Treatment with Conditioned Medium from Tenocytes Primary Cell Cultures Accelerates Histological and Functional Recovery of Achilles Tendon in Tenotomized Mice

Background.Tendon injuries are responsible for a crescent number of people retirement around the world.Recently, cell-based therapies has been shown to be effective for the treatment of tendon injures.Objective.We aimed to evaluate the effect of local treatment with conditioned medium produced by tenocytes cell cultures on the histological and functional recovery in tenotomized mice.Methods.The tendon cells were cultured for conditioning culture medium that will be used as treatment.The animals were subjected to right Aquilles tenotomy and treated with saline solution (SAL), DMEM (DMEM) and DMEM conditioned in tenocytes cultures (CM) and compared to the control group (CTRL).For histological analysis, tissues were stained with HE.Tendon functionality was measured using the Achilles Functional Index (AFI) and mechanical sensitivity through the paw withdrawal threshold (PWT) using the Von Frey test.Analyzes were performed at 7-, 14-and 21-days post-injury (dpi).Statistics were performed by ANOVA-2 followed by Tukey's post-test, p < 0.01.Results.In the histological analysis, the CM group showed better tissue organization when compared to SAL and DMEM groups.The CM group showed improvement in the PWT at 7° and 14° dpi (2.24 ± 1.15; 2.66 ± 1.06) compared to the DMEM (0.15 ± 0.07; 0 .45± 0.76 p < 0.01) and SAL (0.13 ± 1.15; 0.77 ± 0.95 p < 0.01).The CM group showed functional improvement at 7° and 14° dpi (-40.4 ± 12.6; -36.6 ± 10.4) compared to the DMEM (-76.5 ± 11.7; -71, 6 ± 7.9, p < 0.01) and SAL (-88.8 ± 15; -71.4 ± 12.6 p < 0.01).Conclusions.We conclude that treatment with tenocytes conditioned medium accelerates tendon recovery, promoting improvement in mechanical sensitivity, functionality and tissue organization in the proposed injury model.