Effect of Splenectomy on gastric carcinogenesis induced by continuous administration of MNNG to rats.

为探讨脾切除对N-甲基-N‘-硝基-N-亚硝基胍(KNNG)诱发大鼠胃癌的影响，将6只Wistar大鼠随机分为3组，每组20只，分别在饮水中加入80、100和120 mg/ml的MNNG，连续44周。为探讨脾功能在胃癌发生中的作用，我们将20只大鼠分为4组，I组，给予MNNG前的假手术，(Sham G)。II组，先切除脾后再注射MNNG(SPX G)。Ⅲ组，给予MNNG(2M SPX G)2个月后行脾切除。(n=5)静脉注射MNNG(4M SPX G)后4个月行脾切除。5只大鼠连续注射MNNG 44周后解剖，观察腺胃肿瘤的数目、大小及组织学变化。胃c-…的发生率MNNG浓度为80µg/ml时，假G2/5(40%)、SPX G2/4(50%)、2M SPX G.3/5(60%)、4M SPX G.3/4(75%)，100µg/mlMNNG浓度分别为2/5、1/5、2/5、3/5,120µg/mlMNNG浓度分别为2/5、1/4、3/5、3/5。4个月后，脾切除组胃癌发生率最高。胃癌的平均大小，假手术组为4.0~2.00 mm，SPX组为11.4~14.4 mm，2M组为5.2~3.7 mm，4HSPX组为4.9~2.4 mm。胃癌侵袭深度：假手术组粘膜下3例，肌层外3例，SPX组2例，Pm外3例，2M SPX G组Sm内5例，Pm外4例，Sm内10例，Pm外1例。提示连续给药4个月后，脾切除对胃癌的发生有一定的促进作用。较少

We examined the effect of splenectomy on the gastric carcinogenesis induced by administration of N-methyl-N'-nitro-N-nitrosoguanidine(KNNG)to rat.Three groups of 20 male Wistar-strain rats, 6 weeds old, received MNNG in the drinking water ad libitum at concentrations of 80, 100 and 120 mug/ml, respectively, for 44 weeks. In order to study the role of splenic function on the gastric carcinogenesis, we classified 20 rats to four groups, I group, sham operation before administration of MNNG, (sham G.) (n=5), II group, splenectomy before administration of MNNG (spx G.) (n=5), III group, splenectomy after 2 months from administration of MNNG (2M spx G.) (n=5) IV group, splenectomy after 4 months from administration of MNNG (4M spx G.) (n=5).The animals were carefully autopsied when after receiving MNNG continuously for 44 weeks.The numbers, sizes and histological study of the tumors in the glandular stomach were examined.In 60 rats, 31 adenocarcinomas were found. The incidences of gastric c … More ancer of each group were as follows, in 80, mug/ml MNNG concentration, sham G. 2/5(40%), spx G. 2/4(50%), 2M spx G. 3/5(60%)and 4M spx G. 3/4(75%) ; in 100, mug/ml MNNG concentration, 2/5, 1/5, 2/5, 3/5 ; in 120mug/ml MNNG concentration, 2/5, 1/4, 3/5, 3/5, respectively. So the incidence of gastric cancer was the highest in the splenectomyed group after 4 months. The mean sizes of the gastric carcinomas were 4.0<plus-minus>2. Omm in the sham G. (6), 11.4<plus-minus>14.4mm in the spx G. (5), 5.2<plus-minus>3.7mm in the 2M spx G. (9)and 4.9<plus-minus>2.4mm in the 4H spx G. (11). The depth of invation of the gastric carcinomas were 3 within submucosal layer(sm)and 3 beyond muscle layer(pm)in the sham G. ; 2 within sm and 3 beyond pm in the spx G., 5 within sm and 4 beyond pm in 2M spx G. and 10 within sm and I beyond pm in 4These results suggested that splenectomy maight have the progressive effect on the gastric carcinogenesis after 4 months in the course of continuous administraion of MNNG. Less