing 18-20 g, were infected, through cuta-neous route, with 100 cercariae according to the technique previously described ( BRE-NER 1 ). Drug toxicity; mice weighing 18-20 g were used and the mortality observed for 3 days. The LD50 was determined graphi-cally by the probit method. Distribution of worms: the distribution of worms in the hepatic portal system of trea-ted mice was studied through a perfusion method already described (BRENER 1 ). Comparison between intestinal oogram and distribution of worms: infected mice were treated, from the 50th day of infection, with 7 consecutive doses of different active compounds. Three days after treatment groups of 5 mice were sacrificed and the distribution of worms in the liver, portal vein and mesenteric veins was determined. Frag-ments of the small intestine of the sarne ani-mais were examined microscopically between slide and cover slide. A minimum of 300 viable eggs were counted and classified ac-cording to their evolutive stages. An oogram showing more than 50% of mature eggs was considered as an evidence of drug activity ( PELLEGRINO et al. 5 ), Observation on the rapid shift of the worms to the li ver; the infected animais were treated with a single dose correspond-ing to about 50 per cent of the LD5o and sacrificed after two hours. The distribution of worms was determined through perfusion. Centro de Pesquisas de Belo Horizonte, Instituto Nacional de Endemias Rurais. 167 BRENER, Z. - Chemotherapy of experimental schistosomiasis. V. Studies of some techniques used for the assessment of drug activity. Rev. Inst. Med. trop. Sào Paulo 6:167-170, 1964. Drugs used: sodium antimony llI bis-py-rocatechol-3-5-disulphonate ("Fuadin") ; so-dium antimonyl III gluconate ("Triostib") ; antimony III EDTA; lithium antimony III thiomalate ("Anthiomaline") ; antimony III dimercapto succinate, sodium salt (TWSb) ; potassium antimony III tartrate ( tartar emetic) ; di-hidro-emetine; 1- ( diethylamino ethylamino )-4,6,8-trimethyl-5-azothioxanthone ( "Ciba l 7'581") ; pararosaniline, pamoate salt (TAC); l-methyl-4-diethylamino-ethyla-minothioxanthone ( "Lucanthone ., ) ; 1: 7-bis (p-amino-phenoxy) heptane. RESULTS Table 1 shows the results of distribution of worms in mice treated with a single dose corresponding to about half of the LDso and examined, by perfusion, two hours after drug administration. Tahle 2 shows the re-sults obtained with the intestinal oogram and worm distribution in groups of animais treated with 7 consecutive doses of different drugs and examined three days after drug administration. DISCUSSION Most of the criteria used for the eva-luation of drug activ1ty in experimental schistosomiasis are hased on two important phenomena which follow the administration of active drugs: the shift of the worms to the liver (SCHUBERT 6, STANDEN 7 ) anel the decrease or interruption of egg elimination (KIKUTH & GõNNERT 4, DE CARNIERI 3 ), Changes of the worm distribution occurs after administration of every aclive drug and shows a clear dose-effect relationship. An extremely rapid hepatic shift of worms which takes place about two hours after me-dication was described by BuTTLE & I<A-HYYAL 2 and represents an interesting con-tribution to the dynamics of the migration of S. mansoni worms. The possibility o[ applying this early migration of the para-sites as a screening test was investigated. Very good results are obtained with soluble antimorria! compounds given by intraperi-toneal route but poor results were achieved with insoluble drugs given by oral route and this makes this technique unreliable for screening purposes. According to PELLEGRINO et ai. 5, in his new method of screening drugs, a compound TABLE 1 Perc€ntage of worms in the liver of mice exp,c,rimentally infected with S. mansoni and examined two hours after the administration of a single dose corresponding to about half of the LD,0 of some active compounds. Drugs Sodium antimony bis pyrocatechol 3:5 disulpho-nate ("Fiadin") ........................... s s odium antimonyl III gluconate ( "Triostib") ... odium antimonyl III ethylen diamino tetra-cetate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ithium antimony III thiomalate ("Anthioma-line") ..................................... ntimony III dimercaptosuccinate, sodium salt ("TWSb") ................................. L A p D 1 otassium antimony III tartrate . . . . . . . . . . . . . . . i-hidro-emetine ............................... - ( dietlrylaminoethylamino) 4,6,8-trimethyl-5-azo-thioxanthone-h'ydrochloride ("Ciba 17'581") .. ararosaniline, pamoate salt .................. :7-bis (p-amino-phenoxy) heptane ..... . . . . . . . . p 1 e ontrols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 % worms in the liver NQ of Dosis 1 1 worms (mg/kg) ó 9 Paired (mean) 500 100 100 95 18,0 50 98 100 97 24,6 40 100 100 100 22,5 50 64 87 88 21,2 1000 80 73 34 20,8 25 100 98 94 21,4 10 57 75 10 27,5 580 80 73 36 20,8 800 30 - 5 21,7 400 39 25 36 20,4 - 20 38 3 22,3 BRENER, Z. - Chemotherapy of experimental schistosomiasis. V. Studies of some techniques used for the assessment of drug activity. Rev. Inst. Med. trop. São Pai,Zo 6:167-170, 1964. TABLE 2 Distri.bution of worms in the liver, portal and mesenteric veins and percentage of mature intestinal eggs in mice experimentally infected with S. mansoni, treated during 7 days and examined three days after treatment. Distribution of Percentage of mature intestinal Drugs Dosis paired worms (%) eggs in the 5 mice of each group (mg/kg) 1 1 1 1 1 ---L p M 1 1 2 3 4 5 ~-50 1 100 o o 100 100 100 100 100 1- ( diethylaminoethylamir,o) 25 93 o 7 90 75 100 100 100 4,6,8-trimethyl-5-azothlo-12,5· 84 88 xanthone-hydrochloride 81 o 19 50 87 98 ("Ciba 17'581") 6 12 o 88 36 15 25 31 42 - 6 18 76 32 17 28 30 27 1-methyl-4-diethylaminoethy- 50 80 o 20 100 100 68 65 72 laminothioxanthone-hydro- 25 80 6 14 100 79 27 60 51 chloride ("Lucanthone") - 8 16 76 38 33 24 12 27 1 10 65 30 5 72 75 70 78 72 Di-hydro-emetine 1 5 41 27 30 38 80 79 66 70 - 8 31 60 27 15 30 41 13 0.5 % (diet) 20 8 70 88 96 68 1 85 76 Pararosaniline, pamoate salt 0.25% (diet) 26 21 52 100 69 24 68 74 - 4 20 75 39 28 43 17 21 20 100 o o 100 100 100 100 100 Potassium antimony 10 III 73 10 16 100 100 100 100 100 tartarate 5 50 22 28 100 100 100 100 100 2,5 13 27 60 60 100 21 16 41 - 1 28 71 32 20 10 28 26 100 80 8 12 100 100 100 100 100 Antimony III dimercaptosuc-50 100 63 cinate, sodium salt 54 21 27 25 100 100 ("TWSb") 25 35 21 44 100 31 26 79 45 ·- 8 16 76 38 33 24 12 27 25 73 o Sodium antimonyl III gluco-26 100 100 100 100 100 nate ( "Triostib") 12,5 21 32 47 86 100 100 28 86 - 6 33 60 35 14 25 14 39 L - liver. P - portal vein. M - mesenteric veins. 1s considered active when the intestinal oogram of treated mice shows 50 per cent or more of mature eggs when examined three days after a 7-day treatment. The compa-rative study performed on mice treated on the sarne conditions seems to prove that the method depending on changes of the worm distribution is as sensitive as the oogram method. This experience shows also that there is no need to delay the study of the worm distribution until the 5th or 7th day after drug administration, as commonly clone, because a marked shift is observed as soon as three days after treatment. The choice of the best method would be deter-mined by their practicability in the local conditions of the laboratories engaged on screening prograrns. 169 BRENER, Z. - Chemotherapy of experimental schistosomiasis. V. Studies of some techniques used for the assessment of drug activity. Rev. Inst. Med. trop. São Paulo 6:167-170, 1964. SUMARIO Quimioterapia da esquistossomose experimen-tal; V. Estudo de algumas técnicas usadas para a triagem de drogas. A possibilidade do emprêgo, para a tria-gem de drogas, do fenômeno da migração rápida dos vermes para o fígado, que ocorre cêrca de duas horas após a administração de medicamentos ativos, foi investigada em camundongos experimentalmente inoculados com Schistosoma mansoni. Resultados satis-fatórios, foram obtidos com antimoniais so-lúveis aplicados por via intraperitoneal mas resultados menos evidentes foram obtidos com medicamentos insolúveis administrados por via oral. Estudando, comparativamente, com vanos compostos ativos, os métodos do oograma intestinal e da distribuição de vermes em camundongos experimentalmente inoculados e sacrificados três dias após a administra-ção de 7 doses consecutivas, foi observado que ambos os métodos apresentam sensibili-dade semelhante. REFERENCES 1. BRENER, Z. - Contribuição ao estudo da terapêutica experimental da esquistossomose mansoni. Belo Horizonte, Tese da Fac. Odon-170 2. 3. 4. 5. 6. 7. tologia e Farmácia da Univ. de Minas Ge-rais, 1962. BUTTLE, G. A. H. & KAHYYAL, M. T. -.Rapid hepatic shift of worms in mice infected with Schistosoma mansoni after a single in-jection of tartar emetic. Nature 194:780-781, 1962. CARNERI, I. de - Osservazioni sugli indici dell'azione chemioterapica di sostanze attive su Schistosoma mansoni nel topo. Arch. Ital. Se. Med. Trop. &, Parasito!. 39:400-424, 1958. KIKUTH, W. & GõNNERT, R. - Experi-mental studies on the therapy of Schisto-somiasis. Ann. Top. Med. Parasito!. 42:256-267, 1948, PELLEGRINO, J.; OLIVEIRA, C. A.; FA-RIA, J. & CUNHA, A. S. - New aproach to the screening of drugs in experimental schistosomiasis mansoni in mice. A m. J. Trop. Med. &, Hyg. 11:201-215, 1962. SCHUBERT, M. Conditions for drug testing in experimental schistosomiasis man-soni in mice. Am. J. Trop. Med. & Hyg. 28: 121-136, 1948. STANDEN, O. D. - Experimental schisto-somiasis. III. Chemotherapy and mode of drug action. A nn. Trop. Med. Parasito!. 47: 26-43, 1953. Recebido para publicação em 20 janeiro 1964. 

Chemotherapy of experimental schistosomiasis. V - Studies of some techniques used for the assessment of drug activity

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Chemotherapy of experimental schistosomiasis. V - Studies of some techniques used for the assessment of drug activity

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