OBJECTIVEThis study investigated the effects of systemic administration of oxytocin (OT) in osteoporotic rats on implant osseointegration.

METHODSTwenty rats were randomly assigned to the control and experimental groups. Initially, the rats underwent bilateral ovariectomy. After 12 weeks, an osteoporosis model was established. Each rat received an implant at the distal and middle femoral metaphysis. Simultaneously, systemic administration was conducted with one group receiving subcutaneous injection of OT (1 mg·kg⁻¹ per day), whereas the other group received placebo injection. After treatment for 4 weeks, another surgery was conducted to remove the thigh bones from the rats containing the implants for an eight-week observation. With the employment of micro-CT, histological observation and push-out test, osseointegration was evaluated. While the rats received thigh-bone removal surgery, another surgery was conducted to remove the tibia metaphysis from the rats of both groups to perform histological observation and micro-CT inspection.

RESULTSThe trabecular bone of tibial samples was intensive and formed woven mesh structure in the experimental group compared with the control group. In the experimental group, the relative bone volume/tissue volume surrounding the implant, the bone contact ratio, and the maximum push-out force of the implant were 0.35%±0.06%, 67.25%±9.06%, and (70.32±10.91) N, respectively, the corresponding values were 0.11%±0.02%, 43.25%±7.01% and (21.65±4.36) N in the control group, and the experimental group increased significantly compared with the control group (P<0.05).

CONCLUSIONSSystemic administration of OT cannot only antagonize the negative effects of osteoporosis but can also promote implant healing and osseointegration of pure titanium implants.