P27 | HISTOCHEMICAL APPROACHES FOR EVALUATING THE REPRODUCTIVE HEALTH OF MUSSEL MYTILUS GALLOPROVINCIALIS EXPOSED TO ACUTE THERMAL STRESS

M. Galati, M. A. Oueldi, M. Romeo, T. Cappello, M. Maisan | Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy

The variation of chemical-physical parameters in response to the human impact on natural environments has led to a global increase in temperature (T) that can put at risk the balance of the most exposed ecosystems, like the aquatic-coastal ones¹. Hence, it is needed to find specific biomarkers that can be rapidly used to evaluate the potential cytotoxicological risk of warming on biota. Therefore, to understand the biological responses dependent on climate change in a tissue fundamental to the survival of the species, such as the reproductive system, a thermal priming experiment was performed in which male and female organisms of the edible mussel Mytilus galloprovincialis, previously maintained at 17±1°C, were subjected to 28, 30, or 32°C for 2 h and returned to 17±1°C for 24 h, to then be exposed to a thermal shock at 36°C for 2 h. A negative control group (no T variation) and a positive one (directly exposed to 36 °C without priming) were considered. By histochemical techniques like dPAS/PAS (to highlight glycogen), May Grünwald-Giemsa (to discern haemocyte classes), and Schmorl (to evaluate the innate immune response relative to phenoloxidase), the obtained results validated the reliability of applied methods, confirming how a pre-treatment can influence adaptation to subsequent thermal stress, and how the selected biomarkers are adequate to describe the impact on the reproductive health of an engineer of intertidal hierarchies. Moreover, these data underline the strict interdependence between human actions and the consequences on biodiversity of marine ecosystems, providing new insights on the resistance of biota to this ecological stress factor.

This work was supported by the European Union-Next Generation EU, PNRR MUR-RAISE, CUP B73C24000590006, “TEC-SOS” Project.