OBJECTIVETo investigate the effects of local application of insulin like growth factor-1 (IGF-1) absorbable gelatin sponge complex in implant fossa on osseointegration around implant in osteoporosis rats.

METHODSFemale SD rats, aged 4 months, were randomly individed into ovariectomy group (OVX group) and sham-ovariectomy group (sham-ovx group). The rats in OVX group (n = 15) were ovariectomized, and the rats in Sham-OVX group (n = 10) underwent Sham-ovariectomy. Eight weeks later, 5 rats in each group were randomly selected to confirm the osteoporosis model. The ovariectomized rats were randomly divided into osteoporosis group (OP group) and IGF-1 group after the model was successfully established, 5 rats in each group. Pure titanium implants were implanted in the distal part of right femoral epiphyseal in all groups. Absorbable gelatin sponge particles containing 10 µg IGF-1 were placed in the planting fossa in the IGF-1 group, and absorbable gelatin sponge particles without IGF-1 were used in OP group and sham-OVX group. The rats were sacrificed, and then the distal part of right and left femoral epiphyses were taken out to make undecalcified and decalcified tissue sections respectively after 8 weeks. Combined bone lamella width (CBLW) and implant bone contact rate (IBCR) around implant, trabecular width (TW) and trabecular area percentage (TA) around implant and in the cortical bone of left femoral epiphyses were observed by histomorphometric measurement.

RESULTSThe CBLW, IBCR, TW and TA around implant was (55.43 ± 3.50) µm, (81.79 ± 4.45) %, (57.73 ± 4.29) µm and (62.21 ± 7.42) % respectively in sham-OVX group, (60.22 ± 4.70) µm, (83.67 ± 6.63) %, (48.08 ± 3.63) µm and (58.20 ± 8.93) % respectively in IGF-1 group, and (37.11 ± 2.18) µm, (64.60 ± 5.44) %, (41.19 ± 2.93) µm and (42.21 ± 4.34) % respectively in OP group. The CBLW, IBCR and TW around implant had no differences between IGF-1 and sham-OVX group (P > 0.05), which were significantly higher than those in OP group (P < 0.05). The TW and TA of cortical bone in left distal femoral epiphyses was (60.85 ± 6.64) µm, (61.24 ± 6.98) % respectively in sham-OVX group, (38.68 ± 4.74) µm, (43.89 ± 7.76) % respectively IGF-1 group, (40.46 ± 5.38) µm, (44.63 ± 5.39) % respectively in OP group (P < 0.05). The TW and TA of cortical bone in left distal femoral epiphyses had no differences between IGF-1 group and OP group (P > 0.05), which were all significantly lower than those in sham-OVX group (P < 0.05).

CONCLUSIONSThe local application of IGF-1 gelatin sponge complex can increase bone tissue around implant and improve osseointegration in osteoporosis.