In vitro effect of Mirazid on Schistosoma mansoni worms

Measuring Mirazid ability for contracting the worm muscle and its effect on the worm surface ultra-structure can be used to monitor the in vitro effect of any drug. This study aims at investigating the actual effect of Mirazid (a new schistosomicide; purified oleo-resin extract of Myrrh, derived from Commiphora molmol plant) on S. mansoni worms by detecting its in vitro effect. Three groups of white albino mice (5 mice in each group) were infected by 100 cercariae for each mouse. The 3rd group served as a control group. Seven weeks post-infection the mice were sacrificed, perfused and worms were collected. Muscle tension of the worms collected from the first group of mice, was assayed in response to Mirazid in rising concentrations of 100, 200, 300 and 400 nM. The in vitro effect of Mirazid on the muscle tension of single S. mansoni worm was determined using a special device to determine percentage of change in worm length (% shortening). The drug elicited somatic muscle contraction and reached the highest response with 400 nM Mirazid. The maximal increase in the muscle tension (48% shortening) was induced by the highest concentration (400 nM) of the drug. The worms collected from the second group of mice were scanned by electron microscopy. The worms were exposed each to 10 ul of Mirazid in concentration of 10(-6) and collected after 10, 20 and 30 minutes of exposure. Ten minutes exposure caused disruption of the tegument and collapse of tubercles. After 20 minutes, the tegument appeared edematous with more disruption and more shrinkage of tubercles. After 30 minutes, the tegument appeared markedly edematous with extensive disruption of the inter-papillary areas and sensory bulbs. The spines covering the tubercles appeared to be lost.