Figure 4. Up-regulation of IGFBP-5 in PDLF. (A) Human PDLF and GF were cultured in DMEM containing 10% FBS until sub-confluent. Total RNA (0.2 µg each) was extracted from cells of passages 4 and 7, and gene-specific primers (1 µM) were used for amplification of IGFBP-5 by RT-PCR. Human β-actin control primers (0.2 µM) were used as internal standard. (B) The cell samples from passage 4 were analyzed by 10% SDS-PAGE with Western blotting and human IGFBP-5 antibody. (C,D) Sections of healthy periodontal tissues from Macaca mulatta monkeys were analyzed by immunohistochemistry as described in MATERIALS & METHODS. Cells immunoreactive for IGFBP-5 are indicated by arrows. Ce, cementum; PDL, periodontal ligament; AvB, alveolar bone; DG, deep gingiva.