Hydrolytic enzyme activity in rhesus monkey placenta during early gestational malaria: histochemical studies

Early gestational malaria is found to be more fatal than late gestational infection but the pathophysiology of early gestational placenta, the maternofoetal organ responsible for maintenance of pregnancy, remains unexplored. Present study dealing with hydrolytic enzymes in early gestational placenta of rhesus monkeys during Plasmodium cynomolgi infection was anticipated to provide a better insight into the functional impairment of this organ during early gestational maternal malaria.

Experimental monkeys (Macaca multtta) at 2-2 1/2 months of pregnancy were inoculated with P. cynomolgi bastianelli. After attaining first peak of parasitaemia the animals were anesthetised and placentae were collected for histochemical studies. The snap-frozen, cryostat sections were subjected to histochemical reactions for acid phosphatase and alkaline phosphatase.

The placental syncytiotrophoblast showed a loss in alkaline phosphatase activity, while the trophoblast layers and phagocytic cells of the maternal blood showed increased acid phosphatase activity during early gestational malarial infection. Morphological damage to the placental tissue whenever occurred was associated with altered Alk pase activity.

The altered distribution of Ac pase and Alk pase in malaria infected early gestational placenta has been discussed in the light of placental function. It could be concluded by present studies that these malaria induced changes in hydrolytic enzyme activities in monkey placenta have a direct bearing on functional and morphological integrity of the placental tissue. These changes are apparently responsible for early gestational foetal death and abortions as reported in literature.