Fig. 4.

iMSC-sEVs alleviate senescence of NPCs by upregulating Sirt6 in vitro. a The expression of Sirt6 was assessed by Western blotting. b Densitometric quantification of the relative band intensity in a. n = 3 per group. c Representative micrographs of NPCs stained with SA-β-gal in different treatment groups. SA-β-gal-positive cells are shown in blue. Scale bar, 150 um. d Percentage of SA-β-gal-positive cells. n = 3 per group. e CCK-8 analysis of NPC proliferation in different treatment groups. n = 5 per group. f The expression of P16 was assessed by Western blotting. g Densitometric quantification of the relative band intensity in f. n = 3 per group. h The expressions of collagen II, aggrecan, MMP-3, and ADAMTS-4 were assessed by Western blotting. i Densitometric quantification of the relative band intensity in h. n = 3 per group. *P<0.05, **P< 0.01, ***P< 0.001