Dynamic regulation of apoptotic and antioxidant pathways throughout the reproductive cycle in female blue swimmer crab.

This study investigated the antioxidant and apoptotic systems of blue swimmer crabs at various reproductive stages, providing valuable insights into their potential as biological markers, particularly in the polluted Persian Gulf. Our research along the coasts of Hendijan County, Iran, involved capturing live crabs (167 ± 52.07 g), examining their morphological traits and determining their reproductive stages through dissection and histological analysis. Apoptosis was detected using the TUNEL assay (terminal deoxynucleotidyl transferase dUTP nick end labeling), and enzyme activities including superoxide dismutase, catalase and glutathione peroxidase were measured using colorimetric methods. Variations were observed in the abundance of apoptotic cells within the hepatopancreas across reproductive stages. The second stage exhibited the lowest values and the first stage displayed the highest indicating a potential link between reproductive activity and apoptosis. Furthermore, enzymes representing the antioxidant system demonstrated various activities during ovarian development. Notably, the second ovarian stage demonstrated the highest catalase (5.63 mM <i>per</i> g protein) and malondialdehyde (12.14 mM <i>per</i> g protein) activities indicating an elevated response to oxidative stress. Our findings demonstrated that apoptotic cell numbers were fluctuated throughout the reproductive stages in the crabs, with the highest levels observed during the first stage and the lowest during the second stage. Understanding these fluctuations not only aids in distinguishing between reproductive and non-reproductive phases but also offers valuable insights into the broader physiological changes occurring throughout the cycle.