Georgia State University ScholarWorks @ Georgia State University Nursing Dissertations (PhD) School of Nursing 12-7-2012 Seizure and Behavioral Phenotyping of the Scn1a Mouse Model of Genetic Epilepsy with Febrile Seizures Plus Ashley W. Helvig Follow this and additional works at: https://scholarworks.edu/nursing_diss Recommended Citation Helvig, Ashley W., "Seizure and Behavioral Phenotyping of the Scn1a Mouse Model of Genetic Epilepsy with Febrile Seizures Plus." Dissertation, Georgia State University, 2012.edu/nursing_diss/32 This Dissertation is brought to you for free and open access by the School of Nursing at ScholarWorks @ Georgia State University. It has been accepted for inclusion in Nursing Dissertations (PhD) by an authorized administrator of ScholarWorks @ Georgia State University. For more information, please contact scholarworks@gsu.
ACCEPTANCE This dissertation, SEIZURE AND BEHAVIORAL PHENOTYPING OF THE SCN1A MOUSE MODEL OF GENETIC EPILEPSY WITH FEBRILE SEIZURES PLUS, by Ashley W. Helvig was prepared under the direction of the candidate’s dissertation committee. It is accepted by the committee members in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Nursing in the Byrdine F. Lewis School of Nursing and Health Professions, Georgia State University.
Decker PhD, RN, RRT, D.ABSM Committee Chairperson ____________________________________ Shih-Yu Lee PhD, RNC Committee Member ____________________________________ Andrew Escayg, PhD Committee Member ____________________________________ Toni Whistler, PhD Committee Member ___________________________________ Date This dissertation meets the format and style requirements established by the Byrdine F. Lewis School of Nursing and Health Professions. It is acceptable for binding, for placement in the University Library and Archives, and for reproduction and distribution to the scholarly and lay community by University Microfilms International. ___________________________________ Joan Cranford, EdD, RN Assistant Dean for Nursing Byrdine F.
Lewis School of Nursing and Health Professions _____________________________________ Margaret C. Wilmoth, PhD, MSS, RN, FAAN Dean and Professor Byrdine F. Lewis School of Nursing & Health Professions AUTHOR’S STATEMENT In presenting this dissertation as a partial fulfillment of the requirements for an advanced degree from Georgia State University, I agree that the Library of the University shall make it available for inspection and circulation in accordance with its regulations governing materials of this type. I agree that permission to quote from, to copy from, or to publish this dissertation may be granted by the author or, in his/her absence, by the professor under whose direction it was written, or in his/her absence, by the Assistant Dean for Nursing, Byrdine F.
Lewis School of Nursing and Health Professions. Such quoting, copying, or publishing must be solely for scholarly purposes and will not involve potential financial gain. It is understood that any copying from or publishing of this dissertation which involves potential financial gain will not be allowed without written permission from the author. Helvig i NOTICE TO BORROWERS All dissertations deposited in the Georgia State University Library must be used in accordance with the stipulations prescribed by the author in the preceding statement.
The author of this dissertation is: Ashley W. Helvig 225 Vinestone Ct. Fayetteville, GA 30215 The director of this dissertation is: Dr. Decker Associate Professor Byrdine F.
Lewis Chair in Nursing Associate Member, Neuroscience Institute Member, Center for Behavioral Neuroscience Byrdine F. Lewis School of Nursing and Health Profession Georgia State University P. Box 3995 Atlanta, GA 30302-4019 Users of this dissertation not regularly enrolled as students at Georgia State University are required to attest acceptance of the preceding stipulations by signing below. Libraries borrowing this dissertation for the use of their patrons are required to see that each user records here the information requested.
NAME OF USER ADDRESS DATE TYPE OF USE (EXAMINATION ONLY OR COPYING) ii VITA Ashley W. Helvig ADDRESS: 225 Vinestone Ct. Fayetteville, GA 30215 EDUCATION: Ph. 2012 Georgia State University Atlanta, Georgia M.
2007 University of West Georgia Carrollton, Georgia B. 1992 Medical College of Georgia Augusta, Georgia PROFESSIONAL EXPERIENCE: 2012- present Assistant Professor, University of West Georgia, Carrollton, GA 2007- 2012 Associate Professor, Gordon College Barnesville, GA 2003- 2009 Staff Nurse, Charge Nurse, Piedmont Fayette Hospital Fayetteville, GA 2003 Clinical Manager, IV Team Staff Builders Home Care, Atlanta, GA 1998-2003 IV Nurse, Visiting Nurse Health System, Atlanta, GA 1995-1998 Case Manager, Central Home Health Care, Newnan, GA 1992-1995 Staff Nurse II, Egleston Children’s Hospital, Atlanta, GA 1994-1995 Home Health Nurse, PRN, Georgia Health Resources, Marietta, GA 1994 Staff Nurse, PRN, Spalding Regional Hospital, Griffin, GA PROFESSIONAL ORGANIZATIONS AND CERTIFICATIONS: 2011-2012 Georgia Association of Nurse Educators 2006-2012 Southern Nursing Research Society 2002-2012 National Certification---Certified Registered Nurse Infusionist 2001-2012 National Infusion Nurses’ Society 1992-2012 Sigma Theta Tau Nursing Honor Society HONORS: 2010 First nursing student member of the Center for Behavioral Neuroscience, Georgia State University 2006 HEART of Fayette recipient, Piedmont Fayette Hospital iii ABSTRACT SEIZURE AND BEHAVIORAL PHENOTYPING OF THE SCN1A MOUSE MODEL OF GENETIC EPILEPSY WITH FEBRILE SEIZURES PLUS by ASHLEY W. HELVIG Genetic epilepsy with febrile seizures plus (GEFS+) is associated with a wide range of neurological dysfunction caused in part by limited function in voltage-gated sodium channels (Escayg & Goldin, 2010; Gambardella & Marini, 2009; Mulley et al. The seizure and behavioral phenotypes, as well as use of non-pharmacologic agents as neuroprotectants in GEFS+, are not well-understood.
An experimental design used an animal model of GEFS+ to 1. explore the effects of stress on seizure phenotype, 2. examine behavioral phenotypes, and 3. study the effects of an omega 3 fatty acid on abnormal behaviors noted in the various paradigms.
This study used C57BL/6J mice with the R1648H missense mutation on the Scn1a gene (engineered in the Escayg lab) (Martin, M. The three specific aims used separate groups of animals for experimentation, and all paradigms were performed under strict laboratory conditions. Data were analyzed using either an independent t-tests, two-way ANOVA or repeated measures two-way ANOVA. Results showed that stress worsens seizure iv phenotype in both the Scn1aR1648H (RH) mutants and wild-type (WT) group with the RH mutants more severely impacted.
In addition, there was clear and consistent evidence for hyperactive locomotor behavior. Lastly, no evidence was found for use of docosahexaenoic acid (DHA, an omega 3 fatty acid) as a neuroprotectant for hyperactivity (DHA was given subcutaneously for two weeks starting at weaning). Outcomes from this study implicate that stress worsens the seizure phenotype in animals with Scn1aR1648H. This study is also the first to report hyperactive locomotor behavior in animals with Scn1aR1648H.
Results from this study may broaden beyond GEFS+ in that we may also be able to apply the findings to other disorders with SCN1A dysfunction. In addition, it may be that genetic variants affecting SCN1A, but not necessarily in epilepsy, may contribute to hyperactivity. This could mean that SCN1A is a candidate gene for hyperactivity. The main goal of nursing care is to reduce and prevent disease morbidity, and knowledge gained from the current study will guide clinical nursing practice, such as targeted behavioral assessment and education, as well as nursing research focusing on children with this genetic disorder.
v TITLE PAGE SEIZURE AND BEHAVIORAL PHENOTYPING OF THE SCN1A MOUSE MODEL OF GENETIC EPILEPSY WITH FEBRILE SEIZURES PLUS by ASHLEY W. HELVIG A DISSERTATION Presented in Partial Fulfillment of Requirements for the Degree of Doctor of Philosophy in Nursing in the Byrdine F. Lewis School of Nursing and Health Professions Georgia State University Atlanta, Georgia 2012 vi COPYRIGHT Copyright by Ashley W. Helvig 2012 vii ACKNOWLEDGMENTS This dissertation would not have been possible without the support, encouragement, and intelligence of a multitude of people.
I would like to first thank Dr. Michael Decker for taking me under his wing and showing me a path that I did not think was possible. You have taught me so much over the past few years and stretched me as a nurse scientist. Thank you so much for your inspiration and keeping me on track.
Your dedication will not be forgotten. I would like to thank my committee members who have helped me so much through this process. Thanks to Dr. Toni Whistler for being so kind and pushing me to do the best job I could do.
Sylvia Lee, I thank for you not only being a wonderful teacher and support in my committee, but for inspiring greatness in research. Andrew Escayg, thank you so much for agreeing to have a nurse in your lab. Your willingness to help me in this process was incredible. A special thank goes to Nikki Sawyer.
Your kindness and encouragement will not be forgotten. You are a wonderful mentor and teacher. To Shelly, Susan and Joy, my Ph. buddies who have helped me survive the past four years, you are very special to me.
Your words of encouragement will always be with me. I am extremely appreciative of the funding support through the Byrdine F. Lewis School of Nursing and Health Professions as well as through the University System of Georgia that have helped to defray costs of my education throughout the past four years. viii To my wonderful family---words cannot express how I feel about you.
Bill, you are an incredible husband. Thank you for the shoulder to cry on, the hugs of encouragement, the multitude of dinners, the midnight road-trips to purchase survival chocolate for me, but most of all your faith in me----your love is overwhelming. To my children, Andrew and Abby---I love you so much. Thank you for the many times you said, “You can do it, mom!” You put up with me not being able to do some things or go places with you, but you never once complained.
You guys are amazing! Thank you to my parents, my sister and the rest of my family for all the prayers and encouragement. I am truly blessed. Most importantly, I would like to thank my Lord and Savior, Jesus Christ, without Whom none of this would be possible. He put all of these people in my life, and for that I am eternally grateful.
ix TABLE OF CONTENTS Section Page List of Tables ……………………………………………………………………………… xiii List of Figures ………………………………. xiv List of Abbreviations …………………………………………………………………. xv Chapter Page I. 1 Significance of the problem………………………………………………….
1 Purpose ………………………………………………………………………9 Significance of the study ……………………………………………………. 11 Theoretical framework ………………………………………………………12 II. 18 Genetics of epilepsy …………………………………………………………18 Animal models of Scn1a …………………………………………………….19 Stress and epilepsy ………………………………………………………….21 Seizure outcomes in response to stress …………………………………….22 Behavioral response to stress in epilepsy …………………….23 Epilepsy and γ-Aminobutyric Acid …………………………………………25 GABA and hyperactivity ……………………………………………………27 x Intervening with omega 3 PUFA’s …………………………………………28 Gaps in our understanding ………………………………………………….40 Description of the genetically engineered mice …………………………….41 Animal setting ………………………………………………………………43 Specific aim I ……………………………………………………………….44 Experimental design ………………………………………………45 Measures ……………………………………………………………46 Sample size and analysis ………………………………………….49 Specific aim II …………………………………………………………….50 Protocol and measures …………………………………………….52 Sample size and analysis ………………………………………….59 Specific aim III ……………………………………………….62 Sample size and analysis ………………………………………….63 Specific aim I ………………………………………………………………63 Specific aim II …………………………………………………………….70 Specific aim III …………………………………………………………….……………………………………………………………93 xi Seizure phenotype in stressed and unstressed RH and WT mice……………94 Behavioral phenotype in RH and WT mice ……………………………….96 Anxiety, depression and social isolation ……………………………98 Conditioned memory ……………………………………………….100 Implications for SCN1A ………………………………………………….101 Neuroprotection using DHA ……………………………………………….101 Implications for nursing practice ……………………………………………102 Strengths and weaknesses of the study …………………………………….105 Recommendations for future research ………………………………………108 Conclusion …………………………………………………………………110 REFERENCES………………………………………………………………………112 APPENDICES ………………………………………………………………………135 xii LIST OF TABLES Table Page Table 1: Groups 1-4 schedule of behavioral paradigms…………………………… 51 Table 2: Latencies and frequencies of seizure activity in RH and WT…………….67 Table 3: Total locomotor activity measures in RH and WT……….72 Table 4: Total exploratory activity measures in RH and WT……………………….75 Table 5: Total locomotor activity measures in RH mutants and WT littermates experiencing the Open Field test during the omega 3 Trial.91 xiii LIST OF FIGURES Figure Page Figure 1. Theory of Stress and Epilepsy (Part A)…………………………………… 15 Figure 2.
Theory of Stress and Epilepsy (Part B)…………………………………. Membrane deformation due to stiff bilayer during protein conformational change………………………………………………………………………………. The location of dysfunction within the sodium channel from the R1648H missense mutation…………………………………………………………………. Photograph of the C57BL/6J mouse…………………………………….
Mouse undergoing Forced Swim Test…………………………………. A photograph of the Social Interaction Paradigm with all 3 mice………. Diagram and measurements of the Social Interaction box………………. Latency to freezing/staring……………………………………………….
Total seizure time………………………………………………………. Total time immobile……………………………………………………. Empty box measures…………………………………………………….