Effects And Mechanism Of Astragalus Membranaceus On The Apoptosis Of Cord Blood Lymphocytes Of Neonates

Objective To study the effects of Astragalus Menbranaceus(AM) on neonatal lymphocyte apoptosis in cord blood and further to explore the mechanism of the effect.Methods 30 full-term neonates were involved in this study. Cord blood mononuclear cells (CBMC) were in vitro cultured with pure PHA, PHA combined with IL-6 or AM respectively for 48 hours. The apoptosis index of lymphocytes of CBMC after cultivation were determined by AB/EO dying method. The positive expression of CD38 (antigen expressed on mature thymocytes) and CD25(IL-2 receptor) were detected by indirect immu-nofluorescence procedure, the levels of IL-6 in the supernatants of CBMC was detected by ELISA .Results (1)The apoptosis index (AI) of the PHA combined AM group, PHA combined IL-6 group and pure PHA group was (16. 47 + 3. 45)%, (16. 86 4. 03)%, (32. 42 2.82)% respectively. By comparision, the AI of the PHA combined with AM group was lower than that of the pure PHA group (9 = 25. 16,P<0. 001), and the AI of the PHA combined IL-6 group was lower than that of the pure PHA group(9 = 24. 54,P< 0. 001). But there was no difference between the AI of the PHA combined with IL-6 group and that of the PHA combined with AM (q=0. 62,P>0. 05). (2) The positive expression of CD38 of the PHA combined AM group, PHA combined IL-6 group and pure PHA group was (9. 80 1. 79)%, (9. 94 0. 62)% ,and (22.28 + 1.51)% respectively. By comparision, the positive expression of CD38 of the PHA combined with AM was lower than that of the pure PHA group (q=48. 95,P<0. 001), and the positive expression of CD38 of the PHA combined IL-6 group was lower than that of the pure PHA group (q = 48. 42,P< 0. 001). But there was no difference between the positive expression of CD38 of PHA combined with IL-6 group and that of PHA combined with AM (q = 0. 53,P>0. 05). (3)The positive expression of CD25 of the PHA combined AM group, PHA combined IL-6 group and pure PHA group was (83.20 2.44)%, (82.06 3.00)% and (65.78 4.86)% respectively. By comparision, the positive expression of CD25 of the PHA combined with AM was higher than that of the pure PHA group (q=26. 60,P<0. 001), and the positive expression of CD25 of the PHA combined IL-6 group was higher than that of the pure PHAgroup(q=24. 86,P<0. 001). But there was no difference between the positive expression of CD25 of the PHA combined with IL-6 group and that of the PHA combined with AM (q=1. 74,P>0. 05). (4)The level of IL-6 in supernatants of CBMC stimulated with pure PHA and PHA combined with AM was (253. 01+30. 80)pg/ml, (37. 86?2. 15)pg/ml respectively. The IL-6 level of the PHA combined with AM group was significantly higher than that of the pure PHA group (t' = 6. 50,P<0. 001). (5) Cultured for 48 hours, the AI of CBMC had negative correlation with the level of IL-6 of the supernatants (r=- 0. 97, P<0. 001).Conclusions AM can significantly inhibit the apoptosis of CBMC after PHA stimulation in vitro. The possible mechanism may be that AM can increase the cell differentiation from thymocytes to T lymphocytes, Enhance the activation of cord blood lymphocytes and increase the production of IL-6.