## 3 Discussion  
This study confirmed one of our hypotheses that there was a moderate to high correlation in TGF-\(\beta\)1 concentrations between the 3-chamber co-culture and conventional culture device until 96 h. However, the correlation of PDGF-AB concentrations in both devices had moderate to high correlation in the first 24 h, and then it became modestly correlated from 48 to 96 h. Regarding the relationship between platelet concentrations and the released cytokine concentrations, our hypothesis that the concentrations of the cytokine from PRPs at different time points would be correlated with platelet concentrations after production was rejected. A high correlation was only found between platelet and TGF-\(\beta\)1 concentration at 96 h. They were modestly correlated in other time points. Moreover, a negative or modest correlation was found between platelet and PDGF-AB concentration in all time points. PRP was proved to stimulate the proliferation of several cell types in vitro, including osteoblasts [22,23], fibroblasts [24], tenocytes [25], chondrocytes [26], periodontal ligament cells [27], and bone mesenchymal stem cells [28]. It is not only used in the orthopedic field, but it is also commonly used to prevent and treat medication-related osteonecrosis of the jaws [29]. PRP provides a quick, minimally invasive, and relatively low-cost therapeutic strategy to enhance tissue healing because of the increased concentrations of autologous growth factors within [9]. However, there were mixed results in clinical use. For example, \begin{table}
\begin{tabular}{c c c c c c c} \hline  & & **0 h** & **24 h** & **48 h** & **72 h** & **96 h** \\ \hline TGF-\(\beta\)1 & Concentrations & & & & & \\  & 3-chamber & 4250.79 \(\pm\) 1441.14 & 4862.89 \(\pm\) 1641.93 & 4915.04 \(\pm\) 1483.96 & 5324.79 \(\pm\) 1720.3 & 5390.04 \(\pm\) 1371.79 \\  & co-culture & & & & & \\  & 24-well plates & 6052.67 \(\pm\) 1035.28 & 5999.44 \(\pm\) 1040.79 & 6225.11 \(\pm\) 943.76 & 6270.37 \(\pm\) 1371.69 & 6005.04 \(\pm\) 1011.19 \\  & Pearson & & & & & \\  & correlation & & & & & \\  & coefficient & 0.682 & 0.759 & 0.737 & 0.825 & 0.763 \\  & between 2 & & & & & \\  & coefficients & & & & & \\  & 295.78 \(\pm\) 44.53 & 319.74 \(\pm\) 89.34 & 273.81 \(\pm\) 82.14 & 265.16 \(\pm\) 77.69 & 267.85 \(\pm\) 64.32 \\  & 24-well plates & 296.99 \(\pm\) 46.6 & 341.84 \(\pm\) 75 & 308.48 \(\pm\) 45.86 & 334.76 \(\pm\) 41.28 & 350.82 \(\pm\) 47.21 \\  & Pearson & & & & & \\  & correlation & & & & & \\  & coefficient & 0.433 & 0.836 & 0.348 & 0.145 & 0.289 \\  & between 2 & & & & & \\  & devices & & & & & \\  & \(p\)-value & 0.094 & \textless\)0.001 & 0.187 & 0.592 & 0.277 \\ \hline \end{tabular}
\end{table} 
Table 2: The correlation between the concentration of TGF-\(\beta\)1 and PDGF-AB in different time points and culture devices. \begin{table}
\begin{tabular}{c c c c c c c} \hline  & & **0 h** & **24 h** & **48 h** & **72 h** & **96 h** \\ \hline TGF-\(\beta\)1 & Pearson & & & & & \\  & correlation & 0.139 & 0.21 & 0.1 & \(-\)0.14 & 0.95 \\  & coefficient & & & & & \\  & \(p\)-value & 0.537 & 0.347 & 0.657 & 0.952 & 0.673 \\ \hline PDGF-AB & Pearson & & & & & \\  & correlation & \(-\)0.024 & 0.275 & 0.218 & 0.178 & 0.067 \\  & coefficient & & & & & \\  & \(p\)-value & 0.93 & 0.303 & 0.418 & 0.51 & 0.8 [PERSON] and [PERSON] reported favorable outcomes and improved repair integrity when PRP was used in conjunction with rotator cuff repairs [7; 8], while [PERSON] and [PERSON] found no improvement in healing or functional score [30; 31]. [PERSON] et al. reported their results from the augmentation of platelet-rich fibrin matrices in surgically repaired Achilles tendon tears and concluded that PRP might enhance healing and functional recovery [32]. On the other hand, [PERSON] et al., in their Level 2, randomized controlled trial that included 30 patients in whom PRP was applied during Achilles tendon repair, found PRP was not useful for the treatment of Achilles tendon ruptures [33].