Articles

INHIBITION OF THE ACTIVE LYMPH PUMP IN RAT MESENTERIC LYMPHATICS BY HYDROGEN PEROXIDE

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Abstract

The lymphatic system plays an important role in the regulation of fluid and macromolecular exchange. It is a key "safety factor" against the formation of gross edema. Spontaneous contractions in collecting lymphatics of the rat intestine are necessary for the normal transportation of lymph. Hydrogen peroxide is one of the compounds released in inflammation. Therefore, the effects of H₂O₂ on the pumping activity of spontaneously contracting lymphatics were evaluated in the anesthetized rat (n = 16). Diameter oscillations of the mesenteric collecting lymphatics were monitored before and after the application of H₂O₂ (4 and 37 microM). The activity of the lymph pump was evaluated using: contraction frequency (F), stroke volume (SV), ejection fraction (EF), and lymph pump flow (LPF). These parameters were determined from the lymphatic diameter tracings. The following changes in lymphatic activity were seen after a 20 minute exposure to 37 microM H₂O₂: 1) F declined 85%, from 11.6 +/- 1.5 to 1.9 +/- 1.9 cpm. 2) SV fell over 93%. 3) EF decreased 93%, from 0.57 +/- .07 to 0.05 +/- .04. 4) LPF fell dramatically (> 95%) from 41.5 +/- 10.5 to 2.6 +/- 2.5 nl/min. In conclusion, H₂O₂ produced an intense inhibition of the active lymph pump and it is possible that the inhibition of the active pump contributes to the edema which occurs during inflammation.

How to Cite:

Zawieja, D. & Davis, K., (1993) “INHIBITION OF THE ACTIVE LYMPH PUMP IN RAT MESENTERIC LYMPHATICS BY HYDROGEN PEROXIDE”, Lymphology 26(3), 135-142.