Experimental Study On Effect Of Recombinant Human Growth Hormone Combined With Chemotherapy On Gastric Cancer Implanted In Nude Mice

Objective To invest the effect of different doses of recombinant growth hormone(rhGH) on gastric cancer implanted in nude mice, and its efficacy in combining with chemotherapy (flurouracil, 5-FU).Methods Human gastric cancer MKN-45 model was established in nude mice .The nude mice were divided into six groups.①Control group received daily i.h 0.2 ml and i.c. 0.5 ml sterile saline.②Moderate dose of rhGH group received daily i.h. rhGH 2IU·kg-1.③Low dose of rhGH group received daily i.h. rhGH 0.2 IU·kg-1.④5-FU group received daily i.c.5-FU 25mg·kg-1.⑤Moderate dose of rhGH/5-FU group received daily i.h. rhGH (2IU·kg-1) and i.c.5-FU(25 mg·kg-1).⑥Low dose of rhGH/5-FU group received daily i.h. rhGH(0.2 IU·kg-1) and i.c.5-FU(25mg·kg-1).The results were observed for ten days,including body weight,tumor growth,cell cycle and expression of GHR and IGF-1R.Results After therapy, the body mass of two GH groups was significantly increased compared with control group(P<0.05),the body mass of two rhGH/5-FU groups was significantly increased compared with 5-FU group(P<0.05),but there was no significant difference between GH/5-FU groups and control group(P>0.05). Compared with control group,the average tumor mass and volume were not significantly increased in GH groups(P>0.05),but were obviously reduced in 5-FU group and GH/5-FU groups(P<0.05).There was no significant difference about tumor mass and volume between any GH/5-FU group and 5-FU group(P>0.05).After treatment ,the percentages of S,G0/G1,G2/M phases and proliferation indices(PI)were not significantly changed in GH groups compared with control group(P>0.05),and as well as GH/5-FU groups compared with 5-FU group(P>0.05).The difference caused by GH dose was not significant. Immunohistochemistry was used to detect the expression of IGF-1R and GHR in tumor cells. The results showed no expresion of IGF-1R or GHR, and GH had no effects on it.Conclusion RhGH enhances body mass, but does not stimulate tumor growth, and has no adverse effects on tumor-bearing nude mice. Combined with flurouracil, rhGH does not influence the efficacy of chemotherapy. GH has no significant effects on tumor cell cycle and PI, or the expression of IGF-1R and GHR.