Tea polyphenols protect bovine intestinal epithelial cells from the adverse effects of heat-stress in vitro

Heat-stress (HS) leads to impaired gut health, adversely affecting milk production of dairy cows. In the present study, we investigated the protective effects of tea polyphenols (TP) against HS-induced damage in bovine intestinal epithelial cells (BIECs) and explored the underlying mechanisms. Primary BIECs were isolated from bovine duodenum, cultured and treated as follows: (1) control cells incubated in complete medium at 37 °C for 12 h, (2) TP group incubated in medium containing 100 μg/mL TP at 37 °C for 12 h, (3) HS group incubated in medium at 37 °C for 6 h followed by 6 h at 42 °C, and (4) HS + TP group incubated with 100 μg/mL TP for 6 h at 37 °C and 6 h at 42 °C. TP improved cell viability and antioxidant capacity, and decreased apoptosis and LDH activity. TP led to upregulation of Nrf2 and its target antioxidant genes HO-1, NQO1 and SOD1 expression. TP significantly decreased the expression of proinflammatory cytokine genes (NF-κB, IL-6 and TNF-α), and increased expression of the anti-inflammatory cytokine gene, IL-10. The above results suggested that TP protected BIECs from HS-induced adverse effects by alleviating oxidative stress and inflammatory responses, indicating that TP can alleviate HS-induced intestinal damage in dairy cows.

Calcineurin B1 Deficiency Reduces Proliferation, Increases Apoptosis, and Alters Secretion in Enteric Glial Cells of Mouse Small Intestine in Culture

To investigate the roles of calcineurin (CN) in glial cells, we previously generated conditional knockout (CKO) mice lacking CNB1 in glial cells. Because these CKO mice showed dysfunction and inflammation of the small intestine in addition to growth impairment and postweaning death, we have focused on enteric glial cells (EGCs) in the small intestine. In this study, we examined the effects of CNB1 deficiency on the proliferation and survival of EGCs and the expression and secretion of EGC-derived substances in culture to reveal the mechanisms of how CNB1 deficiency leads to dysfunction and inflammation of the small intestine. In primary myenteric cultures of the small intestine, EGCs from the CKO mice showed reduced proliferation and increased apoptosis compared with EGCs from control mice. In purified EGC cultures from the CKO mice, Western blot analysis showed increased expression of S100B, iNOS, GFAP, and GDNF, and increased phosphorylation of NF-κB p65. In the supernatants of purified EGC cultures from the CKO mice, ELISA showed reduced secretion of TGF-β1. In contrast, GDNF secretion was not altered in purified EGC cultures from the CKO mice. Furthermore, treatment with an S100B inhibitor partially rescued the CKO mice from growth impairment and postweaning death in vivo. In conclusion, CNB1 deficiency leads to reduced proliferation and increased apoptosis of EGCs and abnormal expression and secretion of EGC-derived substances, which may contribute to dysfunction and inflammation of the small intestine.