[Study on in situ expression of type I and III procollagen mRNAs in different parts of keloid and normal skin].

Objective: Based on the histomorphologic differences of three parts of keloid, i.e., invasive, proliferative and senile regions, the study was carried out to explore the differences of expression of type I and type III procollagen mRNAs in the three different parts of keloid and normal skin.

Method: Four samples of keloid from four patients and two samples of normal skin were collected. The expression of pro alpha 1 (I) and pro alpha 1 (III) procollagen mRNAs in keloid and normal skin was investigated by in situ hybridization techniques.

Result: Both type I and III procollagen mRNAs levels increased in keloid, especially type I, resulting in elevated ratios of type I to III procollagen mRNA. In keloid, expressive intention of type I and type III procollagen mRNAs was higher in the papillary layer than in the reticular layer. Also the expressive intention of type I and type III in keloid was higher in invasive and proliferative regions than in the senile region. However, expressive intention of type I and type III procollagen mRNAs in the invasive region of keloid was similar to that in the proliferative region.

Conclusion: The differences of expression of type I and type III procollagen mRNAs in different pathological regions of keloid and normal skin is one cause of forming different pathological regions in keloid.