Effect of moderate treadmill exercise together with modified hydroxyapatite chitosan composite hydrogel implantation on repair of full-thickness defects of articular cartilage in rats / 中华创伤骨科杂志

ABSTRACT

Objective To investigate the effect of moderate treadmill exercise together with modified hydroxyapatite chitosan composite hydrogel (CS/HA-g-CS) implantation on repair of full-thickness defects of articular cartilage in rats.Methods Full-thickness cartilage defects were drilled in the patellar groove of bilateral femoral condyles in a total of 24 male SD rats before they were randomly assigned into 4 groups.The control group (BC group) was subjected to no exercise or CS/HA-g-CS implantation;the chitosan group (CHI group) to CS/HA-g-CS implantation without exercise;the moderate treadmill exercise group (MIR group) to exercise 4 weeks after modeling without CS/HA-g-CS implantation;the CHI + MIR group to moderate treadmill exercise plus CS/HA-g-CS implantation 4 weeks after modeling.Half of the animals were sacrificed at week 8 and half at week 16 after operation.Femoral condyles were harvested for gross observation and histochemical measurement by O' Driscoll scoring system.mRNA expressions of glycosaminoglycan,collagen type Ⅱ and BMP-2 were detected by RT-PCR.Results Gross observation revealedat 8 weeks after modeling,the CHI + MIR group was significantly better than the other 3 groups,with the BC group in the poorest (P ＜ 0.05);at 16 weeks after modeling,the BC group was significantly poorer than the other 3 groups (P ＜0.05) among which there were no significant differences (P ＞ 0.05).O 'Driscoll scoring revealedat both 8 and 16 weeks after modeling,the CHI + MIR group was significantly better than the other 2 groups and the BC group significantly poorer than the other 3 groups (P ＜ 0.05) but there was no significant difference between the MIR and CHI + MIR groups(P ＞ 0.05).The expressions of collagen type Ⅱ,glycosaminoglycan and BMP-2 were significantly higher in the CHI + MIR group than in the other 3 groups (P ＜ 0.05) and significantly lower in the BC group than in the other 3 groups (P ＜ 0.05).Conclusions Moderate treadmill exercise together with CS/HA-g-CS implantation has significant positive effects on repair of full-thickness defects of articular cartilage in rats than merely moderate treadmill exercise or CS/HA-g-CS implantation alone.The defective cartilage repaired by moderate treadmill exercise together with CS/HA-g-CS implantation contains more collagen type Ⅱ and glycosaminoglycan and shows morphology of nearly normal cartilage.