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Background: Follicular cysts contribute significantly to reproductive loss in high-yield dairy cows. This results from the death of follicular granulosa cells (GCs) caused by oxidative stress. Quercetin is known to have significant antioxidant and anti-apoptotic effects. However, the effect of quercetin on follicular cysts has yet been elucidated. Therefore, this study aimed to explore the anti-oxidant and anti-apoptosis effects and potential molecular mechanisms of quercetin in H2O2-induced primary cow GCs and 3-nitropropionic acid (3-NPA)-induced mouse model of oxidative stress and thus treat ovarian cysts in dairy cows. Results: In this study, compared with estrus cows, cows with follicular cysts showed heightened levels of oxidative stress and increased follicular cell apoptosis, while autophagy levels were reduced. A model of oxidative stress was induced in vitro by H2O2 and showed significant increases in apoptosis together with reduced autophagy. These effects were significantly ameliorated by quercetin. Effects similar to those of quercetin were observed after treatment of cells with the reactive oxygen species (ROS) inhibitor N-acetylcysteine (NAC). Further investigations using chloroquine (autophagy inhibitor), rapamycin (autophagy activator), selisistat (SIRT1 inhibitor), and compound C (AMPK inhibitor) showed that chloroquine counteracted the effects of quercetin on oxidative stress-induced apoptosis, while rapamycin had the same effect as quercetin. In addition, the SIRT1/AMPK pathway inhibitors antagonized quercetin-mediated mitigation of the effects of oxidative stress on increased apoptosis and reduced autophagy. Consistent with the results in vitro, in mouse ovarian oxidative stress model induced by 3-NPA, quercetin activated autophagy through the SIRT1/AMPK signaling pathway, while alleviating oxidative stress damage and inhibiting apoptosis in mouse ovaries. Conclusions: These findings indicate that quercetin can inhibit apoptosis in GCs and restore ovarian function by activating autophagy through the SIRT1/ROS/AMPK signaling pathway, suggesting a new direction for the treatment of ovarian follicular cysts in high-yield dairy cows. [ABSTRACT FROM AUTHOR]

Background: The geographic distribution and host-parasite interaction networks of Sarcocystis spp. in small mammals in eastern Asia remain incompletely known. Methods: Experimental infections, morphological and molecular characterizations were used for discrimination of a new Sarcocystis species isolated from colubrid snakes and small mammals collected in Thailand, Borneo and China. Results: We identified a new species, Sarcocystis muricoelognathis sp. nov., that features a relatively wide geographic distribution and infects both commensal and forest-inhabiting intermediate hosts. Sarcocystis sporocysts collected from rat snakes (Coelognathus radiatus, C. flavolineatus) in Thailand induced development of sarcocysts in experimental SD rats showing a type 10a cyst wall ultrastructure that was identical with those found in Rattus norvegicus from China and the forest rat Maxomys whiteheadi in Borneo. Its cystozoites had equal sizes in all intermediate hosts and locations, while sporocysts and cystozoites were distinct from other Sarcocystis species. Partial 28S rRNA sequences of S. muricoelognathis from M. whiteheadi were largely identical to those from R. norvegicus in China but distinct from newly sequenced Sarcocystiszuoi. The phylogeny of the nuclear 18S rRNA gene placed S. muricoelognathis within the so-called S. zuoi complex, including Sarcocystisattenuati, S. kani, S. scandentiborneensis and S. zuoi, while the latter clustered with the new species. However, the phylogeny of the ITS1-region confirmed the distinction between S. muricoelognathis and S. zuoi. Moreover, all three gene trees suggested that an isolate previously addressed as S. zuoi from Thailand (KU341120) is conspecific with S. muricoelognathis. Partial mitochondrial cox1 sequences of S. muricoelognathis were almost identical with those from other members of the group suggesting a shared, recent ancestry. Additionally, we isolated two partial 28S rRNA Sarcocystis sequences from Low's squirrel Sundasciurus lowii that clustered with those of S. scandentiborneensis from treeshews. Conclusions: Our results provide strong evidence of broad geographic distributions of rodent-associated Sarcocystis and host shifts between commensal and forest small mammal species, even if the known host associations remain likely only snapshots of the true associations. [ABSTRACT FROM AUTHOR]