## 3 Results and Discussion
### Genotoxicity and Cytotoxicity Biomarkers
#### 3.2.3 Chromosomal Aberrations as Radioprotection Biomarkers  
The cytogenetic results obtained from the analysis of human lymphocytes exposed to 2 Gy radiation in the presence of varying concentrations of KD and SD are presented in Table 4. After 2 Gy irradiation, the results revealed a decrease in the frequency of dicentric chromosomes (Y\({}_{\rm Dic}\)) with an increase in the concentration of KD and SD. The only concentrations for which the reduction in Y\({}_{\rm Dic}\) (and therefore reduction in damage) was statistically significant (\(p<0.05\)) were KD at medium and high concentrations (400 \(\upmu\)g/mL and 800 \(\upmu\)g/mL) when compared to the control treated with methanol/water at 70:30. In our study, other types of CAs induced by the extracts were found (acentric fragments). The distribution of cells treated and untreated with KD and SD containing a different number of dicentrics is shown in Table 5. After a uniform radiation exposure, the intercellular distribution of dicentrics followed a Poisson distribution in all cases, with or without extracts (U = \(\pm\)1.96). A value of U > 1.96 indicates overdispersion at the 5% level of significance. \begin{table}
\begin{tabular}{l c c c c} \hline
**Conditions** & **MI** & **RMI (\%)** & **PI** & **RPI (\%)** \\ \hline
0 (control) & 0.039 \(\pm\) 0.009 & 100.00 & 1.58 \(\pm\) 0.05 & 100.00 \\
0 + methanol/water 70:30 (control + solvent) & 0.039 \(\pm\) 0.009 & 99.92 & 1.59 \(\pm\) 0.04 & 100.63 \\ \hline KD 50 & 0.041 \(\pm\) 0.009 & 103.47 & 1.57 \(\pm\) 0.05 & 99.37 \\ KD 400 & 0.039 \(\pm\) 0.009 & 98.39 & 1.59 \(\pm\) 0.05 & 100.63 \\ KD 800 & 0.039 \(\pm\) 0.009 & 98.39 & 1.59 \(\pm\) 0.05 & 100.63 \\ \hline SD 50 & 0.041 \(\pm\) 0.009 & 105.00 & 1.57 \(\pm\) 0.05 & 99.37 \\ SD 400 & 0.039 \(\pm\) 0.009 & 98.39 & 1.57 \(\pm\) 0.05 & 99.37 \\ SD 800 & 0.035 \(\pm\) 0.008 * & 88.22 & 1.58 \(\pm\) 0.05 & 100.58 \\ \hline \end{tabular}  
* MI and PI results are expressed as mean \(\pm\) standard errors.
* The difference was statistically significant (\(p<0.05\)).  
\end{table} 
Table 3: Mitotic (MI) and proliferation (PI) indices determined in human peripheral lymphocytes cultured for 72 h in the presence of methanol/water (70:30 \(v\)/\(v\)) solvent and various concentrations of freeze-dried kiwifruit (KD) and strawberry (SD) extracts (50, 400, and 800 \(\upmu\)g/mL). The table also shows each concentration’s relative mitotic index (RMI, %) and relative proliferation index (RPI, %). Several studies have confirmed that the health protective effect associated with kiwifruit is mainly related to their phytochemicals, which may prevent oxidative damage to biological systems by lowering oxidative stress and altering signal transduction pathways involved in cell survival and proliferation [48]. A possible explanation for the irradiation protective effects of antioxidants is a model based on electron spin resonance studies. According to this model, radiation exposure leads to the formation of short-lived radicals like +OH, which are responsible for cell death, as well as long-lived radicals that have the potential to induce mutations and transformations [38]. Our data showed that kiwifruit extracts reduced the chromosomal aberration frequency after irradiation, probably due to its AOP. Regarding biochemicals contributing towards radioprotection, it is known that some phenolics and VC are able to initiate a wide range of physiological responses that reduce severe chromosomal damage [49]. In this sense, VC acted effectively in the sequestration of ROS and, consequently, in the significant reduction in Y\({}_{\text{Dic}}\). This antioxidant property of VC plays a significant role in safeguarding cellular macromolecules, particularly DNA, from oxidative damage [50]. Its protective effect has also been attributed to enhancing other antioxidant compounds' repair and recovery processes [51]. In this sense, the antioxidant and radioprotective properties of AA have been described by [PERSON] et al. [52].