## 3 Results
### In Vitro Assessment of Probiotic Characteristics of L. plantarum CNTA 628
Total of 4 independent assays with 3 wells per assay was performed. * indicates means that are significantly different (\(p<0.05\)) from the control, data for adhesion of _E. coli_ alone. Figure 6: _Cont._  
Finally, in order to investigate whether _L. plantarum_ would have an impact on intestinal cells, IL-8 was quantified in HT-29 cells. Without LPS stimulation, IL-8 secretion was not affected after _L. plantarum_ exposure (Figure 6F). In a similar manner, in LPS induced- cells, _L. plantarum_ pre-treatment did not induce any changes in IL-8 production compared to the control LPS-stimulated cells (Figure 6F). In summary, _L. plantarum_ significantly increased TNF- \(\alpha\) secretion after exposure to LPS, but it did not show any effect on IL-10, IL-6 or IL-8 production under these conditions. L. plantarum CNTA 628 Lowers Lipid Storage and Reduces Oxidative Stress and Senescence in C. elegans, Contributing to Lifespan Extension  
In this study, it was observed that treatment with different doses of _L. plantarum_ CNTA 628 induced a total lipid reduction effect in _C. elegans_ under normal (NGM media) conditions (Figure 7A), quantified by the Nile red staining method. Moreover, this effect was also achieved when grown under high-glucose (10 mM)-loaded media conditions (Figure 7B). Thus, _L. plantarum_ 628 (\(1.3\times 10^{5}\) CFU/mL) was able to reduce fat accumulation by 18.19% compared to NGM control worms, while it induced a reduction of 7.81% in glucose-loaded media. In both conditions, orlistat (1.5 mg/mL) was used as a positive control, which caused a reduction in the fat percentage of approximately 40%. Interestingly, supplementation with _L. plantarum_ CNTA 628 also resulted in a significant extension in the lifespan of the nematodes (\(p<0.001\)), both in NGM (Figure 7C) and glucose-loaded NGM (MGNg) media (Figure 7D). In fact, the median survival of the nematodes in the group treated with _L. plantarum_ CNTA 628 increased by a day compared to the control NGM group (from 13 days in NGM group to 14 days in probiotic-treated worms). In the case of NGMg media, control worms also exhibited a reduced lifespan, with a median survival of 12 days in comparison to the 13 days of the control NGM group. However, the probiotic supplementation counteracted this lifespan-shortening effect induced by the glucose as the median survival for this group was 15 days (\(p<0.001\)). Figure 6: Cell viability in neutral red assays of RAW 264.7 **(A)** and HT-29 **(B)** after exposure to _L. plantarum_ in untreated (black) or LPS-stimulated (gray) cells. **(C)** Quantification of IL-6 production in RAW 264.7 cells. **(D)** Quantification of TNF\(\alpha\) production in RAW 264.7 cells. **(E)** Quantification of IL-10 production in RAW 264.7 cells. **(F)** Quantification of IL-8 production in HT-29 cells. Results are expressed as mean normalized to negative control \(\pm\) SD. Three independent experiments with three technical replicates each were performed. ANOVA with [PERSON]’s comparisons, \({}^{\star}\)\(p\leq 0.05\), \({}^{\star\star}\)\(p\leq 0.01\), \({}^{\star\star\star}\)\(p\leq 0.001\). To ensure that the reduction in the total accumulated lipids and the extended lifespan effects were not attributed to any potential adverse effects of the probiotic on the worms, we investigated the effect of _L. plantarum_ supplementation on the _C. elegans_ larvae development (Figure S2). This developmental study demonstrated that worms treated with _L. plantarum_ CNTA 628 (at the dose of 3 \(\times\) 10\({}^{5}\) CFU/mL) were able to reproduce normally, with egg-laying and larval development at L1 stages being evident, with no differences in the time of appearance in comparison to the NGM control plates. Hence, we demonstrated how both _L. plantarum_ CNTA 628 can reduce fat accumulation in _C. elegans_ without visibly affecting their development. Thus, we also evidenced that supplementation with _L. plantarum_ CNTA  
Figure 7: _L. plantarum_ enhances health indicators and decreases lipid accumulation in _C. elegans_.