## 3 Results
### Analysis of Protein Expression
#### 3.2.2. Cartilage Markers  
After 3 months, lateral implants were created with pre-differentiated MSCs to chondrocytes; we observed statistically significant differences for the following markers: Sox9 (\(p\) = 0.03), with an over-expression of 0.72%\(\uparrow\), and Aggrecan (\(p\) = 0.01), with an over-expression of 1.03%\(\uparrow\). For the marker COL2A1, we did not find any statistically significant differences (\(p\) = 0.15), and its expression was lower compared to that of the positive control by 0.23%\(\downarrow\) (Figure 5). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \begin{tabular}{c} **Months** \\ **(m)** \\ \end{tabular} & **OPN** & **Mean \%** & \(p\) & \
\begin{tabular}{c} **Implant vs.** \\ **Control** \\ \end{tabular} & **RUNX2** & **Mean \%** & \(p\) &
\begin{tabular}{c} **Implant vs.** \\ **Control** \\ \end{tabular} \\ \hline \multicolumn{8}{c}{External joint implant without pre-differentiated MSCs to osteoblasts (6 months)} \\ \hline
6 m & Implant & 28 \(\pm\) 12 & 0.01 & 0.54\(\downarrow\) & Implant & 25 \(\pm\) 12 & 0.03 & 0.56\(\downarrow\) \\ \hline \multicolumn{8}{c}{External joint implant with pre-differentiated MSCs to osteoblasts (6 months)} \\ \hline
6 m & Implant & 91.4 \(\pm\) 5.7 & 0.01 & 0.50\(\uparrow\) & Implant & 79.8 \(\pm\) 9.5 & 0.01 & 0.42\(\uparrow\) \\ \hline \multicolumn{8}{c}{Implant inside joint, without pre-differentiated MSCs to osteoblasts (6 months)} \\ \hline
6 m & Implant & 37.3 \(\pm\) 17 & 0.73 & 0.39\(\downarrow\) & Implant & 27.1 \(\pm\) 11 & 0.03 & 0.52\(\downarrow\) \\ \hline \multicolumn{8}{c}{Implant inside joint, with pre-differentiated MSCs to osteoblasts (6 months)} \\ \hline
6 m & Implant & 92.4 \(\pm\) 27 & 0.01 & 0.52\(\uparrow\) & Implant & 91.4 \(\pm\) 5.2 & 0.01 & 0.63\(\uparrow\) \\ \hline \multicolumn{8}{c}{\(p\) \(<\) 0.05 are significantly different; N/A: does not apply. The down arrow \(\downarrow\), means an expression lower than that of the positive control and, the arrow up \(\uparrow\), means an expression greater than that of the positive control.} \\ \
\begin{tabular}{c} CTR (positive) \\ \end{tabular} &
\begin{tabular}{c} CTR \\ **(negative)** \\ \end{tabular} & **Lateral implant/c** & **External Implant** & **External Implant** & **Inside Implant** & **Inside Implant** \\ \multicolumn{8}{c}{**joint/nc**} & **joint/nc** & **joint/nc** & **joint/nc** & **joint/c** \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._  
Figure 4: Characterization via immunofluorescence of lateral, external, and internal implants after three and six months. The nuclei of each cell appear in blue stained with DAPI, and green markings indicate positivity for different bone markers that we used (OPN and RUNX2). The positive markers are labeled in green with FITC. c. Implant with pre-differentiated MSCs. nc. Implant without pre-differentiated MSCs. After 6 months, in the external joint implants with or without pre-differentiated MSCs to chondrocytes, we found statistically significant differences only for Aggrecan with or without pre-differentiated MSCs (\(p\) = 0.01), with an over-expression of 0.77%\(\uparrow\). Moreover, we did not find statistically significant differences for Sox9 either with (\(p\) = 0.15, over-expression of 0.29%\(\uparrow\)) or without pre-differentiated MSCs (\(p\) = 0.06, over-expression of 0.23%\(\uparrow\)), Aggrecan in the condition with pre-differentiated MSCs (\(p\) = 0.91, lower expression of 0.02%\(\downarrow\)), or COL2A1 for the two conditions with (\(p\) = 0.83, lower expression of 0.03%\(\downarrow\)) and without pre-differentiated MSCs (\(p\) = 0.07, lower expression of 0.22%\(\downarrow\)). In the implants inside the joint with pre-differentiated MSCs to chondrocytes, we found statistically significant differences between the implants and the positive control for the three markers: Sox9 (\(p\) = 0.01), with an over-expression of 0.80%\(\uparrow\), Aggrecan (\(p\) = 0.02), with an over-expression of 0.80%\(\uparrow\), and COL2A1(\(p\) = 0.01), with an over-expression of 0.47%\(\uparrow\).