Next time your MIL makes a hurtful remark, I would say, "That wasn't very nice." and leave it at that.
Be polite when you see her, give reasonable but not expensive presents and try not to be alone with her for too long.
Don't complain to your husband too much, after all she is his mother, but you could ask him whether making personal remarks is considered all right in his family, as it is considered rude in yours.
Standards differ and we have to find some way of dealing with that. My husband and his family consider personal remarks as quite all right. I found it hard to adjust to.
On the other hand, my mother who had always insisted that making unkind remarks was wrong, started to do so in her latter years. We ignored what we could, but told her quietly that some of her remarks were hurtful. She took no notice, so don't expect your MIL to change.