[Effect of low dose aspirin on osseointegration around titanium implants in osteoporotic rats].

Objective: To investigate the effect of aspirin on osseointegration around titanium implants in ostoeporotic rats and to provide evidence for future researches and clinical application. Methods: A total of 60 female SD rats, aged 3-4 months, were divided into ovariectomy group (Ovx group, n= 48) and sham-ovariectomy group (Sham group, n= 12). The rats in Ovx group received ovariectomy and those in Sham group underwent sham-ovariectomy. Twelve weeks later, six rats in each group were randomly selected to confirm the osteoporosis models. The Ovx group was divided into 4 subgroups with 12 rats in each group, namely the osteoporosis group (OP group), and Aspirin groups (A1, A2, A3 group). Pure screw titanium implants were placed in the right tibia near metaphysis of all rats. Three days after implant surgery, aspirin groups were intragastrically administered aspirin at a dose of 2.06, 4.11, 8.21 mg·kg(-1)·d(-1) (A1, A2, A3), and OP group and Sham group were fed the same amount of normal saline. Four and 12 weeks following implantations surgery, half of the rats in each group were randomly chosen and sacrificed. Implant bone contact rate (IBCR), combined bone lamella width (CBLW) and trabercular width (TW) were observed and calculated using histomorphometric measurement. Results: Four weeks after implantations surgery, the TW and CBLW of rats in A1 group [(39.60±2.77) and (27.56±4.14) μm] and the IBCR, TW and CBLW of rats in A2 group and A3 group [A2: (47.21±4.19)%, (48.74±3.20) and (35.91±3.79) μm; A3: (47.35±6.07)%, (50.27±5.25) and (40.66±2.11) μm] were much higher than those in OP group [(33.89±7.17)%, (32.20±6.10) and (19.77±6.80) μm]( P< 0.05). In term of CBLW, there were no difference between A3 group and Sham group [(46.11±5.87) μm]( P> 0.05). Twelve weeks after implantations surgery, the IBCR and CBLW of rats in A1 group [ (85.86±3.64) %, (53.12±8.68) μm], and the IBCR, TW and CBLW of rats in A2 group and A3 group [A2: (85.64±3.97)%, (69.42±6.78) and (54.19±3.12) μm; A3: (86.22±3.48)%, (75.43±3.50) and (55.79±5.60) μm] were much higher than those in OP group [(77.20±7.14)%, (55.10±2.26) and (41.77±3.13) μm]( P< 0.05). In term of IBCR, there were no difference among A1 group, A2 group, A3 group and Sham group [(90.09±2.21)%]( P> 0.05). Conclusions: The low dose aspirin could promote IBCR, CBLW and TW of osteoporotic rats implants.