Effects of proglumetacin maleate and its major metabolites on allergic air pouch inflammation in rats

The six-day-old rat air pouch model of inflammation: characterization of the inflammatory response to carrageenan

Inflammation was induced in the 6-day-old rat air pouch by injection of carrageenan. The model was characterized in terms of exudate volume, leucocyte influx, cell free protein, prostaglandin E2 levels, and granuloma formation. The time course of all these inflammatory markers, except prostaglandin E2, showed a 3-hr lag followed by a rapid increase to 8 hr. Thereafter, the rate of increase was much slower to 48 hr. Differential cell counts indicated a predominantly polymorphonuclear cell response (75%) during the first 48 hr. Prostaglandin E2 levels increased rapidly after a 3-hr lag, to a maximum of 440 +/- 140 ng/mL at 15 hr and thereafter quickly declined to 140 +/- 60 ng/mL at 21 hr. Prostaglandin E2 levels were the most sensitive inflammatory marker to (S+)-ibuprofen and were reduced dose dependently in the range 0.05 to 1 mg/kg. We have demonstrated the time course for duration of NSAID-induced reduction of prostaglandin E2 levels during inflammation in an individual animal. Rac-ibuprofen (0.1-1 mg/kg) reduced leucocyte influx at 3 and 5 hr, after which drug effects gradually diminished by 24 hr. Rac-ibuprofen at 1 mg/kg significantly reduced the volume of air pouch exudate recovered at 24 hr but had no effect on protein levels.

Increase in ovarian leukotrienes during hormonally induced ovulation in the rat

The ovulatory process was initiated in 25-day-old Wistar rats by injecting human chorionic gonadotropin (hCG; 10 IU sc) 2 days after the animals had been primed with pregnant mares serum gonadotropin (PMSG; 10 IU sc). By 4 h into the ovulatory process, leukotriene (LT) B4 increased 2-fold (P less than 0.001) and LTs C4/D4/E4 increased 1.3-fold (P less than 0.002). By the time of ovulation (10-12 h after the administration of hCG) both eicosanoids declined to their pre-hCG levels. When animals were treated with the cyclooxygenase inhibitor indomethacin at the specific dose of 0.316 mg/rat sc at 1 h before hCG, the ovarian levels of LT B4 and LTs C4/D4/E4 increased to 210% (P less than 0.01) and 113% (P less than 0.05), respectively, above the control levels at 4 h after hCG. Concomitantly, this dosage of indomethacin reduced ovarian prostaglandins (PGs) E and F by 99% (P less than 0.001) and 98% (P less than 0.001), respectively, and it reduced the ovulation rate by 76% (P less than 0.001). Thus it appears this dose of indomethacin blocked the conversion of ovarian arachidonic acid into PGs and shunted this substrate into the lipoxygenase pathways that lead to LT formation. In conclusion, the moderate increase in ovarian LTs is characteristic of inflammatory reactions, and, therefore, these data support the hypothesis that the biochemical events of ovulation resemble an inflammatory process.