Anterior cruciate ligament remnant preservation attenuates apoptosis and enhances the regeneration of hamstring tendon graft

Cheng-Chang Lu; Cheng-Jung Ho; Shu-Jung Chen; Zi-Miao Liu; Paul P-H Chou; Mei-Ling Ho; Yin-Chun Tien

doi:10.1302/2046-3758.121.BJR-2021-0434.R2

Anterior cruciate ligament remnant preservation attenuates apoptosis and enhances the regeneration of hamstring tendon graft

Bone Joint Res. 2023 Jan;12(1):9-21. doi: 10.1302/2046-3758.121.BJR-2021-0434.R2.

Authors

Cheng-Chang Lu^{1

2

3

4

5}, Cheng-Jung Ho^{4

5}, Shu-Jung Chen^{4

5}, Zi-Miao Liu⁴, Paul P-H Chou^{2

4}, Mei-Ling Ho^{3

5

6}, Yin-Chun Tien^{2

4}

Affiliations

¹ Department of Orthopedics, Kaohsiung Municipal Siaogang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
² Department of Orthopedics, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
³ Regenerative Medicine and Cell Therapy Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan.
⁴ Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
⁵ Orthopedic Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan.
⁶ Department of Physiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.

PMID: 36617435
PMCID: PMC9872040
DOI: 10.1302/2046-3758.121.BJR-2021-0434.R2

Abstract

Aims: The effects of remnant preservation on the anterior cruciate ligament (ACL) and its relationship with the tendon graft remain unclear. We hypothesized that the co-culture of remnant cells and bone marrow stromal cells (BMSCs) decreases apoptosis and enhances the activity of the hamstring tendons and tenocytes, thus aiding ACL reconstruction.

Methods: The ACL remnant, bone marrow, and hamstring tendons were surgically harvested from rabbits. The apoptosis rate, cell proliferation, and expression of types I and III collagen, transforming growth factor-β (TGF-β), vascular endothelial growth factor (VEGF), and tenogenic genes (scleraxis (SCX), tenascin C (TNC), and tenomodulin (TNMD)) of the hamstring tendons were compared between the co-culture medium (ACL remnant cells (ACLRCs) and BMSCs co-culture) and control medium (BMSCs-only culture). We also evaluated the apoptosis, cell proliferation, migration, and gene expression of hamstring tenocytes with exposure to co-culture and control media.

Results: Compared to BMSCs-only culture medium, the co-culture medium showed substantially decreased early and late apoptosis rates, attenuation of intrinsic and extrinsic apoptotic pathways, and enhanced proliferation of the hamstring tendons and tenocytes. In addition, the expression of collagen synthesis, TGF-β, VEGF, and tenogenic genes in the hamstring tendons and tenocytes significantly increased in the co-culture medium compared to that in the control medium.

Conclusion: In the presence of ACLRCs and BMSCs, the hamstring tendons and tenocytes significantly attenuated apoptosis and enhanced the expression of collagen synthesis, TGF-β, VEGF, and tenogenic genes. This in vitro study suggests that the ACLRCs mixed with BMSCs could aid regeneration of the hamstring tendon graft during ACL reconstruction.Cite this article: Bone Joint Res 2023;12(1):9-21.

Keywords: Anterior cruciate ligament reconstruction; Apoptosis; Collagen; Hamstring; Hamstring tendon; Ligamentization; Remnant preservation; anterior cruciate ligament (ACL) reconstruction; apoptosis; bone marrow stromal cells; hamstring tendon grafts; hamstring tendons; tendon grafts; transforming growth factor-β; vascular endothelial growth factor.