Retinoids -Peritoneal exsudate cells
Retinoids are naturally occurring and synthetic analogues of vitamin A and possess antineoplastic activities in vivo together with therapeutic efficacy in a number of dermatologic diseases [6]. Furthermore, they are involved in the maintenance and differentiation of epithelial tissue [5]. In this study the influence of the synthetic retinoid Ro 10-9359 on the peritoneum of NMRI-mice was examined.
For this purpose, groups of seven female mice aged 6-8 weeks were used. The mice were obtained from the Institut ffir Versuchstierkunde Hannover-Linden. Two milligrams Ro 10-9359/kg body weight (b.w.) and 4 mg Ro 10-9359/kg b.w., respectively, were applied orally and daily to each group for 8 days. At the same time PBS without retinoid was instilled into a control group of the same size (sham feeding). The retinoid was suspended in phosphate buffered saline (PBS). Ro 10-9359 was kindly placed at our disposal by the Hoffmann La Roche Co. On the 9th day an i.p. injection was given to some groups. One milliliter thioglycolate broth was injected for the i.p. irritation. Three days later the peritoneal exsudate cells were recovered and referred to as PEC (Thio) [2]. In this way two groups pretreated with 2 mg Ro/kg b.w. and 4 mg Ro/kg b.w. were tested. Two other groups of animals received 2 mg zymosan i.p. (suspended in 1 ml PBS). The cells were recovered 12 h later; they were referred to as PEC (Zy). In all these animals a massage of the abdominal wall lasting 30 s before recovery of cells was performed. In two other experiments the peritoneal cells were determined without any previous i.p. injection. The mice were pretreated for eight days with 2mg Ro/kg b.w. The control animals were subjected to sham feeding. Then the peritoneal cells (PC) were recovered after a 30-s massage or without any previous massage; the cells of the last group were referred to as free peritoneal cells (FPC).
The quantitative recovery of cells from the peritoneal cavity was carried out according to Lemperle [4]. In short, the mice were killed by an overdose of diethyl ether. An incision of skin was made and then 3 ml of washing solution (Hank's balanced salt solution [Serva, Heidelberg, FRG] with 5 IE heparin/ml and 2 ~o FCS)