there may be no scientific reason, but the image appears as if it comes from scientific investigations.
Everybody in experimental science will tolerate some particles that are not related to the main object of investigation and if you rotate an image, everybody knows that the resulting image will show cut off corners.
Where is the problem?
Do you have a problem with the situation that someone may recognize that you’ve rotated the image? If so, you are to rethink why. It is not a shame to rotate an image and make the rotation recognizable.
Please study the following paper:
Here is a short excerpt:
A perfectly clean background would be unlikely, and probably indicates inappropriate acquisition settings and/or overly zealous image processing (Adler 2005). The presence of some background, rather than calling for artificial elimination, should be considered a reassurance of the authenticity of the data (Nature Editorial 2006).
What could really be criticized is the uneven illumination of your image which appears to be due to suboptimum image acquisition, that should be improved.