OBJECTIVETo study the biological effects of the paracrine from ADSC after being stimulated by insulin on vascular endothelial cells.

METHODS(1) ADSC was isolated from human adipose tissue and cultured in vitro. The third generation cells were collected and divided into insulin group (I, cultured with serum-free DMEM containing 1 x 10(-7) mol/L insulin) and control group (C, cultured with serum-free DMEM) according to the random number table, with 6 slots in each group. Three days later, ADSC culture medium (ADSC-CM) was collected for determination of levels of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) by ELISA. (2) Human umbilical vein endothelial cells (HUVEC) were cultured to the third generation, and they were cultured with special nutrient solution and divided into ADSC-CM with insulin stimulation group (AI), ADSC-CM without insulin stimulation group (AC), insulin group (I, with same concentration as above), blank control group (BC) according to the random number table. Three days later, proliferation of HUVEC was determined with MTT method (with expression of absorbance value). Another two samples of HUVEC were respectively divided into 4 groups as above for determination of apoptosis rate with Annexin V/FITC double-staining 12 hours after culture, and HUVEC migration with scratch adhesion test at post scratch hour (PSH) 12, 24, 36, 48. Data were processed with t test.

RESULTS(1) Compared with those in C group [(287 +/- 47), (577 +/- 84) pg/mL, respectively], the secretion levels of VEGF and HGF in I group [(643 +/- 64), (930 +/- 68) pg/mL, respectively] were significantly increased (with t value respectively 18.869, 18.475, P values all below 0.05). (2) The absorbance value of HUVEC in AI and AC groups was 0.847 +/- 0.042, 0.798 +/- 0.022, respectively, which were higher than that in I and BC groups [0.665 +/- 0.028 (with t value respectively 4.579, 3.732), 0.674 +/- 0.031 (with t value respectively 3.761, 4.073), P values all below 0.01], and that in AI group was higher than that in AC group (t = 2.576, P < 0.05). The apoptosis rates of HUVEC in AI and AC groups [(5.8 +/- 1.9)%, (9.0 +/- 2.0)%, respectively] were obviously lower as compared with that in I and BC groups [(30.4 +/- 6.0)% (with t value respectively 12.891, 10.417), (31.4 +/- 7.4)% (with t value respectively 11.474, 9.783), P values all below 0.05 ], and that in AC group was higher than that in AI group (t = 8.548, P < 0.05). The distance of migration of HUVEC in AI and AC groups were greater than that in I and BC groups at PSH 36, 48, and that in AI group was greater as compared with that in AC group (with t value respectively 4.076, 4.573, P values all below 0.05).

CONCLUSIONSParacrine from ADSC after being stimulated by insulin can promote proliferation and migration of HUVEC, and suppress its apoptosis, and it is beneficial for tissue vascularization.