[Effect of Shen-Mai injection and aminophylline on diaphragmatic muscle cell apoptosis and related gene expression in rats with chronic hypoxia].

OBJECTIVE

To investigate the effect of Shen-Mai injection (SMI) and aminophylline on diaphragmatic muscle cell apoptosis and the Fas/FasL expression in chronic hypoxic rats.

METHODS

Seventy-five male Wistar rats were randomly divided into three equal groups, control group (A group), SMI group (B group) and aminophylline group (C group). Then each group was further divided into five subgroups of pre-hypoxia, hypoxia 1 w, 2 w, 3 w and 4 w groups (5 rats each). The concentration of oxygen was (10 +/- 3)%, 7 d/w, 8 h/d for all groups, but only B group and C group received SMI (2 ml/d) and aminophylline (10 mg/kg) respectively. Apoptosis and Fas/FasL expression of diaphragmatic muscle cells were examined by the streptavidin biotin-peroxidase complex (SABC) immunohistochemistry techniques and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay, and Dunnett-t test was employed to compare the effects of SMI and aminophylline.

RESULTS

(1) Fas, FasL expression in normal diaphragmatic muscle cells was very low with a positive rate of (2.77 +/- 0.45)% and (2.32 +/- 0.61)%. After hypoxia, the positive rates increased with the time of hypoxia time. SMI showed an inhibition on diaphragmatic muscle cell Fas and FasL expression;after hypoxia 1 w, 2 w, 3 w and 4 w, Fas expression [(6.36 +/- 4.17)%, (9.77 +/- 4.12)%, (18.02 +/- 6.91)% and (21.09 +/- 8.09)%] and FasL expression [(5.32 +/- 6.16)%, (9.58 +/- 3.79)%, (12.01 +/- 8.71)%, (19.43 +/- 10.31)%] in B group were different from those in A group respectively (all P < 0.05). But aminophylline did not show such an effect, the expression of Fas [(10.87 +/- 3.62)%, (24.13 +/- 3.79)%, (35.39 +/- 9.02)%, (39.56 +/- 10.12)%] and FasL [(9.37 +/- 4.07)%, (20.16 +/- 4.88)%, (31.81 +/- 7.07)%, (35.51 +/- 9.13)%] were not significantly different from those in A group respectively (all P > 0.05). (2) Diaphragmatic muscle cell apoptosis was very low in normal rats with a rate of (0.93 +/- 0.29)%, which also increased after hypoxia and the increase was associated with the time of hypoxia. Apoptosis rate was decreased by the administration of SMI, the rates of B group were (5.01 +/- 3.71)%, (9.37 +/- 3.12)%, (14.66 +/- 8.76)%, (18.16 +/- 7.02)%, respectively. Except for the first week, the differences of other weeks were all statistically significant when compared with A groups (all P < 0.05). But the effect of aminophylline was different, as compared to A group, only the apoptosis rate in hypoxia 4 w [(30.92 +/- 11.13)%] of C group being statistically significant different (P < 0.05).

CONCLUSIONS

Fas and FasL participated in diaphragmatic muscle cell apoptosis in rats with chronic hypoxia. SMI showed a definite effect on the Fas and FasL protein expression and decreased diaphragmatic muscle cell apoptosis, which contributed to the therapeutic effect on diaphragmatic fatigue caused by hypoxia.