Ryanodine receptor 2 contributes to hemorrhagic shock-induced bi-phasic vascular reactivity in rats

Ion Channels Remodeling in the Regulation of Vascular Hyporesponsiveness During Shock

Shock is characterized with vascular hyporesponsiveness to vasoconstrictors, thereby to cause refractory hypotension, insufficient tissue perfusion, and multiple organ dysfunction. The vascular hyporeactivity persisted even though norepinephrine and fluid resuscitation were administrated, it is of critical importance to find new potential target. Ion channels are crucial in the regulation of cell membrane potential and affect vasoconstriction and vasodilation. It has been demonstrated that many types of ion channels including K+ channels, Ca2+ permeable channels, and Na+ channels exist in vascular smooth muscle cells and endothelial cells, contributing to the regulation of vascular homeostasis and vasomotor function. An increasing number of studies suggested that the structural and functional alterations of ion channels located in arteries contribute to vascular hyporesponsiveness during shock, but the underlying mechanisms remained to be fully clarified. Therefore, the expression and functional changes in ion channels in arteries associated with shock are reviewed, to pave the way for further exploring the potential of ion channel-targeted compounds in treating refractory hypotension in shock.

17β-estradiol improves the developmental ability, inhibits reactive oxygen species levels and apoptosis of porcine oocytes by regulating autophagy events

OBJECTIVES

Estrogen plays a critical role in the development and apoptosis of oocytes. Autophagy is an evolutionarily conserved and exquisitely regulated self-eating cellular process with important biological functions including the regulation of reproduction. This study aimed to determine the effect of autophagy regulated by the biologically active form of estrogen (17β-estradiol) in porcine oocyte maturation in vitro.

MATERIALS AND METHODS

We measured the effects of oocyte developmental competencies and autophagic activity in the porcine oocyte regulated by 17β-estradiol using autophagic inhibitor (Autophinib). In addition, we studied the role of autophagy in reactive oxygen species (ROS) levels, mitochondrial distribution, Ca²⁺ production, mitochondrial membrane potential (ΔΨm), and early apoptosis by caspase-3, -8 activity in the mature oocytes.

RESULTS

The results showed that the oocyte meiotic progression and early embryonic development were gradually decreased with Autophinib treatment, which was improved by 17β-estradiol. Immunofluorescence experiments revealed that 17β-estradiol primarily could promote the autophagy in the mature oocytes, and block the reduced-autophagic events by Autophinib. Moreover, 17β-estradiol improved the Autophinib induced high ROS levels, abnormal mitochondrial distribution and low Ca²⁺ production in mature oocytes. Analyses of early apoptosis and ΔΨm showed that autophagy inhibition was accompanied by increased cellular apoptosis, and 17β-estradiol reduced apoptosis rates of mature oocytes. Importantly, autophagy was downregulated by treatment with Autophinib, an activation of caspase-8 and cleaved caspase-3 increased. Those effects were abolished by 17β-estradiol, which could upregulate autophagy.

CONCLUSIONS

Our study have showed important implications that 17β-estradiol could promote efficacy of the development of porcine oocytes, enhance the autophagy, reduce ROS levels and apoptosis activity in vitro maturation.

Estrogen Enhances The Microvascular Reactivity Through Rhoa-Rock Pathway In Female Mice During Hemorrhagic Shock

ABSTRACT

Vascular hypo-reactivity plays a critical role inducing organ injury during hemorrhagic shock. 17β-estradiol (E2) can induce vasodilation to increase blood flow in various vascular beds. This study observed whether E2 can restore vascular hypo-reactivity induced by hemorrhagic shock, and whether E2 effects are associated with RhoA - Rho kinase (ROCK)- myosin light chain kinase phosphatase (MLCP) pathway. The hemorrhagic shock model (40 ± 2 mmHg for 1 h, resuscitation for 4 h) was established in ovary intact sham operation (OVI), ovariectomized (OVX) and OVX plus E2 supplement female mice. Intestinal microvascular loop was used to assess blood flow in vivo, mRNA expression and vascular reactivity in vitro. Hemorrhagic shock significantly reduced norepinephrine microvascular reactivity. Decreased microvascular reactivity was exacerbated by OVX and reversed by E2 supplement. U-46619 (RhoA agonist) increased microvascular reactivity, and C3 transferase (an ADP ribosyl transferase that selectively induces RhoA ribosylation) or Y-27632 (ROCK inhibitor) inhibited sham mice microvascular reactivity. Similarly, U-46619 increased microvascular reactivity in OVI and OVX mice following hemorrhagic shock, which was abolished by Y-27632 or concomitant incubation of okadaic acid (OA) (MLCP inhibitor) and Y-27632. In OVX plus E2 supplement mice with hemorrhagic shock, Y-27632 inhibited microvascular reactivity, which was abolished by concomitant U-46619 application. Lastly, hemorrhagic shock remarkably decreased intestinal loop blood flow, RhoA and ROCK mRNA expressions in vascular tissues in OVX females, but not in OVI females, which were reversed by E2 supplement. These results indicate that estrogen improves microvascular reactivity during hemorrhagic shock, and RhoA-ROCK signaling pathway may mediate E2 effects.

Assessing hemorrhagic shock: Feasibility of using an ultracompact photoacoustic microscope

Hemorrhagic shock, as an important clinical issue, is regarding as a critical disease with a high mortality rate. Unfortunately, existing clinical technologies are inaccessible to assess the hemorrhagic shock via hemodynamics in microcirculation. Here, we propose an ultracompact photoacoustic microscope to assess hemorrhagic shock using a rat model and demonstrate its clinical feasibility by visualizing buccal microcirculation of healthy volunteers. Both functional and morphological features of the microvascular network including concentration of total hemoglobin (C_HbT ), number of blood vessels (VN), small vascular density (SVD) and vascular diameter (VD) were derived to assess the microvascular hemodynamics of different organs. Animal studies show the feasibility of the proposed tool to assess and stage the hemorrhagic shock via microcirculation. in vivo oral imaging of healthy volunteers indicates the translational possibility of this technique for clinical evaluation of hemorrhagic shock.