Effects of glutamine on expressions of the myocardial Bcl-2/Bax in rats with sepsis

Objective To investigate the relationship between apoptosis of myocardial cell in the rats with sepsis and the expressions of Bcl-2 and Bax protein,and the protective effect of Glutamine (Gln) on apoptosis of myocardial cell. Method The sepsis models were produced by injecting lipopolysaccharide (LPS) (4 mg/kg) via peritoneal. A total of 72 SD rats were divided into three groups, including the control group, LPS group and LPS + Gln(0.3 g/kg) group. Every group was further divided into four subgroups according to the period from injec-tion to death, 0 h,6 h, 12 h and 24 h (n = 6). Apoptosis of myocardial cells was detected using TUNEL staining, Bcl-2 and Bax protein expressions were measured with immunohistologieal staining and Bcl-2 and Bax mRNA ex-pressions were determined with RT-PCR. Results Apoptosis index of myocardial cells in LPS group was signifi-cantlyhigher than that in the control group (F = 186.786, P < 0.01) at all timepoint. Compared with the control group,the amount of Bax protein in the LPS group was lower at 6 h after administration (F = 9.027, P < 0.01), and higher at 12 h and 24 h after administration; however, the level of Bcl-2 protein expression was significantly lower at all timepoint (F = 301. 142, P < 0.01); and the ratio of Bax/Bcl-2 in the LPS group was obviously higher at all timepoint (F = 527.373, P < 0.01). The expression level of Bax and Bcl-2 mRNA in LPS group gradually elevated and was higher than that in the control group from 6 h (F = 126.157, 80.745, P < 0.01). Compared with the LPS group, at all timepoint, the apoptosis index of apoptotic myocardial cells in the LPS + Gln group was significantly lower (F = 75.187, P < 0.01) ; amount of Bax protein was lower but amout of Bcl-2 pro-tein was higher (F = 20.981, 164.969, P < 0.01) ; the ratio of Bax/Bcl-2 protein expression was lower (F = 141.426, P < 0.01); and the Bax and Bcl-2 mRNA expression levels were lower (F = 103.463,89.373, P < 0.01). Conclusions Bcl-2, anti-apoptosis gene, and Bax, pro-apoptosis gene, play an important role in apopto-sis of myocardial cell in the rats with sepsis. Gin reduces the apoptosis of myocardial cell and improves prognosis of the rat with sepsis via regulation of apoptosi-related gene and protein expressions. Key words: Sepsis; Glutamine; Myocardial cell ; Apoptosis; Bcl-2; Bax; Lipopolysaccharide