抄録
This study was aimed at examining the mechanism of anti-inflammatory actions of placenta extract. Placenta extract suppressed carrageenin edema. Carrageenin edema is a model of acute inflammation.
Carrageenin edema is mediated by serotonin, histamine, bradykinin, arachidonic acid prostaglandin E1 and prostglandin E2. We investigated the effect of placenta extract on rat hind paw edema induced by carrageenin edemas chemical mediators.
Placenta extract suppressed serotonin edema and histamine edema. Serotonin and histamine are regarded as allergy inducing factors. Moreover placenta extract had inhibitory effect on prostaglandins. Namely, placenta extract suppressed arachidonic acid-mediated edema and prostaglandin E2-mediated edema.
Arachidonic acid is a precursor of prostaglandin E2.
Arachidonic acid and prostaglandin E2 are regarded as edema enhancing factors. From these results, placenta extract had inhibitory effect on arachidonic acid and prostaglandin E2. Aspirin is a non-steroid anti-inflammtory drug. Non-steroid anti-inflammtory drugs have inhibitory effect of synthetic process from arachidonic acid to prostaglandin E2.
Differently from the mechanism of non-steroid anti-inflammatory drugs, placenta extract might have direct suppressive actions on prostaglandin E2. On the other hand, inflammatory exudates are an important response in inflammation. The post-treatment of placenta extract for 7 days showed anti-exudative actions. This experiment is a model of subacute inflammation. The above results suggested that anti-inflammatory actions of placenta extract are very particular.
