I am currently doing Western Blots for adipose tissue lysates however I am having a hard time getting even loading especially when probing for loading controls (B-Actin and A-Tubulin). I feel like I've done everything I possibly can to fix this to no avail.

For context, I prepared my lysates using 2% SDS because of the high lipid content and I initially ran Lowry assays to determine the protein concentration. I have been loading 10ug of protein as I do not want to run out of sample since many of my starting samples don't have any tissue left in the tube. I prepare my samples using 4x Laemilli Buffer and my samples to a total volume of 15ul to run on 4-20% precast gels. After issues with some of my samples not showing up I decided to sonicate my lysates and run a Protein A280 assay on the Nanodrop One. Whilst this has improved the quality of some bands I am still having issues with some of my samples not showing up implying that the protein content is too low. I vortex my samples before adding the 4x buffer and I centrifuge after heating my samples prior to loading on the gel.

What else can I possibly do at this point to fix this please?

I have attached examples of my Sonicated lysates probed with B-actin and A-Tubulin. The 6 samples towards the right of both gels ate from the same experimental group