European Journal of Pharmacology, 112 (1985) 285-286
285
Flsevier
Rapid communication EFFECTS OF SULPHASALAZINE ON S T R E S S ULCERATION AND M A S T CELL DEGRANULATION IN RAT S T O M A C H (.'LIVE W. OGLE * and CHI H. CHO
Department of Pharmaeologv, Faculty of Medicine, University of Hong Kong, Hong Kong Received 7 May 1985, accepted 7 May 1985
Sulphasalazine has long been used to treat inflammatory bowel disease (Svartz, 1942). However, its effectiveness on other kinds of gastrointestinal lesions remains unexplored. Gastric ulceration due to stress has been shown to depend largely on mast cell degranulation (Cho and Ogle, 1978). A recent report indicates that sulphasalazine can inhibit IgE-mediated mast cell degranulation and histamine release from isolated mast cell preparations (Barrett et al., 1985). Thus, it was considered worthwhile to examine whether sulphasalazine had any effect on gastric ulceration and on mast cell degranulation induced by restraint stress in rats. Female Sprague-dawley rats (175-190 g) were used. They were starved for 48 h but allowed free access to 8% sucrose in 0.2% NaCI w / v which was removed 1 h before restraint (in close-fitting tubular cages of wire mesh) plus cold (4°C) stress for 2 h. Sulphasalazine (Sigma) (63 or 125 mg/kg), or its vehicle (0.1 N NaOH, 5 ml/kg), was injected subcutaneously (s.c.) 30 rain before stress. Nonstressed rats, acting as controls, were left in their starvation cages at room temperature (22 + I°C). All animals were killed by a sharp blow on the head at the end of each 2 h experiment. The stomachs were opened and the severity of ulceration was graded (Cho and Ogle, 1978) by measuring the greatest diameter of the lesions. Five petechiae were regarded as equivalent to a 1 mm ulcer. A piece of glandular mucosa taken along the greater curvature was fixed in 4% lead acetate (E.
Merck) w / v for 2 days and finally processed for mast cell staining by toluidine blue (E. Gurr Ltd.). The details of the method have been described (Cho and Ogle, 1978). The mast cells seen in sections, 7/xm thick, were counted in 42 oil immersion fields which covered an area of 1 mm 2. Restraint stress plus cold for 2 h significantly increased the severity of gastric ulceration and decreased glandular mucosal mast cell numbers (table 1). These effects were inhibited by sulphasalazine pretreatment; statistical significance was reached with the 125 m g / k g dose (P < 0.02).
* To whom all correspondence should be addressed: Department of Pharmacology, Faculty of Medicine, University of Hong Kong, 5 Sassoon Road, Hong Kong.
d p < 0.05, b p < 0.01, " P < 0.001 when compared with corresponding groups in A. d p < 0.02 when compared with its NaOH-injected control in B.
0014-2999/85/$03.30 © 1985 Elsevier Science Publishers B.V.
TABLE 1 Effects of sulphasalazine (given 30 rain beforehand) on stress (restrain plus 4°C for 2 h) ulceration and mast cell counts in the gastric glandular mucosa. Values indicate means_+ S.E.M.; o.i.f. = oil immersion field (1000x). Pretreatment (s.c.)
No. of rats
Mast cell count/ 42 o.i.f.
Ulcer index (mm)
9
71.2_+10.6
0.15 +0,06
10
67.2-+ 3.8
0.27-+0.11
9
68.2-+ 6.1
0.02_+0.02
9
34.4_+ 4.0 ~
6.88+_1.49 ~
10
42.1 + 5.2 "
6.47 -+ 1.95 ~
9
61.9-+ 9.6 d
1.59_+0.46 b.d
(,4) No stress N a O H 0.1 N 5 ml/kg Sulphasalazine 63 m g / k g Sulphasalazine 125 m g / k g
(B) Stress NaOH 0.l N 5 ml/kg Sulphasalazine 63 m g / k g Sulphasalazine 125 m g / k g
286 This is the first report to show that sulphasalazine may have another potential in therapeutics. Since gastric glandular mucosal mast cell degranulation and release of histamine are important in the pathogenesis of stress ulceration (Cho and Ogle, 1978), the antiulcer effect of the drug is likely to be due largely to inhibition of degranulation of these cells (table 1). It has been reported that lipoxygenase activity was strongly inhibited by sulphasalazine (Sircar et al., 1983). Also, the products of lipoxygenase action (i.e. leukotrienes) are more active than histamine in several biological systems (Goldyne, 1984). Therefore, it is concluded that the antiulcer effect of sulphasalazine results from prevention of mast cell degranulation either through a direct action of the drug to stabilise the membranes of these cells, or through inhibition of lipoxygenase activity. In the case of the latter possibility, it is uncertain whether mast cell degranulation is the consequence of direct action by lipoxygenase, or of indirect action by leukotriene, the product of its activity.
Acknowledgement The authors wish to thank Mr. K.M. Li for his skilled technical assistance.
References Barrett, K.E., T.L. Tashof and D.D. Metcalfe, 1985, Inhibition of lgE-mediated mast cell degranulation by sulphasalazine, European J. Pharmacol. 107, 279. Cho, C.H. and C.W. Ogle, 1978, A correlative study of the antiulcer effects of zinc sulphate in stressed rats, European J. Pharmacol. 48, 97. Goldyne, M.E., 1984, Prostaglandins and other eicosanoids, in: Basic Clinical Pharmacology, ed. B.G. Katzung (Lange, Los Altos) p. 217. Sircar, J.C., C.F. Schwender and M.E. Carethers, 1983, Inhibition of soybean lipoxygenase by sulfasalazine and 5-aminosalicylic acid: a possible mode of action in ulcerative colitis, Biochem. Pharmacol. 32, 170. Svartz, N., 1942, Salazopyrin, a new sulfanilamide preparation, Acta Med. Scand. 110, 577.