Effects of ethanol on intracorporeal structures of the rat

Alcohol Use Disorders and Their Harmful Effects on the Contractility of Skeletal, Cardiac and Smooth Muscles

Alcohol misuse has deleterious effects on personal health, family, societal units, and global economies. Moreover, alcohol misuse usually leads to several diseases and conditions, including alcoholism, which is a chronic condition and a form of addiction. Alcohol misuse, whether as acute intoxication or alcoholism, adversely affects skeletal, cardiac and/or smooth muscle contraction. Ethanol (ethyl alcohol) is the main effector of alcohol-induced dysregulation of muscle contractility, regardless of alcoholic beverage type or the ethanol metabolite (with acetaldehyde being a notable exception). Ethanol, however, is a simple and "promiscuous" ligand that affects many targets to mediate a single biological effect. In this review, we firstly summarize the processes of excitation-contraction coupling and calcium homeostasis which are critical for the regulation of contractility in all muscle types. Secondly, we present the effects of acute and chronic alcohol exposure on the contractility of skeletal, cardiac, and vascular/ nonvascular smooth muscles. Distinctions are made between in vivo and in vitro experiments, intoxicating vs. sub-intoxicating ethanol levels, and human subjects vs. animal models. The differential effects of alcohol on biological sexes are also examined. Lastly, we show that alcohol-mediated disruption of muscle contractility, involves a wide variety of molecular players, including contractile proteins, their regulatory factors, membrane ion channels and pumps, and several signaling molecules. Clear identification of these molecular players constitutes a first step for a rationale design of pharmacotherapeutics to prevent, ameliorate and/or reverse the negative effects of alcohol on muscle contractility.

Chronic alcoholism associated with diabetes induced apoptosis in the corpus cavernosum of rats

PURPOSE

To evaluate the effects of alcohol exposure and diabetes on apoptotic process in the corpus cavernosum.

METHODS

Forty eight male Wistar rats were divided into four groups: control, diabetic, alcoholic and diabetic-alcoholic. Samples of the corpus cavernosum were prepared to study protein expression of apoptotic genes (Caspases-3 and 9) by immunohistochemistry and Real-Time PCR.

RESULTS

The immunoreactivity of Caspases-3 and -9 was diffuse and higher in the treated groups though there was no significant difference between the experimental groups, only when compared with the control group. An increase was observed in the gene expression of Caspases-9 in the diabetic and ethanol-diabetic groups when compared with control and ethanol groups.

CONCLUSIONS

The association of these factors (ethanol and diabetes) probably can affect the apoptosis mechanism in lesions of the cavernous tissue in the rat penis. Both gene and protein expression of Caspase-9 in diabetic and ethanol-diabetic groups suggest the involvement of the apoptosis cascade from this study model.

Morphological and molecular analysis of apoptosis in the corpus cavernosum of rats submitted to a chronic alcoholism model

Purpose

To evaluate the effect of chronic alcoholism on morphometry and apoptosis mechanism and correlate with miRNA-21 expression in the corpus cavernosum of rats.

Methods

Twenty-four rats were divided into two experimental groups: Control (C) and Alcoholic group (A). After two weeks of an adaptive phase, rats from group A received only ethanol solution (20%) during 7 weeks. The morphometric and caspase-3 immunohistochemistry analysis were performed in the corpus cavernosum. The miRNA-21 expression was analyzed in blood and cavernous tissue.

Results

Chronic ethanol consumption decreased cavernosal smooth muscle area of alcoholic rats. The protein expression of caspase 3 in the corpus cavernosum was higher in A compared to the C group. There was no difference in the expression of miRNA-21 in serum and cavernous tissue between the groups.

Conclusion

Chronic ethanol consumption reduced smooth muscle area and increased caspase 3 in the corpus cavernosum of rats, without altered serum and cavernosal miR-21 gene expression.

Protective effect of apple polyphenols on chronic ethanol exposure-induced neural injury in rats

Apple polyphenols (AP) have attracted much attention due to their various bioactivities. In this study, the protective effect of AP against chronic ethanol exposure-induced neural injury as well as the possible mechanisms were investigated. Body weight, daily average food intake and daily average fluid intake were measured and daily average ethanol consumption was calculated. The influences of AP on motor behavior and memory were detected by locomotor activity test, rotarod test, beam walking test, and Y maze test and novel object recognition test, respectively. The changes of blood ethanol concentration and the oxidative stress were also measured. AP improved chronic ethanol exposure-induced the inhibition of body weight and the decrease of daily average food intake, but did not influence the daily average fluid intake and the daily average ethanol intake, indicating that the improve effect of AP did not result from the decrease of ethanol intake. Motor activity and motor coordination were not influenced after chronic ethanol exposure though the blood ethanol concentration was higher than that in control group. AP improved significantly chronic ethanol-induced the memory impairment and the hippocampal CA1 neurons damage. Further studies found that AP decreased the contents of NO and MDA and increased the levels of T-AOC and GSH in the hippocampus of rats. These results suggest that AP exerts a protective effect against chronic ethanol-induced memory impairment through improving the oxidative stress in the hippocampus.

Adamts1 mediates ethanol-induced alterations in collagen and elastin via a FoxO1-sestrin3-AMPK signaling cascade in myocytes

A variety of stressors including alcohol (EtOH) are known to induce collagen production and fibrotic diseases. Matrix metalloproteinases (MMP) play an important role in regulating fibrosis, but little is known regarding the relationship between EtOH and MMPs. In addition, the signaling cascades involved in this process have not been elucidated. We have identified the MMP Adamts1 as a target of EtOH regulation. To characterize the function of Adamts1, we examined EtOH-induced alterations in collagen I and elastin protein levels in C2C12 myocytes. Incubation of myocytes with 100 mM EtOH decreased elastin and increased collagen content, respectively, and these changes were associated with increased O-GLcNAc modification of Adamts1. Conversely, silencing of Adamts1 by siRNA blocked the adverse effects of EtOH on collagen and elastin levels. Similar results were obtained after treatment with a pharmacological inhibitor of MMP. Changes in collagen were due, at least in part, to a decreased interaction of Adamts1 with its endogenous inhibitor TIMP3. The AMPK inhibitor compound C blocked the EtOH-induced stimulation of collagen and O-GLcNAc Adamts1 protein. Changes in AMPK appear linked to FoxO1, since inhibition of FoxO1 blocked the effects of EtOH on AMPK phosphorylation and O-GLcNAc levels. These FoxO-dependent modifications were associated with an upregulation of the FoxO1 transcription target sestrin 3, as well as increased binding of sestrin 3 with AMPK. Collectively, these data indicate that EtOH regulates the collagen I and elastin content in an Adamts1-dependent manner in myocytes. Furthermore, Adamts1 appears to be controlled by the FoxO1-sestrin 3-AMPK signaling cascade.