Establishment of a rat model of transverse tibial bone transfer on the diabetic foot

Zhenxing TU; Bin WANG; Zichen LYU

ABSTRACT

Objective:

To establish a rat model of transverse tibial bone transfer on the diabetic foot.

Methods:

A diabetic model was created by intraperitoneal injection of streptozotocin into 40 SD rats after 5 weeks of high-fat feeding, taking random blood glucose ≥16.7 mmol/L as the criterion for successful modeling. Changes in body weight, food intake, water intake, faecal output and blood glucose were monitored every week after the acclimatization period until random blood glucose ≥16.7 mmol/L was observed for 3 running weeks. After the blood glucose was stabilized, 34 surviving diabetic rats were divided into 2 groups using a random number table. In the experimental group, a transverse transfer outer frame was installed and transverse tibial bone transfer performed after removal of the skin over the dorsal foot; in the control group, a transverse transfer outer frame was installed and the skin over the dorsal foot removed but no transverse tibial bone transfer performed. The wound changes were recorded on the 1, 5, 10, 15 and 20 days after installation of the transverse transfer outer frame. After completion of transverse tibial bone transfer (24 days after modeling of transverse tibial bone transfer), one rat was randomly chosen from each of the 2 groups for angiography while the rest rats were sacrificed for observation of the skin changes on the lower limbs. The densitometric values of CD31 immunohistochemical staining were compared between the 2 groups.

Results:

The random blood glucose increased from (6.89±1.03) mmol/L before modeling to (25.91±6.42) mmol/L at the last test, keeping at ≥16.7 mmol/L for 3 running weeks. The percentages of ulcer healing of the foot dorsal wound in the experimental group on days 5, 10, and 20 were significantly higher than those in the control group ( P<0.05). Gross observation and angiography found more abundant vessels in the lower extremity on the side of transverse transfer in the experimental group. The immunohistochemical staining of the lower limb skin tissue for CD31 found an AOD value of 0.60±0.23 in the experimental group, significantly higher than that in the control group (0.37±0.13) ( t=3.722, P=0.001).

Conclusion:

A rat model of transverse tibial bone transfer has been successfully established through installation of a self-designed transverse transfer outer frame on the basis of a successful rat model of diabetic foot, characterized by improved microcirculation in the lower limbs.