Left Ventricular Myosin Heavy Chains Ratio after Administration of L-Name in Combination with Dexamethasone
الكلمات المفتاحية:
Myosin heavy chains, myosin isozymes, alpha myosin heavy chain, beta myosin heavy chain, Dexamethasone, and L-NAMEالملخص
The main goal of the study is to investigate the effect of Co-administration of Dexamethasone
and NG
-Nitro- L-Arginine Methyl Ester (L-NAME) on the left ventricular myosin heavy chains
(LVMHCs) redistribution and compare it with the cardiac MHCs redistribution caused by LNAME treatment. 44 white adult Swiss mice CD1 (weight range between 18g & 33g, and
their ages range between 8-10 weeks) were used in this study. Animals were distributed
randomly into four groups in a group of eleven as follows: Control group left without
treatment during the whole period of the study, group I were given L-NAME 600mg/L in the
drinking water and injected subcutaneously with dexamethasone phosphate 1mg/kg/day for
22 days, group II were given 600mg/L of L-NAME in the drinking water for 22 days, group III
were injected subcutaneously with dexamethasone phosphate 1mg/kg/day for 22days. Myosin
was extracted by minicing the left ventricular muscle in Laemmli buffer. Cardiac MHCs were
separated with SDS-PAGE procedures. we found that; L-NAME treatment in the group II
shifts α: β ratio towards β LVMHCs compared to control with P values 0.045 . This transition
occurs without significant increase in HW/BW ratio (P values 0.171). Interestingly,
dexamethasone treatment shifts α: β ratio towards β LVMHCs compared to control (P value
0.025) with a significant increase in the HW/BW ratio (P value 0.000). Remarkably, when dexamethasone was injected in combination with L-NAME caused a significant increase in
HW/BW ratio (P value 0.001) without a significant change in alpha or beta LVMHCs
compared to control (P value 0.216). L-NAME treatment changed the LVMHCs from alpha to
beta, and this changing occurs before left ventricular hypertrophy. While dexamethasone
treatment changed the α: β ratio towards β LVMHCs with an increase in the HW/BW ratio.
Finally when dexamethasone administrated in combination with L-NAME reverse the effect
of L-NAME on the LVMHCs with an increase in the HW/BW ratio.
