## 3 Results
### Analysis of Protein Expression
#### 3.2.2. Cartilage Markers
For the implants inside the joint with or without pre-differentiated MSCs to chondrocytes, we found statistically significant differences (\(p\) = 0.01) and an over-expression of 0.67%\(\uparrow\) for Aggrecan with or without pre-differentiated MSCs. On the other hand, we did not find statistically significant differences for Sox9 (\(p\) = 0.17, over-expression of 0.13%\(\uparrow\)) or COL2A1 (\(p\) = 0.39, over-expression of 0.14%\(\uparrow\)) (see Table 2, Figure 6). Figure 5: Characterization via immunofluorescence of lateral implant after three months. The nuclei of each cell appear in blue (stained with 4′6-diamidino-2-phenylidole (DAPI); magenta markings indicate positivity for different cartilage markers (COL2A1, Aggrecan, and SOX9). \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \begin{tabular}{c} **Months** \\ **(m)** \\ \end{tabular} & **SOX9** & **Mean \%** & \(p\) & \begin{tabular}{c} **Implant** \\ **vs.** \\ **Control** \\ \end{tabular} & **Aggrecan** & **Mean \%** & \(p\) & \
\begin{tabular}{c} **Implant** \\ **vs.** \\ **Control** \\ \end{tabular} & **CO12A1** & **Mean \%** & \(p\) &
\begin{tabular}{c} **Inplant** \\ **vs.** \\ **Control** \\ \end{tabular} \\ \hline \hline \multicolumn{10}{c}{Positive control obtained from healthy joint cartilage} \\ \hline Pre-implant & Control + & 40.1 \(\pm\) 6.2 & N/A & N/A & Control + & 30.7 \(\pm\) 7.6 & N/A & N/A & Control + & 51.6 \(\pm\) 7.7 & N/A & N/A \\ \hline \multicolumn{10}{c}{Lateral implant with pre-differentiated MSCs to chondrocytes (3 months)} \\ \hline \(3\,\mathrm{m}\) & Implant & 69.1 \(\pm\) 8.4 & 0.03 & 0.72\(\uparrow\) & Implant & 62.3 \(\pm\) 5.3 & 0.01 & 1.03\(\uparrow\) & Implant & 39.9 \(\pm\) 11 & 0.15 & 0.23\(\downarrow\) \\ \hline \multicolumn{10}{c}{External joint implant without pre-differentiated MSCs to chondrocytes (6 months)} \\ \hline \(6\,\mathrm{m}\) & Implant & 49.2 \(\pm\) 0.6 & 0.06 & 0.23\(\uparrow\) & Implant & 54.3 \(\pm\) 6.0 & 0.01 & 0.77\(\uparrow\) & Implant & 40 \(\pm\) 5.1 & 0.07 & 0.22\(\downarrow\) \\ \hline \multicolumn{10}{c}{External joint implant with pre-differentiated MSCs to chondrocytes (6 months)} \\ \hline \(6\,\mathrm{m}\) & Implant & 51.6 \(\pm\) 11 & 0.15 & 0.29\(\uparrow\) & Implant & 30.1 \(\pm\) 6.5 & 0.91 & 0.02\(\downarrow\) & Implant & 49.9 \(\pm\) 11 & 0.83 & 0.03\(\downarrow\) \\ \hline \multicolumn{10}{c}{Implant inside joint without pre-differentiated MSCs to chondrocytes (6 months)} \\ \hline \(6\,\mathrm{m}\) & Implant & 45.3 \(\pm\) 4.8 & 0.17 & 0.13\(\uparrow\) & Implant & 51.2 \(\pm\) 7.4 & 0.01 & 0.67\(\uparrow\) & Implant & 58.6 \(\pm\) 14 & 0.39 & 0.14\(\uparrow\) \\ \hline \multicolumn{10}{c}{Implant inside joint with pre-differentiated MSCs to chondrocytes (6 months)} \\ \hline \(6\,\mathrm{m}\) & Implant & 72.1 \(\pm\) 12 & 0.01 & 0.80\(\uparrow\) & Implant & 55.3 \(\pm\) 7.0 & 0.02 & 0.80\(\uparrow\) & Implant & 76.1 \(\pm\) 12 & 0.01 & 0.47\(\uparrow\) \\ \hline \multicolumn{10}{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.} \\ \hline \end{tabular}
\end{table} 
Table 2: Analysis of the expression of markers for cartilage in the implants at three and six months. We used as markers for cartilage: SOX9, Aggrecan, and COL2A1, to compare the expressions of each one of the markers against the positive control (Control +) obtained from healthy cartilage, and based on the results, we determined how many times more or less each marker was expressed concerning the control (Implant vs. Control). After three months, the implant with MSCs pre-differentiated to chondrocytes, SOX9, and Aggrecan behaved similarly to the control, and only COL2A1 was observed to be decreased.