Background: Cellular senescence may play a role in the development of kidney fibrosis, but its specific association with apoptosis or proliferation have yet to be determined. Objectives: This study aims to determine the effects of unilateral ureteral obstruction (UUO) on proliferation, cellular senescence and apoptosis in kidney fibrosis. Methods: A unilateral ureteral obstruction (UUO) procedure was performed to induce kidney fibrosis in 24 Swiss mice (3 months old, 30 g–40 g). Mice were sacrificed on day 3 (UUO3, n = 6), day 7 (UUO7, n = 6) and day 14 (UUO14, n = 6). Sham operation (SO) procedures were performed on the control group. The expression of Bcl-2, p16 and Bax mRNA was quantified with reverse transcription polymerase chain reaction (RT-PCR). Immunohistochemical (IHC) staining with anti-Bcl-2 and p53 antibodies was used to determine the localisation of proliferation and apoptosis. Data were analysed using one-way ANOVA followed by a post hoc least significant difference (LSD) test (P < 0.05) Results: RT-PCR analysis showed higher mRNA expression of Bcl-2, p16 and Bax in the UUO groups compared with SO group (P < 0.05). Immunostaining showed that Bcl-2 and p53 expression in tubular epithelium in the UUO groups, except Bcl-2 expression was found in interstitial areas of UUO14 group. Conclusion: Senescence in UUO might be associated with epithelial apoptosis and myofibroblast proliferation.

Introduction: Exercise-induced muscle injury stimulates production of proinflammatory cytokines, e.g., TNF-α, resulting in impaired satellite-cell-dependent muscle regeneration. Omega-3 fatty acids emerge to possess anti-inflammatory properties. This study aims to analyze the effect of omega-3 fish oil administration on the levels of TNF-α, MyoD and myogenin expressions of satellite cells after injury. Methods: Twenty-nine adult male Wistar rats were randomized into five groups. Except for control groups, the rats underwent single bout of downhill running exercise and three groups were given low-to-high doses of omega-3 fish oil administration 2 hours after exercise. Blood samples were collected after 24 hours to measure the concentration of TNF-α using ELISA and then the soleus muscles were surgically removed after 72 hours to measure mRNA expressions of MyoD and myogenin using RT-PCR. Results: The results showed lower serum levels of TNF-α (166.83 ± 16.15 vs. 132.83 ± 25.44, 125.00 ± 17.26, 99.66 ± 32.00 pg/mL) and higher expressions of MyoD (0.47 ± 0.19 vs. 0.64 ± 0.20, 1.17 ± 0.16, 1.07 ± 0.14) and myogenin (0.45 ± 0.10 vs. 1.82 ± 0.35, 1.50 ± 0.34, 0.76 ± 0.20) in groups given low-to-high doses of omega-3 fish oil supplementation, respectively, compared to exercise group with no supplement at 72 hours after exercise. Conclusion: Our study suggests that omega-3 fish oil supplementation following muscle injury may accelerate myogenin expression and a low dose of supplementation achieves optimal effect in promoting muscle regeneration. .